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Sample records for alloys by properties

  1. Preparation and properties of biomedical porous titanium alloys by gelcasting.

    Science.gov (United States)

    Yang, Donghua; Shao, Huiping; Guo, Zhimeng; Lin, Tao; Fan, Lianpeng

    2011-08-01

    Porous titanium alloys have been prepared by gelcasting in this study. The elastic solid green body was first polymerized and then vacuum sintered to porous titanium alloys with low contamination by controlling sintering conditions. The microstructure and the total porosity of the vacuum sintered porous Ti-Co and Ti-Mo alloys were analyzed by using scanning electron microscopy and x-ray diffraction. Moreover, compression and bending tests were conducted to investigate their mechanical properties. The results show that open and closed three-dimensional pore morphologies and total porosity ranging from 38.34% to 58.32% can be achieved. In contrast to porous Ti by gelcasting, the compression and bending strengths of porous titanium alloys were significantly increased by adding Mo and Co with Young's modulus ranging between 7-25 GPa, which is close to that of human cortical bone, therefore being suited for potential application in load-bearing implants.

  2. Study on microstructure and properties of Mg-alloy surface alloying layer fabricated by EPC

    Directory of Open Access Journals (Sweden)

    Chen Dongfeng

    2010-02-01

    Full Text Available AZ91D surface alloying was investigated through evaporative pattern casting (EPC technology. Aluminum powder (0.074 to 0.104 mm was used as the alloying element in the experiment. An alloying coating with excellent properties was fabricated, which mainly consisted of adhesive, co-solvent, suspending agent and other ingredients according to desired proportion. Mg-alloy melt was poured under certain temperature and the degree of negative pressure. The microstructure of the surface layer was examined by means of scanning electron microscopy. It has been found that a large volume fraction of network new phases were formed on the Mg-alloy surface, the thickness of the alloying surface layer increased with the alloying coating increasing from 0.3 mm to 0.5 mm, and the microstructure became compact. Energy dispersive X-ray (EDX analysis was used to determine the chemical composition of the new phases. It showed that the new phases mainly consist of β-Mg17Al12, in addition to a small quantity of inter-metallic compounds and oxides. A micro-hardness test and a corrosion experiment to simulate the effect of sea water were performed. The result indicated that the highest micro-hardness of the surface reaches three times that of the matrix. The corrosion rate of alloying samples declines to about a fifth of that of the as-cast AZ91D specimen.

  3. Structural and magnetic properties of nanocrystalline Fe–Co–Si alloy powders produced by mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Shyni, P.C.; Perumal, Alagarsamy, E-mail: perumal@iitg.ernet.in

    2015-11-05

    We report the structural and magnetic properties of nanocrystalline Fe{sub 100−x−y}Co{sub y}Si{sub x} (x = 10, 15, y = 0–20) alloy powders prepared by mechanical alloying process in a planetary ball mill. All the as-milled powders exhibit non-equilibrium α-Fe(Co,Si) solid solution with average crystallite size of 7–11 nm. The lattice constant increases initially up to 10 at.% Co and then decreases with further increase in Co content due to delay in dissolution of Co into Fe lattice by the introduction of more Si. The variations of structural parameters such as average crystallite size, dislocation density and fraction of grain boundary as a function of Co content show good correlations among them. The substitution of Co in Fe{sub 100−x−y}Co{sub y}Si{sub x} alloy powder increases both saturation magnetization and coercivity due to atomic ordering which induce additional magnetic anisotropy. Thermomagnetization studies reveal that Curie temperature (T{sub C}) increases at a rate of 4 K per at.% Co for Co content up to 10 at.% and the rate of increase in T{sub C} reduces to 1.4 K per at.% Co for higher Co addition. The variation of structural and magnetic parameters reveals a strong dependence on the composition of Fe–Co–Si alloy. The observed results show the improvement in soft magnetic properties of nanocrystalline Fe–Co–Si alloy powders by proper substitution of Co and Si for Fe. - Graphical abstract: Structural and magnetic properties of nanocrystalline Fe{sub 100−x−y}Co{sub y}Si{sub x} alloy powders prepared by mechanical alloying process in a planetary ball mill are reported. The non-equilibrium solid solution with nanosized crystallites could be obtained for all the alloy powders. The substitution of Co in Fe{sub 100−x−y}Co{sub y}Si{sub x} alloy powder increases both saturation magnetization and coercivity. The Curie temperature also increases with increasing Co content. The observed results show the improvement in soft magnetic

  4. Structural Analysis and Magnetic Properties of FeCo Alloys Obtained by Mechanical Alloying

    Directory of Open Access Journals (Sweden)

    F. Sánchez-De Jesús

    2016-01-01

    Full Text Available A systematic study on the structural and magnetic properties of Fe100-xCox alloys (10by mechanical alloying is presented. Elemental powders of Fe and Co mixed in an adequate weight ratio were milled at room temperature in a shaker mixer mill using vials and balls of hardened steel as milling media with a ball : powder weight ratio of 12 : 1. The mixtures were milled for 3 h. The results show that, after milling, for almost all the composition (up to x=60, solid solutions based on bcc structures were obtained. For Co-rich alloys (x≥70, different phases were found, revealing the formation of a metastable intermetallic phase (FeCo, wairauite together with fcc-Co and hcp-Co phases. The specific saturation magnetization increases by increasing Co content, reaching a maximum value of 225 emu/g for hcp-Fe70Co30, and then it shows a diminution up to 154 emu/g for bcc-Fe30Co70. All studied alloys (Fe100-xCox present low coercivity, in the range from 0 to 65 Oe, which is lower than reported. The coercivity increases with the increment in Co, reaching a maximum of 64.1 Oe for Fe40Co60. After that, the coercivity falls up to 24.5 Oe for Co-rich alloys, which make them a very low coercive material.

  5. Fatigue properties of an 1421 aluminum alloy processed by ECAE

    Science.gov (United States)

    Mogucheva, A.; Kaibyshev, R.

    2010-07-01

    Fatigue properties and fatigue crack growth rate were examined in an Al-Mg-Li-Sc-Zr allow subjected to equal channel angular extrusion (ECAE) with rectangular shape of channels up to a total strain of ~4 at a temperature of 325°C followed by solution treatment with subsequent oil quenching with aging. After this processing the fraction recrystallized was ~80pct; the deformed microstructure remains essentially unchanged under solution treatment due to high density of Al3Sc coherent dispersoids playing a role of effective pinning agents. It was shown that the fatigue limit of this material attained a value of ~185 MPa. Thermomechanical processing provided a decrease in fatigue crack propagation growth rate and an increase in the stress intensity factor, K1c, in comparison with extruded bar. However, characteristics of crack propagation resistance did not attain values suitable for application of this alloy for critical aircraft components.

  6. Fatigue properties of an 1421 aluminum alloy processed by ECAE

    Energy Technology Data Exchange (ETDEWEB)

    Mogucheva, A; Kaibyshev, R, E-mail: mogucheva@bsu.edu.r [Belgorod State University, Pobeda 85, Belgorod, 308015 (Russian Federation)

    2010-07-01

    Fatigue properties and fatigue crack growth rate were examined in an Al-Mg-Li-Sc-Zr allow subjected to equal channel angular extrusion (ECAE) with rectangular shape of channels up to a total strain of {approx}4 at a temperature of 325{sup 0}C followed by solution treatment with subsequent oil quenching with aging. After this processing the fraction recrystallized was {approx}80pct; the deformed microstructure remains essentially unchanged under solution treatment due to high density of Al{sub 3}Sc coherent dispersoids playing a role of effective pinning agents. It was shown that the fatigue limit of this material attained a value of {approx}185 MPa. Thermomechanical processing provided a decrease in fatigue crack propagation growth rate and an increase in the stress intensity factor, K{sub 1c}, in comparison with extruded bar. However, characteristics of crack propagation resistance did not attain values suitable for application of this alloy for critical aircraft components.

  7. RESEARCH OF INFLUENCE OF ALLOYING BY BORON ON PROPERTIES THE IRON-CARBON ALLOYS

    Directory of Open Access Journals (Sweden)

    K. V. Kobyakov

    2014-01-01

    Full Text Available It is shown that for improvement of physical-mechanical properties of the cast products which have hard usage, the boron carbide, which can be used at carrying out process of thermo-chemical treatment of cast products of iron-carbon alloy, is of great interest.

  8. Study on improved tribological properties by alloying copper to CP-Ti and Ti–6Al–4V alloy

    International Nuclear Information System (INIS)

    Copper alloying to titanium and its alloys is believed to show an antibacterial performance. However, the tribological properties of Cu alloyed titanium alloys were seldom studied. Ti–5Cu and Ti–6Al–4V–5Cu alloys were fabricated in the present study in order to further study the friction and wear properties of titanium alloys with Cu additive. The microstructure, composition and hardness were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM) and hardness tester. The tribological behaviors were tested with ZrO2 counterface in 25% bovine serum using a ball-on-disc tribo-tester. The results revealed that precipitations of Ti2Cu intermetallic compounds appeared in both Ti–5Cu and Ti–6Al–4V–5Cu alloys. The tribological results showed an improvement in friction and wear resistance for both Ti–5Cu and Ti–6Al–4V–5Cu alloys due to the precipitation of Ti2Cu. The results also indicated that both CP-Ti and Ti–5Cu behaved better wear resistance than Ti–6Al–4V and Ti–6Al–4V–5Cu due to different wear mechanisms when articulated with hard zirconia. Both CP-Ti and Ti–5Cu revealed dominant adhesive wear with secondary abrasive wear mechanism while both Ti–6Al–4V and Ti–6Al–4V–5Cu showed severe abrasive wear and cracks with secondary adhesive wear mechanism due to different surface hardness integrated by their microstructures and material types. - Highlights: • Ti–5Cu and Ti–6Al–4V–5Cu alloys were fabricated with Cu additive. • Precipitations of Ti2Cu intermetallic compounds appeared after alloying Cu. • The precipitation of Ti2Cu improved both friction and wear resistance. • Plowing was the dominant material removal force with severe plowing phenomenon. • Different dominant and secondary wear mechanisms appeared with different hardness

  9. Microstructure and Properties of W-15Cu Alloys Prepared by Mechanical Alloying and Spark Plasma Sintering Process

    Institute of Scientific and Technical Information of China (English)

    ZHANG Qiaoxin; SHI Xiaoliang; YANG Hua; DUAN Xinglong

    2008-01-01

    W-15Cu composite powders prepared by mechanical alloying (MA) of raw powders were consolidated by spark plasma sintering (SPS) process at temperature ranged 1230-1300℃ for 10min and under a pressure of 30MPa. By using high energy milling, particles containing very fine tungsten grains embedded in copper, called composite particles, could be produced. The W grains were homogeneously dispersed in copper phase, which was very important to obtain W-Cu alloy with high mechanical properties, fine and homogeneous microstructure. The microstructure and properties of W-15Cu alloys prepared by SPS processes at different temperature were researched. The results show that W-15Cu alloys consolidated by SPS can reach 99.6% relative density, and transverse rupture strength (TRS) is 1400.9MPa, Rockwell C hardness (HRC) is 45.2, the thermal conductivity is 196W/m·K at room temperature, the average grain size is less than 2μm, and W-15Cu alloy with excellent properties, homogeneous and fine microstructure is obtained.

  10. Bulk amorphous metallic alloys: Synthesis by fluxing techniques and properties

    Energy Technology Data Exchange (ETDEWEB)

    He, Yi; Shen, Tongde; Schwarz, R.B.

    1997-05-01

    Bulk amorphous alloys having dimensions of at least 1 cm diameter have been prepared in the Pd-Ni-P, Pd-Cu-P, Pd-Cu-Ni-P, and Pd-Ni-Fe-P systems using a fluxing and water quenching technique. The compositions for bulk glass formation have been determined in these systems. For these bulk metallic glasses, the difference between the crystallization temperature T{sub x}, and the glass transition temperature T{sub g}, {Delta}T = T{sub x} - T{sub g}, ranges from 60 to 1 10 K. These large values of {Delta}T open the possibility for the fabrication of amorphous near net-shape components using techniques such as injection molding. The thermal, elastic, and magnetic properties of these alloys have been studied, and we have found that bulk amorphous Pd{sub 40}Ni{sub 22.5}Fe{sub 17.5}P{sub 20} has spin glass behavior for temperatures below 30 K. 65 refs., 14 figs., 3 tabs.

  11. Microstructure and Thermomechanical Properties of Shape Memory Alloys TI50-NI50 Elaborated by Arc Melting and by Powder Metallurgy

    OpenAIRE

    Olier, P.; Brachet, J.; Guenin, G.

    1995-01-01

    This study was focussed on the elaboration and transformation of Ti50Ni50 shape memory alloys in relation to structural and thermomechanical properties. An original method for producing TiNi alloys by powder metallurgy (PM), through combustion synthesis, was developed. After hot extrusion, intermetallic rods without porosity were obtained. Microstructural and thermomechanical properties of products obtained by this method were systematically compared to those of some alloys elaborated by the ...

  12. Property enhancement by grain refinement of zinc-aluminium foundry alloys

    Science.gov (United States)

    Krajewski, W. K.; Greer, A. L.; Piwowarski, G.; Krajewski, P. K.

    2016-03-01

    Development of cast alloys with good mechanical properties and involving less energy consumption during their melting is one of the key demands of today's industry. Zinc foundry alloys of high and medium Al content, i.e. Zn-(15-30) wt.% Al and Zn-(8-12) wt.% Al, can satisfy these requirements. The present paper summarizes the work [1-9] on improving properties of sand-cast ZnAl10 (Zn-10 wt.% Al) and ZnAl25 (Zn-25 wt. % Al) alloys by melt inoculation. Special attention was devoted to improving ductility, whilst preserving high damping properties at the same time. The composition and structural modification of medium- and high-aluminium zinc alloys influence their strength, tribological properties and structural stability. In a series of studies, Zn - (10-12) wt. % Al and Zn - (25-26) wt.% Al - (1-2.5) wt.% Cu alloys have been doped with different levels of added Ti. The melted alloys were inoculated with ZnTi-based refiners and it was observed that the dendritic structure is significantly finer already after addition of 50 - 100 ppm Ti to the melted alloys. The alloy's structure and mechanical properties have been studied using: SEM (scanning electron microscopy), LM (light microscopy), dilatometry, pin-on-disc wear, and tensile strength measurements. Grain refinement leads to significant improvement of ductility in the binary high-aluminium Zn-(25-27) Al alloys while in the medium-aluminium alloys the effect is rather weak. In the ternary alloys Zn-26Al-Cu, replacing a part of Cu with Ti allows dimensional changes to be reduced while preserving good tribological properties. Furthermore, the high initial damping properties were nearly entirely preserved after inoculation. The results obtained allow us to characterize grain refinement of the examined high-aluminium zinc alloys as a promising process leading to the improvement of their properties. At the same time, using low melting ZnTi-based master alloys makes it possible to avoid the excessive melt overheating

  13. Optical Limiting Properties of Ag-Cu Metal Alloy Nanoparticles Analysis by using MATLAB

    International Nuclear Information System (INIS)

    Ag-Cu alloy nanoparticles were formed by sequential ion implantation (Ag and Cu) in silica using a metal vapor vacuum arc (MEVVA) ion source. Third-order nonlinear optical properties of the nanoparticles were measured at 1064 nm excitations using the Z-scan technique. Curve fitting analysis, based on the MATLAB features for Ag-Cu alloy nanoparticle optical limiting experiments, is used. The results show that Ag-Cu alloy nanoparticles display a refractive optical limiting effect at 1064nm. (condensed matter: structure, mechanical and thermal properties)

  14. MICROSTRUCTURE AND PROPERTIES OF ZL201 ALLOY OBTAINED BY NEAR-LIQUIDUS ELECTROMAGNETIC CASTING

    Institute of Scientific and Technical Information of China (English)

    P. Wang; L.F. Sh; G.M. Lu; J.Z. Cui

    2005-01-01

    The microstructures of ZL201 alloy slurry prepared by near-liquidus electromagnetic casting(NLEMC), electromagnetic casting(EMC), and near-liquidus casting(NLC) were investigated by means of electron microscopy and image analysis. Mechanical properties of as-cast alloys were determined. The results show that the NLEMC induces a fine, uniform, and equiaxed grain structure with a mean equal-area-circle grain diameter of 32.8μm. The as-cast alloy has a hardness of HV122.8 and a tensile strength of 368MPa. Both of them are better than those of the alloys prepared by EMC and by NLC. The mechanism of grain refinement in the NLEMC alloy slurry was discussed.

  15. Mechanical Properties of Refractory High Entropy Alloys Fabricated by Powder Processing

    Energy Technology Data Exchange (ETDEWEB)

    Kuk, Seoung Woo; Kim, Ki Hwan [Korea Atomic Energy Research Institute, Yuseong, Daejeon (Korea, Republic of); Lim, Woo Jin; Kang, Byung Chul; Hong, Soon Hyung; Ryu, Ho Jin [KAIST, Daejeon (Korea, Republic of)

    2015-10-15

    The effects of high configurational entropy, lattice distortion and sluggish diffusion are attributed to the distinguishable behavior of high entropy alloys. The structural applications of high entropy alloys are also promising in advanced nuclear energy systems for nuclear fission and fusion applications. Because of the randomly occupied lattice points by atoms with different atomic radius, lattice distortions and local atomic level strain were developed. The local lattice distortions influence the mechanical properties of high entropy alloys. The strengthening of high entropy alloys is attributed to the lattice distortions and local atomic level strain that increase the resistance to the dislocation motion. Some high entropy alloys exhibit remarkable irradiation resistance. Nagase et al. reported that the Conference alloy was irradiation resistant up to 40 dpa. Ega mi proposed that the irradiation defects can be self-healed because the recrystallization happens more easily in high entropy alloys. The mechanically alloyed and sintered samples have a much smaller grain size than that in cast high entropy alloys.

  16. Study on improved tribological properties by alloying copper to CP-Ti and Ti–6Al–4V alloy

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Song [Biomechanics and Biotechnology Lab, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057 (China); Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China); Ma, Zheng [Institute of Metal Research, Chinese Academy of Science, Shenyang 110016 (China); Liao, Zhenhua [Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China); Biomechanics and Biotechnology Lab, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057 (China); Song, Jian [State Key Laboratory of Tribology, Tsinghua University, Beijing 100084 (China); Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China); Yang, Ke [Institute of Metal Research, Chinese Academy of Science, Shenyang 110016 (China); Liu, Weiqiang, E-mail: weiqliu@hotmail.com [Biomechanics and Biotechnology Lab, Research Institute of Tsinghua University in Shenzhen, Shenzhen 518057 (China); State Key Laboratory of Tribology, Tsinghua University, Beijing 100084 (China)

    2015-12-01

    Copper alloying to titanium and its alloys is believed to show an antibacterial performance. However, the tribological properties of Cu alloyed titanium alloys were seldom studied. Ti–5Cu and Ti–6Al–4V–5Cu alloys were fabricated in the present study in order to further study the friction and wear properties of titanium alloys with Cu additive. The microstructure, composition and hardness were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM) and hardness tester. The tribological behaviors were tested with ZrO{sub 2} counterface in 25% bovine serum using a ball-on-disc tribo-tester. The results revealed that precipitations of Ti{sub 2}Cu intermetallic compounds appeared in both Ti–5Cu and Ti–6Al–4V–5Cu alloys. The tribological results showed an improvement in friction and wear resistance for both Ti–5Cu and Ti–6Al–4V–5Cu alloys due to the precipitation of Ti{sub 2}Cu. The results also indicated that both CP-Ti and Ti–5Cu behaved better wear resistance than Ti–6Al–4V and Ti–6Al–4V–5Cu due to different wear mechanisms when articulated with hard zirconia. Both CP-Ti and Ti–5Cu revealed dominant adhesive wear with secondary abrasive wear mechanism while both Ti–6Al–4V and Ti–6Al–4V–5Cu showed severe abrasive wear and cracks with secondary adhesive wear mechanism due to different surface hardness integrated by their microstructures and material types. - Highlights: • Ti–5Cu and Ti–6Al–4V–5Cu alloys were fabricated with Cu additive. • Precipitations of Ti{sub 2}Cu intermetallic compounds appeared after alloying Cu. • The precipitation of Ti{sub 2}Cu improved both friction and wear resistance. • Plowing was the dominant material removal force with severe plowing phenomenon. • Different dominant and secondary wear mechanisms appeared with different hardness.

  17. Microstructures and Mechanical Properties of Al/Mg Alloy Multilayered Composites Produced by Accumulative Roll Bonding

    Institute of Scientific and Technical Information of China (English)

    H.S.Liu; B.Zhang; G.P.Zhang

    2011-01-01

    Al/Mg alloy multilayered composites were produced successfully at the lower temperature (280℃) by accumulative roll bonding (ARB) processing technique. The microstructures of Al and Mg alloy layers were characterized by scanning electron microscopy and transmission electron microscopy. Vickers hardness and three-point bending tests were conducted to investigate mechanical properties of the composites. It is found that Vickers hardness, bending strength and stiffness modulus of the Al/Mg alloy multilayered composite increase with increasing the ARB pass. Delamination and crack propagation along the interface are the two main failure modes of the multilayered composite subjected to bending load. Strengthening and fracture mechanisms of the composite are analyzed.

  18. Parametric Analysis of Tensile Properties of Bimodal Al Alloys by Finite Element Method

    Institute of Scientific and Technical Information of China (English)

    W.L. Zhanga; S. Li; S.R. Nutt

    2009-01-01

    An axisymmetrical unit cell model was used to represent a bimodal Al alloy that was composed of both nano-grained (NG) and coarse-grained (CG) aluminum. Effects of microstructural and materials parameters on tensile properties of bimodal Al alloy were investigated by finite element method (FEM). The parameters analyzed included aspect ratios of CG Al and the unit cell, volume fraction of CG Al (VFCG), and yield strength and strain hardening exponent of CG Al. Aspect ratios of CG Al and the unit cell have no significant influence on tensile stress-strain response of the bimodal Al alloy. This phenomenon derives from the similarity in elastic modulus and coefficient of thermal expansion between CG Al and NG Al. Conversely, tensile properties of bimodal Al alloy are extremely sensitive to VFCG, yield strength and strain hardening exponent of CG Al.Specifically, as VFCG increases, both yield strength and ultimate tensile strength (UTS) of the bimodal Al alloy decreases, while uniform strain of bimodal Al alloy increases. In addition, an increase in yield strength of CG Al results in an increase in both yield stress and UTS of bimodal Al alloy and a decrease in uniform strain of bimodal Al alloy. The lower capability in lowering the increase of stress concentration in NG Al due to a higher yield strength of CG Al causes the lower uniform strain of the bimodal Al alloy. When strain hardening exponent of CG Al increases, 0.2% yield stress, UT5, and uniform strain of the bimodal Al alloy increases. This can be attributed to the increased work-hardening ability of CG Al with a higher strain hardening exponent.

  19. Stabilisation of mechanical properties in silver alloys by addition of lanthanides

    Directory of Open Access Journals (Sweden)

    W. Głuchowski

    2008-10-01

    Full Text Available Purpose: Silver alloys intended for industrial application should characterise by high electrical conductivity (as pure silver as well as high mechanical and functional properties, stable also at elevated temperature. The objective of this work was to investigate the mechanical properties stability of Ag-La (0.5% and Ag-mishmetal (1 and 4% alloys caused by severe plastic deformation compared to the Ag+(7.5 wt %Cu alloy and pure Ag materials.Design/methodology/approach: Tests were made with the samples obtained by casting and further plastic working included KOBO® extrusion process and drawing. Wires were annealed in temperature range 50 - 500°C. The mechanical properties (at room temperature, elevated temperature and after annealing and microstructure were examined. The values of yield strength obtained in a tension tests have been compared to the values calculated theoretically.Findings: Additive of rare earth metals contributed to fine structure obtaining, particles formed in grain boundaries stabilized microstructure at elevated temperature. Increase of mechanical properties of investigated alloys was connected with presence of fine precipitations in silver matrix, which confirmed susceptibility to precipitation hardening of silver – mishmetal alloys.Research limitations/implications: Ability of new alloys to precipitation hardening should be confirmed by further investigations, including solution heat treatment and ageing, also for materials prepared in vacuum furnace.Practical implications: Stability of mechanical properties at elevated temperature, gives possibility to use of new silver allays for producing elements designed to operate at elevated temperatures or exposed to rapid temperature changes. Increased mechanical properties and good tarnish resistance indicates possibility of new applications of investigated alloys in jewellery and medicine, after additional and essential investigations.Originality/value: The wire made from

  20. The influence of remelting on the properties of AlSi6Cu4 alloy modified by antimony

    Directory of Open Access Journals (Sweden)

    D. Medlen

    2012-01-01

    Full Text Available The paper deals with the problem of multiple remelting influence on AlSi6Cu4 alloy modified by antimony on chosen mechanical characteristics, microstructure and gas content. This foundry alloy is used mostly in automotive industry. Foundry Aluminum-Silicon alloys are also used in number of industrial weight sensitive applications because of their low weight and very good castability and good mechanical properties. Modifiers are usually added to molten aluminum-silicon alloys to refine the eutectic phase particle shape and improve the mechanical properties of the final cast products and Al-Si alloys cast properties.

  1. Enhancement in mechanical properties of a β-titanium alloy by high-pressure torsion

    Directory of Open Access Journals (Sweden)

    Katarzyna Sharman

    2015-01-01

    Full Text Available Titanium alloys, mainly Ti–6Al–4V, are commonly used in biomedical applications as orthopedic implants. Due to the potential toxic influence of V and Al cations on health, a new alloy composition, Ti–24Nb–4Zr–8Sn, was introduced. However, Ti–24Nb–4Zr–8Sn has a much lower tensile strength by comparison with the Ti–6Al–4V alloy. The aim of this research was to determine whether high-pressure torsion (HPT can be an efficient method for obtaining the desired properties in the case of the Ti–24Nb–4Zr–8Sn β-titanium alloy. This paper presents an analysis of the microstructural and mechanical properties of the Ti–24Nb–4Zr–8Sn alloy processed by HPT with various processing parameters. The obtained microstructures were examined using transmission electron microscopy (TEM. Mechanical properties, such as hardness and tensile strength, were also measured. The study demonstrates that HPT of the Ti–24Nb–4Zr–8Sn alloy leads to a significant reduction of grain size and this grain refinement gives a major improvement in tensile strength and hardness.

  2. DYNAMIC PROPERTIES OF AL-ALLOY FOAM BEAM DAMAGED BY COMPRESSIVE FATIGUE

    Institute of Scientific and Technical Information of China (English)

    Sung-Gaun Kim; Ilhyun Kim; Amkee Kim; Seung-Joon Kim; Junhong Park

    2008-01-01

    The permanent residual strain in aluminum (Al) alloy foams induced by compressive fatigue gradually increases with the increasing number of loading cycles.Consequently,the progressive shortening of Al-alloy foam degrades the dynamic material performance by the failure and ratcheting of multi-cells in the foam.In this paper,the dynamic properties of Al-alloy foams damaged by compressive fatigue were studied.The beam specimens with various residual strains were made by cyclic compression-compression stress.The dynamic bending modulus and loss factor were evaluated by using a beam transfer function method.As a result,the dynamic bending stiffness of Al-alloy foam turned out to be decreased due to damage while the loss factor was improved because of the increasing energy dissipation of such factors as cracked cell walls formed during the shortening process of the foam.The loss factor shows a manifest dependence on the fatigue residual strain.

  3. Atomic scale properties of magnetic Mn-based alloys probed by emission Mössbauer spectroscopy

    CERN Multimedia

    Mn-based alloys are characterized by a wealth of properties, which are of interest both from fundamental physics point of view and particularly attractive for different applications in modern technology: from magnetic storage to sensing and spin-based electronics. The possibility to tune their magnetic properties through post-growth thermal processes and/or stoichiometry engineering is highly important in order to target different applications (i.e. Mn$_{x}$Ga) or to increase their Curie temperature above room temperature (i.e. off-stoichiometric MnSi). In this project, the Mössbauer effect will be applied at $^{57}$Fe sites following implantation of radioactive $^{57}$Mn, to probe the micro-structure and magnetism of Mn-based alloys on the atomic-scale. The proposed experimental plan is devoted to establish a direct correlation between the local structure and bulk magnetism (and other physical properties) of Mn-based alloys.

  4. The influence of remelting on the properties of AlSi6Cu4 alloy modified by antimony

    OpenAIRE

    D. Medlen; D. Bolibruchova

    2012-01-01

    The paper deals with the problem of multiple remelting influence on AlSi6Cu4 alloy modified by antimony on chosen mechanical characteristics, microstructure and gas content. This foundry alloy is used mostly in automotive industry. Foundry Aluminum-Silicon alloys are also used in number of industrial weight sensitive applications because of their low weight and very good castability and good mechanical properties. Modifiers are usually added to molten aluminum-silicon alloys to refine the eut...

  5. TiNi Shape Memory Alloy Foams Synthesized by Spacer Sintering and their Properties

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Titanium (Ti) andnickel (Ni) elemental powders were blended by ball milling and the ball milled powders were employed to fabricate TiNi shape memory alloy (SMA) foams by spacer sintering. Effect of ball milling time on phase constitutes of the sintered TiNi alloy foams was studied by X-ray diffraction (XRD) analysis. Scanning electron microscopy (SEM) was used to characterize the porous structure, and compressive tests were carried out to evaluate the mechanical properties ofthe foams. Results indicate that porosities of the TiNi alloy foams can be controlled by using the spacer sintering method, and the porosities show a significant effect on the mechanical properties and shape memory effect (SME).

  6. Microstructure and Tensile Properties of Wrought Al Alloy 5052 Produced by Rheo-Squeeze Casting

    Science.gov (United States)

    Lü, Shulin; Wu, Shusen; Wan, Li; An, Ping

    2013-06-01

    The semisolid slurry of wrought Al alloy 5052 was prepared by the indirect ultrasonic vibration (IUV) method, in which the horn was vibrated under the outside of the metallic cup containing molten alloy, and then shaped by direct squeeze casting (SC). Spherical primary α-Al particles were uniformly dispersed in the matrix and presented a bimodal distribution of grain sizes. The effects of rheo-squeeze casting (RSC) parameters such as squeeze pressure and solid fraction on the microstructure and tensile properties of the semisolid alloy were investigated. The results indicate that average diameters of the primary α-Al particles decreased with the increase of squeeze pressure, while the tensile properties of the alloy increased. With the increase of solid fraction, the tensile strength increased first and then decreased, but the elongation decreased continuously. The best tensile properties were achieved when the slurry with a solid fraction of 0.17 solidified under 100 MPa. Compared to conventional squeeze casting, RSC process can offer the 5052 alloy better tensile strength and elongation, which were improved by 9.7 pct and 42.4 pct, respectively.

  7. Modifying structure and properties of nickel alloys by nanostructured composite powders

    Science.gov (United States)

    Cherepanov, A. N.; Ovcharenko, V. E.; Liu, G.; Cao, L.

    2015-01-01

    The article presents the results of an experimental study of the influence of powder nanomodifiers of refractory compounds on the mechanical properties, macro- and microstructure of heat-resistant alloys ZhS-6K and Inconel 718. It is shown that the introduction of nanomodifiers into the melt leads to the refinement of the alloy structure: the average grain size decreases 1.5-2 times, and their morphology becomes similar to equiaxial at significant reduction of the particle size in the carbide phase. The service life of ZhS-6K alloy under cyclic loading at 600°C increases 2.7 times, and at 975 °C by 40 %, and relative elongation increases more than twice. The mechanical properties of Inconel 718 significantly increase: long-term strength at 650 °C increases 1.5-2 times, and the number of cycles before the collapse at 482 °C grows more than three times. It has been found out that addition of nanomodifiers to the melt, in alloys, forms clusters of particles of refractory compounds at borders and joints of the formed grain structure that may help slowing down the processes of recrystallization (prevents the increase in the size of the contacting grains by their associations) and stabilizes the strength properties of the alloys at higher temperatures.

  8. Microstructure and properties of AZ80 magnesium alloy prepared by hot extrusion from recycled machined chips

    Institute of Scientific and Technical Information of China (English)

    刘英; 李元元; 张大童; 倪东惠; 陈维平

    2002-01-01

    AZ80 magnesium alloy was prepared by hot extrusion of recycled machined chips and its microstructure and mechanical properties were investigated. Hot pressing was employed to prepare extrusion billets of AZ80 chips, then the billets were hot extruded at 623K with an extrusion ratio of 25∶ 1. The extruded rods show a high ultimate tensile strength of 285MPa and a high elongation of 6%. Due to grain refinement by extrusion, mechanical properties of the extruded rods are much higher than those of as-cast AZ80 alloy. Process technique and chips densification mechanism were also studied. Results show that hot extrusion is an efficient method for AZ80 alloy chips recycling.

  9. Magnetic properties of doped Mn-Ga alloys made by mechanical milling and heat treatment

    Directory of Open Access Journals (Sweden)

    Daniel R. Brown

    2016-05-01

    Full Text Available Mn-Ga alloys have shown hard magnetic properties, even though these alloys contain no rare-earth metals. However, much work is needed before rare-earth magnets can be replaced. We have examined the magnetic properties of bulk alloys made with partial replacement of both the Mn and Ga elements in the Mn0.8Ga0.2 system. Bulk samples of Mn-Ga-Bi, Mn-Ga-Al, Mn-Fe-Ga and Mn-(FeB-Ga alloys were fabricated and studied using mechanically milling and heat treatments while altering the atomic percentage of the third element between 2.5 and 20 at%. The ternary alloy exhibits all hard magnetic properties at room temperature with large coercivity. Annealed Mn-Ga-X bulk composites exhibit high coercivities up to 16.6 kOe and remanence up to 9.8 emu/g, that is increased by 115% over the binary system.

  10. Microstructure and mechanical properties of AZ31 Mg alloy processed by high ratio extrusion

    Institute of Scientific and Technical Information of China (English)

    CHEN Yong-jun; WANG Qu-dong; LIN Jin-bao; ZHANG Lu-jun; ZHAI Chun-quan

    2006-01-01

    The microstructure and mechanical properties of AZ31 Mg alloy processed by high ratio extrusion (HRE) were investigated. General extrusion with extrusion ratio of 7 and high ratio extrusion with extrusion ratio 100 were contrastively conducted at 250, 300 and 350 ℃. The results show that HRE process may be applied successfully to AZ31 Mg alloy at temperatures of 250, 300 and 350 ℃ and this leads to obvious grain refinement during HRE process. The strength of HRE process is improved obviously compared with that of general extrusion. The grain refining mechanism of HRE process was also discussed. The current results imply that the simple high ratio extrusion method might be a feasible and effective processing means for refining the microstructure and improving the mechanical properties of AZ31 Mg alloy.

  11. Microstructural evolution and mechanical properties of hypereutectic Al–Si alloy processed by liquid die forging

    Indian Academy of Sciences (India)

    F F Wu; S T Li; G A Zhang; F Jiang

    2014-08-01

    The microstructural evolution and mechanical properties of a hypereutectic Al–Si alloy processed by liquid die forging were investigated. It is found that the grain size of the primary Si was significantly reduced by liquid die forging with increased pressure. The volume fraction of eutectic silicon was decreased with increased pressure. By liquid die forging with pressure up to 180 MPa, the average size of the primary Si was reduced to about 18 m, which results in the remarkable increase in the fracture strength and hardness of the hypereutectic Al–Si alloy.

  12. Microstructure and mechanical properties of hypereutectic Al-Fe alloys prepared by semi-solid formation

    Directory of Open Access Journals (Sweden)

    Liu Bo

    2011-11-01

    Full Text Available The effects of alloying elements, electromagnetic stirring, reheating and semi-solid formation on the microstructure and mechanical properties of Al-Fe alloys prepared by semi-solid formation were studied. It was found that alloying elements and electromagnetic stirring can alter the morphology and growth mode of the iron-rich phase in Al-Fe alloys; and effectively refine the primary Al3Fe phase. In contrast to the microstructure obtained in conventional casting, the Al3Fe phase becomes thin short rod-like instead of thick needle-like; and the dendritic grain structure almost disappears in the semi-solid formation. The Al3Fe phase can be further refined through being dissolved or fused during subsequent reheating. It was also found that the larger extrusion ratio of semi-solid formation causes a greater crushing effect and therefore the Al3Fe phase is more refined and has more uniform distribution. Moreover, Al-Fe alloys prepared by semi-solid formation exhibit excellent mechanical properties at both room and high temperatures.

  13. Structure and properties of surface layers obtained by alloying of the hot work tool steels

    OpenAIRE

    L.A. Dobrzański; A. Polok; E. Jonda

    2006-01-01

    Purpose: The aim of the present work was to study the microstructure and properties produced after laser alloying of the 55NiCrMoV7 and X40CrMoV5-1 an alloy hot-work tool steels.Design/methodology/approach: Structure investigation was performed using the light microscope Leica MEF4A supplied by Zeiss. Phase composition and crystallographic structure were determined by the X-ray diffraction method using the DRON 2.0. The measurements of microhardness have been performed using Shimadzu microhar...

  14. Elastic properties of Nb-based alloys by using the density functional theory

    Institute of Scientific and Technical Information of China (English)

    Liu Zeng-Hui; Shang Jia-Xiang

    2012-01-01

    A first-principles density functional approach is used to study the electronic and the elastic properties of Nb15X (X =Ti,Zr,Hf,V,Ta,Cr,Mo,and W) alloys.The elastic constants c11 and c12,the shear modulus C′,and the elastic modulus E〈100〉 are found to exhibit similar tendencies,each as a function of valence electron number per atom (EPA),while c44 seems unclear.Both c11 and c12 of Nb15X alloys increase monotonically with the increase of EPA.The C′ and E〈100〉 also show similar tendencies.The elastic constants (except c44) increase slightly when alloying with neighbours of a higher d-transition series.Our results are supported by the bonding density distribution.When solute atoms change from Ti(Zr,Hf) to V(Ta) then to Cr(Mo,W),the bonding electron density between the central solute atom and its first neighbouring Nb atoms is increased and becomes more anisotropic,which indicates the strong interaction and thus enhances the elastic properties of Nb-Cr(Mo,W) alloys.Under uniaxial (100) tensile loading,alloyed elements with less (more) valence electrons decrease (increase) the ideal tensile strength.

  15. Corrosion and mechanical properties of AM50 magnesium alloy after being modified by 1 wt.% rare earth element gadolinium

    Institute of Scientific and Technical Information of China (English)

    杨淼; 刘耀辉; 刘家安; 宋雨来

    2014-01-01

    In order to improve the corrosion and mechanical properties of AM50 magnesium alloy, 1 wt.% Gd was used to modify the AM50 magnesium alloy. The microstructure, corrosion and mechanical properties were evaluated by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), electrochemical and mechanical stretch methods. The results indicated that β-Mg17Al12 phase decreased and Al2Gd3 and Al0.4GdMn1.6 phase existed after Gd addition. Because of the Gd addition, the grain of AM50 magnesium alloy was refined significantly, which improved the tensile strength of AM50 magnesium al-loy. The decreasing ofβ phase improved the corrosion resistance of the magnesium alloy. The fracture mechanism of the Gd modified AM50 magnesium alloy was quasi-cleavage fracture. The corrosion residual strength (CRS) of AM50 magnesium alloy was im-proved after 1 wt.% Gd addition.

  16. Fatigue properties of magnesium alloy AZ91 processed by severe plastic deformation.

    Science.gov (United States)

    Fintová, Stanislava; Kunz, Ludvík

    2015-02-01

    Fatigue properties of cast AZ91 magnesium alloy processed by severe plastic deformation were investigated and compared with the properties of the initial cast state. The severe plastic deformation was carried out by equal channel angular pressing (ECAP). The ECAP treatment resulted in a bimodal structure. The bimodality consists in a coexistence of fine grained areas with higher content of Mg17Al12 particles and areas exhibiting larger grains and lower density of Mg17Al12 particles. Improvement of the basic mechanical properties of AZ91 (yield stress, tensile strength and ductility) by ECAP was significant. Also the improvement of the fatigue life in the low-cycle fatigue region was substantial. However the improvement of the fatigue strength in the high-cycle fatigue region was found to be negligible. The endurance limit based on 10(7) cycles for the cast alloy was 80 MPa and for the alloy processed by ECAP 85 MPa. The cyclic plastic response in both states was qualitatively similar; initial softening was followed by a long cyclic hardening. Fatigue cracks in cast alloy initiate in cyclic slip bands which were formed in areas of solid solution. In the case of severe plastic deformed material with bimodal structure two substantially different mechanisms of crack initiation were observed. Crack initiation in slip bands was a preferred process in the areas with large grains whereas the grain boundaries cracking was a characteristic mechanism in the fine grained regions. PMID:25498295

  17. Microstructures and mechanical properties of AZ91D magnesium alloy processed by low pressure die casting

    Institute of Scientific and Technical Information of China (English)

    JIANG Hai-yan; FU Peng-huai; YU Yan-dong; ZHAI Chun-quan

    2006-01-01

    AZ91D alloy components were cast by low pressure die casting (LPDC) process. The mechanical properties of cast components with different microstructural features (shrinkage and distribution of Mg17Al12 second phase) were investigated under as-cast states. Compared with gravity casting, AZ91D with LPDC has much coarser grain size and second phases(Mg17Al12 and Al8Mn5). The different size and distribution of Mg17Al12 phase and shrinkage correspond to different mechanical properties. The ultimate tensile strengths and elongations are mainly decided by the content and distribution of shrinkage porosity, while the yield strengths are determined by the percentage and distribution of Mg17Al12 phase. The more and finer Mg17Al12 phase in the alloy, the relatively higher the yield strengths are. In the alloy without shrinkage, the mechanical properties are mainly determined by the size and distribution of Mg17Al12 phase. The finer Mg17Al12 phase, the better the mechanical properties are. Under optimal process, the density and mechanical properties of LPDC AZ91D are improved with fine microstructures.

  18. Optical Limiting Properties of Ag-Cu Metal Alloy Nanoparticles Analysis by using MATLAB

    Institute of Scientific and Technical Information of China (English)

    WANG Yu-Hua; LI Hui-Qing; LU Jian-Duo; WANG Ru-Wu

    2011-01-01

    Ag-Cu alloy nanoparticles were formed by sequential ion implantation (Ag and Cu) in silica using a metal vapor vacuum arc (MEVVA) ion source.Third-order nonlinear optical properties of the nanoparticles were measured at 1064nm excitations using the Z-scan technique.Curve fitting analysis,based on the MATLAB features for Ag-Cu alloy nanoparticle optical limiting experiments,is used.The results show that Ag-Cu alloy nanoparticles display a refractive optical limiting effect at 1064 nm.Recently,increasing attention has been focused on the third-order nonlinear susceptibility and the photorefractive effect of noble-metal clusters embedded in dielectric matrices.[1-3] Third-order nonlinearities of metal/dielectric composite materials are influenced not only by the type and size of the embedded metal clusters,but also by the dielectric constant,thermal conductivity and heat capacity of the dielectric matrices.[4-6] Amongst the nanoparticles studied earlier,high nonlinear absorption and nonlinear refraction coefficients were found in copper and copper containing nanomaterials.[7,8] For silver,the nonlinear refractive index γ changes from positive to negative upon the growth of clusters.[9] Potential applications of optical limiters in the protection of sensors from intense laser pulses have motivated great efforts to design new nonlinear optical systems.[10]%Ag-Cu alloy nanoparticles were formed by sequential ion implantation (Ag and Cu) in silica using a metal vapor vacuum arc (MEVVA) ion source. Third-order nonlinear optical properties of the nanoparticles were measured at 1064 nm excitations using the Z-scan technique. Curve fitting analysis, based on the MATLAB features for Ag-Cu alloy nanoparticle optical limiting experiments, is used. The results show that Ag-Cu alloy nanoparticles display a refractive optical limiting effect at 1064 nm.

  19. Properties of WZ21 (%wt) alloy processed by a powder metallurgy route.

    Science.gov (United States)

    Cabeza, Sandra; Garcés, Gerardo; Pérez, Pablo; Adeva, Paloma

    2015-06-01

    Microstructure, mechanical properties and corrosion behaviour of WZ21 (%wt) alloy prepared by a powder metallurgy route from rapidly solidified powders have been studied. Results were compared to those of the same alloy prepared through a conventional route of casting and extrusion. The microstructure of the extruded ingot consisted of α-Mg grains and Mg3Zn3Y2 (W-phase) and LPSO-phase particles located at grain boundaries. Moreover, stacking faults were also observed within α-Mg grains. The alloy processed by the powder metallurgy route exhibited a more homogeneous and finer microstructure, with a grain size of 2 μm. In this case W-phase and Mg24Y5 phase were identified, but not the LPSO-phase. The microstructural refinement induced by the use of rapidly solidified powders strengthened the alloy at room temperature and promoted superplasticity at higher strain rates. Corrosion behaviour in PBS medium evidenced certain physical barrier effect of the almost continuous arrangements of second phases aligned along the extrusion direction in conventionally processed WZ21 alloy, with a stable tendency around 7 mm/year. On the other hand, powder metallurgy processing promoted significant pitting corrosion, inducing accelerated corrosion rate during prolonged immersion times. PMID:25792409

  20. Properties of WZ21 (%wt) alloy processed by a powder metallurgy route.

    Science.gov (United States)

    Cabeza, Sandra; Garcés, Gerardo; Pérez, Pablo; Adeva, Paloma

    2015-06-01

    Microstructure, mechanical properties and corrosion behaviour of WZ21 (%wt) alloy prepared by a powder metallurgy route from rapidly solidified powders have been studied. Results were compared to those of the same alloy prepared through a conventional route of casting and extrusion. The microstructure of the extruded ingot consisted of α-Mg grains and Mg3Zn3Y2 (W-phase) and LPSO-phase particles located at grain boundaries. Moreover, stacking faults were also observed within α-Mg grains. The alloy processed by the powder metallurgy route exhibited a more homogeneous and finer microstructure, with a grain size of 2 μm. In this case W-phase and Mg24Y5 phase were identified, but not the LPSO-phase. The microstructural refinement induced by the use of rapidly solidified powders strengthened the alloy at room temperature and promoted superplasticity at higher strain rates. Corrosion behaviour in PBS medium evidenced certain physical barrier effect of the almost continuous arrangements of second phases aligned along the extrusion direction in conventionally processed WZ21 alloy, with a stable tendency around 7 mm/year. On the other hand, powder metallurgy processing promoted significant pitting corrosion, inducing accelerated corrosion rate during prolonged immersion times.

  1. Improvement of mechanical properties and corrosion resistance of biodegradable Mg–Nd–Zn–Zr alloys by double extrusion

    International Nuclear Information System (INIS)

    Highlights: ► Microstructure of Mg–Nd–Zn–Zr alloys was refined and homogenized by double extrusion process. ► The mechanical properties of the alloys were significantly enhanced by double extrusion. ► The biocorrosion resistance of the alloys was improved by double extrusion. - Abstract: Mg–Nd–Zn–Zr alloy is a novel and promising biodegradable magnesium alloy due to good biocompatibility, desired uniform corrosion mode and outstanding corrosion resistance in simulated body fluid (SBF). However, the corrosion resistance and mechanical properties should be improved to meet the requirement of the biodegradable implants, such as plates, screws and cardiovascular stents. In the present study, double extrusion process was adopted to refine microstructure and improve mechanical properties of Mg–2.25Nd–0.11Zn–0.43Zr and Mg–2.70Nd–0.20Zn–0.41Zr alloys. The corrosion resistance of the alloys after double extrusion was also studied. The results show that the microstructure of the alloys under double extrusion becomes much finer and more homogeneous than those under once extrusion. The yield strength, ultimate tensile strength and elongation of the alloys under double extrusion are over 270 MPa, 300 MPa and 32%, respectively, indicating that outstanding mechanical properties of Mg–Nd–Zn–Zr alloy can be obtained by double extrusion. The results of immersion experiment and electrochemical measurements in SBF show that the corrosion resistance of Alloy 1 and Alloy 2 under double extrusion was increased by 7% and 8% respectively compared with those under just once extrusion.

  2. Improvement of mechanical properties and corrosion resistance of biodegradable Mg-Nd-Zn-Zr alloys by double extrusion

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiaobo, E-mail: xbxbzhang2003@163.com [School of Materials Science and Engineering, Nanjing Institute of Technology, Nanjing, 211167 (China); Wang, Zhangzhong [School of Materials Science and Engineering, Nanjing Institute of Technology, Nanjing, 211167 (China); Yuan, Guangyin [National Engineering Research Center of Light Alloy Net Forming, Shanghai Jiao Tong University, Shanghai, 200240 (China); Xue, Yajun [School of Materials Science and Engineering, Nanjing Institute of Technology, Nanjing, 211167 (China)

    2012-08-01

    Highlights: Black-Right-Pointing-Pointer Microstructure of Mg-Nd-Zn-Zr alloys was refined and homogenized by double extrusion process. Black-Right-Pointing-Pointer The mechanical properties of the alloys were significantly enhanced by double extrusion. Black-Right-Pointing-Pointer The biocorrosion resistance of the alloys was improved by double extrusion. - Abstract: Mg-Nd-Zn-Zr alloy is a novel and promising biodegradable magnesium alloy due to good biocompatibility, desired uniform corrosion mode and outstanding corrosion resistance in simulated body fluid (SBF). However, the corrosion resistance and mechanical properties should be improved to meet the requirement of the biodegradable implants, such as plates, screws and cardiovascular stents. In the present study, double extrusion process was adopted to refine microstructure and improve mechanical properties of Mg-2.25Nd-0.11Zn-0.43Zr and Mg-2.70Nd-0.20Zn-0.41Zr alloys. The corrosion resistance of the alloys after double extrusion was also studied. The results show that the microstructure of the alloys under double extrusion becomes much finer and more homogeneous than those under once extrusion. The yield strength, ultimate tensile strength and elongation of the alloys under double extrusion are over 270 MPa, 300 MPa and 32%, respectively, indicating that outstanding mechanical properties of Mg-Nd-Zn-Zr alloy can be obtained by double extrusion. The results of immersion experiment and electrochemical measurements in SBF show that the corrosion resistance of Alloy 1 and Alloy 2 under double extrusion was increased by 7% and 8% respectively compared with those under just once extrusion.

  3. IMPROVING THE SURFACE PROPERTY OF TC4 ALLOY BY LASER NITRIDING AND ITS MECHANISM

    Institute of Scientific and Technical Information of China (English)

    Y.L. Yang; G.J. Zhao; D. Zhang; C.S. Liu

    2006-01-01

    The mixing technology of laser and heated nitrogen was applied to improve the surface hardaccelerate the nitriding process. Some interested samples were tested with XRD method (X-ray diffraction) to analyze the composition of nitrides, and the surface hardness of HV was measured.The results show that TiN and Ti2N were formed on the surface of Ti alloy with proper nitriding parameters, but TiN is the main composition. The surface hardness increased by three times, which sidered mainly of the activation of nitrogen by laser power and the pre-heated process which accelerated the nitriding process. The nitridation process can be considered as six steps given in detail. The result by analyzing the mechanism of improving the surface property of TiAl alloy shows the improvement of surface property due to two factors: the first reason is the result of laser annealing, and the second one is the formation of TiN.

  4. Nanostructure and related mechanical properties of an Al-Mg-Si alloy processed by severe plastic deformation

    OpenAIRE

    Nurislamova, Gulnaz; Sauvage, Xavier; Murashkin, Maxim; Islamgaliev, Rinat; Valiev, Ruslan

    2008-01-01

    Microstructural features and mechanical properties of an Al-Mg-Si alloy processed by high-pressure torsion have been investigated using transmission electron microscopy, X-ray diffraction, three-dimensional atom probe, tensile tests and microhardness measurements. It is shown that HPT processing of the Al-Mg-Si alloy leads to a much stronger grain size refinement than of pure aluminium (down to 100 nm). Moreover, massive segregation of alloying elements along grain boundaries is observed. Thi...

  5. Structure-Properties of PPE Alloy by Reactive Blending

    Science.gov (United States)

    Furuta, Motonobu; Koyama, Yoshio; Inoue, Takashi

    Poly(phenylene ether) (PPE) is a high temperature polymer (Tg=210°C). Neat PPE is hardly melt-processed below its thermal decomposition temperature. It is believed that the melt-processability is only achieved by blending with polystyrene as a polymeric plasticizer. The polymeric plasticizer sacrifices the heat resistance; the Tg decreases almost linearly with polystyrene content. We found that PPE can react with poly(ethylene-co-glycidylmethacrylate) (EGMA) by melt mixing. Reactive blending of PPE with EGMA yielded an excellent engineering plastic with nice melt-processability, even when a small amount of EGMA (e.g., 5 wt%) was incorporated. The injection molded parts showed high impact strength, high temperature resistance, high tensile strength, and low dielectric loss. It can be classified as a super-engineering plastics. The computer simulation based on a particle-slip model revealed why the melt-processability is attained by the incorporation of polyolefin in pure PPE matrix.

  6. Microstructure and Mechanical Properties of Hyper-eutectic Al-Si Alloys Fabricated by Spray Casting

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Microstructure and mechanical properties of hyper-eutectic Al-Si alloy fabricated by spray casting were investigated and then these results were compared with those by squeeze cast. The spray-cast specimen was found to have finer Si particles (~5μm) compared to the squeeze-cast specimen (10-25μm). The tensile strength and elongation of the spray-cast specimen are also higher than those of the squeeze cast one. It was considered that the increased mechanical properties of the spray-cast specimen were mainly due to finer size of the Si particles distributed in Al matrix.

  7. Microstructures and mechanical properties of AZ80 alloy treated by pulsed ultrasonic vibration

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Pulsed ultrasonic field was employed in the melt of the AZ80 magnesium alloy. The effects of pulsed ultrasonic field on mierostructure and mechanical properties of AZ80 magnesium alloy were investigated. The results show that the as-cast mierostructure of the AZ80 alloy with pulsed ultrasonic treatment is significantly changed. Pulsed ultrasonic field significantly decreases the grain size, changes the morphologies of the β-Mg17Al12 phases and reduces their area fraction. It is found that pulse width of ultrasonic plays an important role on the microstrueture formation of AZ80 alloy. With increasing pulse width, grains beeome finer and more uniform. In the range of experimental parameters, the optimum pulse width for melt treatment process is found to be 210 μs. The mechanical tests show that the mechanical properties of the as-cast AZ80 magnesium alloy with pulsed ultrasonic treatment are much higher than those of AZ80 alloy without ultrasonic field.

  8. Structure and properties of surface layers obtained by alloying of the hot work tool steels

    Directory of Open Access Journals (Sweden)

    L.A. Dobrzański

    2006-04-01

    Full Text Available Purpose: The aim of the present work was to study the microstructure and properties produced after laser alloying of the 55NiCrMoV7 and X40CrMoV5-1 an alloy hot-work tool steels.Design/methodology/approach: Structure investigation was performed using the light microscope Leica MEF4A supplied by Zeiss. Phase composition and crystallographic structure were determined by the X-ray diffraction method using the DRON 2.0. The measurements of microhardness have been performed using Shimadzu microhardness intender equipped with electronic sensor that allows the direct readout of the hardness values.Findings: The metallographic investigations on light microscope show that steel after laser remelting can be characterized by a dendrite structure. Metallographic examinations on the scanning microscope with the EDX attachment confirm the occurrence of the niobium carbides in the surface layer of the investigated steels.Research limitations/implications: In order to evaluate with more detail the possibility of applying these surface layers in tools, further investigations should be concentrated on the determination of the thermal fatigue resistance of the layers.Practical implications: The surface layer of the hot work steel alloyed with ceramic powder have good properties and make possibility for uses it in various technical and industrial applications.Originality/value: The microstructure and properties of the surface layer of the 55NiCrMoV7 and X40CrMoV5-1 hot-work tool steels alloying with ceramic powder were compared.

  9. Microstructure and mechanical properties of magnesium alloy prepared by lost foam casting

    Institute of Scientific and Technical Information of China (English)

    TIAN Xue-feng; FAN Zi-tian; HUANG Nai-yu; WU He-bao; DONG Xuan-pu

    2005-01-01

    The microstructure and mechanical properties of AZ91 alloy prepared by lost foam casting(LFC) and various heat treatments have been investigated.The microstructure of the AZ91 alloy via LFC consists of dominant α-Mg and β-Mg17Al12 as well as a new phase Al32 Mn25 with size of about 5-50 μm,which has not been detected in AZ91 alloy prepared by other casting processes.The tests demonstrate that the as-cast mechanical properties are higher than those of sand gravity casting because of chilling and cushioning effect of foam pattern during the mould filling.The solution kinetics and the aging processes at different temperatures were also investigated by hardness and electrical resistivity measurements.The kinetics of aging are faster at the high temperature due to enhanced diffusion of atoms in the matrix,so the hardness peak at 380 ℃ occurs after 10 h;while at the lower aging temperature(150 ℃),the peak is not reached in the time(24 h) considered.

  10. Stress-Corrosion Cracking Property of Aluminum-Magnesium Alloy Processed by Equal-Channel Angular Pressing

    OpenAIRE

    Hiroaki Nakano; Satoshi Oue; Seiji Taguchi; Shigeo Kobayashi; Zenji Horita

    2012-01-01

    Stress-corrosion cracking property of an aluminum-magnesium alloy processed by equal-channel angular pressing (ECAP) was investigated by a slow strain-rate tensile technique in a 3% NaCl solution of pH 4.2 at 303 K. The maximum stress and elongation of the Al-Mg alloy were lower in the NaCl solution than in air. The stress-corrosion cracking property was evaluated by the decrease ratio of maximum stress and elongation of the Al-Mg alloy with NaCl solution, ( m a x ) and ( ) , respecti...

  11. Evaluation of Microstructure and Mechanical Properties of Nano-Y2O3-Dispersed Ferritic Alloy Synthesized by Mechanical Alloying and Consolidated by High-Pressure Sintering

    Science.gov (United States)

    Karak, Swapan Kumar; Dutta Majumdar, J.; Witczak, Zbigniew; Lojkowski, Witold; Ciupiński, Łukasz; Kurzydłowski, K. J.; Manna, Indranil

    2013-06-01

    In this study, an attempt has been made to synthesize 1.0 wt pct nano-Y2O3-dispersed ferritic alloys with nominal compositions: 83.0 Fe-13.5 Cr-2.0 Al-0.5 Ti (alloy A), 79.0 Fe-17.5 Cr-2.0 Al-0.5 Ti (alloy B), 75.0 Fe-21.5 Cr-2.0 Al-0.5 Ti (alloy C), and 71.0 Fe-25.5 Cr-2.0 Al-0.5 Ti (alloy D) steels (all in wt pct) by solid-state mechanical alloying route and consolidation the milled powder by high-pressure sintering at 873 K, 1073 K, and 1273 K (600°C, 800°C, and 1000°C) using 8 GPa uniaxial pressure for 3 minutes. Subsequently, an extensive effort has been undertaken to characterize the microstructural and phase evolution by X-ray diffraction, scanning and transmission electron microscopy, and energy dispersive spectroscopy. Mechanical properties including hardness, compressive strength, Young's modulus, and fracture toughness were determined using micro/nano-indentation unit and universal testing machine. The present ferritic alloys record extraordinary levels of compressive strength (from 1150 to 2550 MPa), Young's modulus (from 200 to 240 GPa), indentation fracture toughness (from 3.6 to 15.4 MPa√m), and hardness (from13.5 to 18.5 GPa) and measure up to 1.5 through 2 times greater strength but with a lower density (~7.4 Mg/m3) than other oxide dispersion-strengthened ferritic steels (ferritic matrix useful for grain boundary pinning and creep resistance.

  12. Structure and properties of ceramic coatings formed on aluminum alloys by microarc oxidation

    Institute of Scientific and Technical Information of China (English)

    LIU Wan-hui; BAO Ai-lian; LIU Rong-xiang; WU Wan-liang

    2006-01-01

    The thick and hard ceramic coatings were deposited on 2024 Al alloy by microarc oxidation in the electrolytic solution.Microstructure, phase composition and wear resistance of the oxide coatings were investigated by SEM, XRD and friction and wear tester. The microhardness and thickness of the oxide coatings were measured. The results show that the ceramic coating is mainly composed of α-Al2O3 and γ-Al2O3. During oxidation, the temperature in the microarc discharge channel is very high to make the local coating molten. From the surface to interior of the coating, microhardness increases gradually. The microhardness of the ceramic coating is HV1 800, and the microarc oxidation coatings greatly improve the antiwear properties of aluminum alloys.

  13. Tribological Properties of Aluminum Alloy treated by Fine Particle Peening/DLC Hybrid Surface Modification

    Directory of Open Access Journals (Sweden)

    Nanbu H.

    2010-06-01

    Full Text Available In order to improve the adhesiveness of the DLC coating, Fine Particle Peening (FPP treatment was employed as pre-treatment of the DLC coating process. FPP treatment was performed using SiC shot particles, and then AA6061-T6 aluminum alloy was DLC-coated. A SiC-rich layer was formed around the surface of the aluminum alloy by the FPP treatment because small chips of shot particles were embedded into the substrate surface. Reciprocating sliding tests were conducted to measure the friction coefficients. While the DLC coated specimen without FPP treatment showed a sudden increase in friction coefficient at the early stage of the wear cycles, the FPP/DLC hybrid treated specimen maintained a low friction coefficient value during the test period. Further investigation revealed that the tribological properties of the substrate after the DLC coating were improved with an increase in the amount of Si at the surface.

  14. Microstructure and corrosion property of AZ61 magnesium alloy by electromagnetic stirring

    Institute of Scientific and Technical Information of China (English)

    FANG Can-feng; ZHANG Xing-guo; JI Shou-hua; JIN Jun-ze; CHANG Yu-bao

    2005-01-01

    The influence of permanent-magnet-driven stirring during solidification on the microstructure and corrosion property of AZ61 magnesium alloy was investigated. The corrosion behaviour of AZ61 was studied in 3.5mol/L NaCl by measuring electrochemical polarization. The results show that the permanent-magnet stirring refines the microstructure of AZ61 magnesium alloy, which improves the precipitation amount and distribution uniformity of β phase and decreases the content of hydrogen, but it has less influence on the distribution uniformity of Zn. The change of precipitation amount of β phase influences the corrosive nature of the matrix, and it has no direct proportion with the corrosion resistance of the matrix.

  15. The effect of mechanical alloying on microstructure and mechanical properties of MoSi2 prepared by spark plasma sintering

    International Nuclear Information System (INIS)

    Highlights: • Powders of Mo and Si according to MoSi2 stoichiometry were mechanically alloyed. • The as milled powder mixture was sintered using spark plasma sintering. • We investigated the microstructure and mechanical properties of samples. - Abstract: In this research the effect of mechanical alloying on the in situ synthesis–sintering behavior and mechanical properties of MoSi2 has been investigated. The Mo and Si powders according to MoSi2 stoichiometric composition were mechanically alloyed at different times. Then, the powders were subjected to spark plasma sintering process for preparing monolithic MoSi2. X-ray diffraction pattern of the sintered samples showed that by increasing the mechanical alloying time, Mo5Si3 has been formed. It seems that the formation of Mo5Si3 is due to the effect of mechanical alloying on microstructure and thermodynamic condition of the reaction

  16. Effects on mechanical properties in electron beam welding of TC4 alloy by laser shock processing

    Institute of Scientific and Technical Information of China (English)

    LU Jinzhong; ZHANG Yongkang; KONG Dejun; REN Xudong; GE Tao; ZOU Shikun

    2007-01-01

    The surface of TC4 titanium alloy welding line by electron beam welding (EBW) was processed by high power Q-switched and repetition-rate Nd: glass laser. Effects of laser power and spot diameter on residual stress and microhardness of the TC4 alloy welding line by laser shock processing (LSP) have been analyzed. Results show that residual stresses almost do not change as laser poweris 45.9 J,spot diameter is φ9 mm; While laser power is 45.9 J, spot diameter less than φ3 mm, the distribution of residual stress in welding line occurs obvious variation, which residual stress increase obviously with spot diameter decrease. When power density is bigger than 1.8×1010W/cm2, residual stresses of electron beam welding line occur change by LSP,which improve obviously residual stress distribution; while laser power is bigger than 1.2×1010W/cm2, the surface micro-hardness of electron beam welding line occurs change by LSP, which improve obviously micro-hardness distribution. Mechanical properties of TC4 titanium alloy welding line will be improved by LSP, which provides experimental foundation for further controlling the distributions of residual stress and micro-hardness during laser shock processing.

  17. Interfacial Microstructure and Mechanical Properties of Al Alloy/Mg Alloy Laminated Composite Plates Fabricated by Equal Channel Angular Processing

    Institute of Scientific and Technical Information of China (English)

    LI Guorui; ZHAO Dong; ZHAO Yaojiang; ZHOU Bin; WANG Hongxia

    2016-01-01

    KAl (7075) alloy /Mg (AZ31) alloy laminated composite plates were successfully fabricated by the equal channel angular processing (ECAP) by using route A for 1, 2, and 3 passes at 573 K, respectively. After fabrication, the 1-pass ECAPed laminated composite plates were annealed at different temperatures. The microstructure evolution, phase constituent, and bonding strength near the joining interface of Al (7075) alloy /Mg (AZ31) alloy laminated composites plates were evaluated with scanning electron microscopy, X-ray diffraction, and shear tests. The experimental results indicated that a 20 μm diffusion layer was observed at the joining interface of Al (7075) alloy /Mg (AZ31) alloy laminated composites plates fabricated by the 1-pass ECAP, which mainly included Al3Mg2 and Mg17Al12 phases. With the increase of passes, the increase of diffusion layer thickness was not obvious and the form of crack in these processes led to the decrease of bonding strength. For 1-pass ECAPed composites, the thickness of diffusion layer remained unchanged after annealed at 473 K, while the bonding strength reached its maximum value 29.12 MPa. However, after elevating heat treatment temperature to 573 K, the thickness of diffusion layer increased rapidly, and thus the bonding strength decreased.

  18. Microstructures and Mechanical Properties of Co-Cr Dental Alloys Fabricated by Three CAD/CAM-Based Processing Techniques

    Directory of Open Access Journals (Sweden)

    Hae Ri Kim

    2016-07-01

    Full Text Available The microstructures and mechanical properties of cobalt-chromium (Co-Cr alloys produced by three CAD/CAM-based processing techniques were investigated in comparison with those produced by the traditional casting technique. Four groups of disc- (microstructures or dumbbell- (mechanical properties specimens made of Co-Cr alloys were prepared using casting (CS, milling (ML, selective laser melting (SLM, and milling/post-sintering (ML/PS. For each technique, the corresponding commercial alloy material was used. The microstructures of the specimens were evaluated via X-ray diffractometry, optical and scanning electron microscopy with energy-dispersive X-ray spectroscopy, and electron backscattered diffraction pattern analysis. The mechanical properties were evaluated using a tensile test according to ISO 22674 (n = 6. The microstructure of the alloys was strongly influenced by the manufacturing processes. Overall, the SLM group showed superior mechanical properties, the ML/PS group being nearly comparable. The mechanical properties of the ML group were inferior to those of the CS group. The microstructures and mechanical properties of Co-Cr alloys were greatly dependent on the manufacturing technique as well as the chemical composition. The SLM and ML/PS techniques may be considered promising alternatives to the Co-Cr alloy casting process.

  19. Microstructure and tensile properties of magnesium alloy modified by Si/Ca based refiner

    Institute of Scientific and Technical Information of China (English)

    DUAN Zhi-chao; SUN Yang-shan; WEI Yu; DU Wen-wen; XUE Feng; ZHU Tian-bai

    2005-01-01

    Microstructure and mechanical properties of pure magnesium and AZ31 alloy with Ca/Si based refiner addition were investigated. The results indicate that addition of Ca/Si based refiners to pure magnesium and AZ31 alloy results in remarkable microstructure refinement. With proper amount of refiner addition, the grain size in as cast ingots can be one order of magnitude lower than that without refiner addition. Small amount of refiner addition to AZ31 alloy increases both ultimate strength and yield strength significantly, while the ductility of the alloy with refiner addition is similar to that without refiner addition. Addition of refiner improves the deformability of AZ31 alloy and extruded or hot rolled specimens (rods or sheets) with refiner addition exhibit higher surface quality and mechanical properties than those without refiner addition.

  20. Metallurgical Mechanisms Controlling Mechanical Properties of Aluminum Alloy 2219 Produced by Electron Beam Freeform Fabrication

    Science.gov (United States)

    Domack, Marcia S.; Tainger, Karen M.

    2006-01-01

    The electron beam freeform fabrication (EBF3) layer-additive manufacturing process has been developed to directly fabricate complex geometry components. EBF3 introduces metal wire into a molten pool created on the surface of a substrate by a focused electron beam. Part geometry is achieved by translating the substrate with respect to the beam to build the part one layer at a time. Tensile properties demonstrated for electron beam deposited aluminum and titanium alloys are comparable to wrought products, although the microstructures of the deposits exhibit cast features. Understanding the metallurgical mechanisms controlling mechanical properties is essential to maximizing application of the EBF3 process. Tensile mechanical properties and microstructures were examined for aluminum alloy 2219 fabricated over a range of EBF3 process variables. Unique microstructures were observed within the deposited layers and at interlayer boundaries, which varied within the deposit height due to microstructural evolution associated with the complex thermal history experienced during subsequent layer deposition. Microstructures exhibited irregularly shaped grains with interior dendritic structures, described based on overall grain size, morphology, distribution, and dendrite spacing, and were correlated with deposition parameters. Fracture features were compared with microstructural elements to define fracture paths and aid in definition of basic processing-microstructure-property correlations.

  1. Effects of Mm(NiCoAlMn)5 hydrogen storage alloy coated with Ni-Co-P alloy by electroless plating on electrochemical properties of hydride electrodes

    Institute of Scientific and Technical Information of China (English)

    孙春文; 郭占成; 唐致远; 郭鹤桐

    2003-01-01

    The effect of chemical plating with Ni-Co-P alloy on the properties of MH electrodes is investigated. The results show that the efficiency of storage alloy and the activation of MH electrode have been improved by introducing 1.74% cobalt in the Ni-Co-P alloy coating. The initial discharge capacity is 208 mAh/g. The maximum discharge capacity gets to 298.5 mAh/g. At the same time the cycle life of MH electrodes is improved. The discharge capacity of MH electrodes coated with Ni-Co-P is 88% of the maximum discharge capacity after 300 cycles. Whereas the discharge capacity of bare alloy electrodes retains 62% of the maximum capacity after 300 cycles. An increment of discharge capacity is mainly due to the superposition of the oxidation current of Co as well as improved efficiency of microcurrent collection. The effect of Ni-Co-P alloy coating by electroless plating on the kinetic properties of hydride electrode has been systematically investigated by electrochemical techniques. The results indicate that the kinetic properties of MH electrodes, including exchange current density, limiting current density, have been improved markedly. This improvement of kinetic properties leads to the decrease of the overpotential of anodic and cathodic polarization.

  2. Enhanced creep properties of copper and its alloys processed by ECAP

    Science.gov (United States)

    Dvorak, J.; Kral, P.; Svoboda, M.; Kvapilova, M.; Sklenicka, V.

    2014-08-01

    This work describes the effect of equal channel angular pressing (ECAP) on the microstructure and creep properties of pure copper and its two binary alloys with addition of small amounts of Zr or Co. The ECAP pressing was performed at room temperature by route Bc up to 12 passes using a die with an internal angle of 90° between the two parts of the channel. Ultrafine-grained (UFG) microstructure formed through ECAP process has been studied by methods of transmission electron microscopy (TEM) and scanning electron microscopy (SEM) equipped with the electron backscatter diffraction (EBSD) unit. Tensile creep tests were conducted in tension at temperature 673 K and at different applied stresses on ECAP material and, for comparison purposes, on unpressed coarse-grained states of materials under investigation too. It was found that both alloys processed by ECAP exhibited similar character of creep behaviour. Creep resistance was markedly improved after first two ECAP passes in comparison with creep behaviour of unpressed materials. The minimum creep rate of ECAP material may be up to two orders of magnitude lower than that of unpressed material. However, subsequent ECAP passes lead to a decline of creep life and the difference in the minimum creep rate for the ECAP material and unpressed state consistently decreases with increasing number of ECAP passes. Further, ECAP process led to significant improvements in fracture strain. The link between microstructural processes and creep behaviour of pressed copper and its selected alloys is examined in detail.

  3. Fabrication And Mechanical Properties Of A Nanostructured Complex Aluminum Alloy By Three-Layer Stack Accumulative Roll-Bonding

    Directory of Open Access Journals (Sweden)

    Lee S.-H.

    2015-06-01

    Full Text Available A multi-layered complex aluminum alloy was successfully fabricated by three-layer stack accumulative roll bonding(ARB process. The ARB using AA1050 and AA5052 alloy sheets was performed up to 7 cycles at ambient temperature without lubrication. The specimen processed by the ARB showed a multi-layer aluminum alloy sheet in which two aluminum alloys are alternately stacked. The grain size of the specimen decreased with the number of ARB cycles, became about 350nm in diameter after 7cycles. The tensile strength increased with the number of ARB cycles, after 6c it reached 281MPa which is about twice higher than that of the starting material. The microstructures and mechanical properties of a three-layer AA1050/AA5052 alloy fabricated by the ARB were compared to those of the conventional ARB-processed material.

  4. Study the Magnetic Properties of Invar Alloys by Using High Pressure Mössbaur Spectroscopy

    Directory of Open Access Journals (Sweden)

    N. A. Khalefa

    2015-12-01

    Full Text Available High pressure 57F MÖssbaur spectroscopy measurement ( up to 42 Gpa at room temperature have been carried out for investigation the magnetic properties of Ɣ(f.c.c Fe78Ni22 alloys using diamond anvil cell (DAC technique. The mÖssbaur spectrum at 0 Gpa shows a six line magnetic pattern with broad outer peaks and an average hyperfine field of ~32T characteristic of a disordered alloys. In the pressure rang (2alloys (25-35 at % Ni. Our data indicate a pressure induced invar effect for Fe78Ni22 alloy at ~7-12 Gpa. Above 20 Gpa the hyperfine field break down and the alloy becomes non-magnetic showing only a single line MÖsbauer spectrum.

  5. Microstructure and mechanical properties of Ti6321 alloy welded joint by GTAW

    Energy Technology Data Exchange (ETDEWEB)

    Xiong, Jinhui, E-mail: xiongjinhui@126.com; Li, Shikai; Gao, Fuyang; Zhang, Jianxin

    2015-07-29

    Titanium and its alloys have excellent combination of properties, such as low density, high specific strength and corrosion resistance, and they are extensively used in many industrial fields. This work is aiming at investigation on the microstructure and mechanical properties of Ti–6Al–3Nb–2Zr–1Mo (Ti6321) alloy joints by Gas Tungsten Arc Welding (GTAW) with filler materials. The results indicated that the microstructure of the fusion zone (FZ) is composed of acicular α, massive α, and Widmanstatten α+β. The heat affected zone (HAZ) near FZ consists of coarse and acicular α structures of grain boundary α, Widmanstatten α+β. The heat affected zone (HAZ) near base metal consists of primary α phase and transformed β containing acicular α. Microhardness values for HAZ are higher than that of FZ and base metal, and there are the peak values for the HAZ near the weld metal. The tensile strength of joint is almost equal to that of base metal, and the fracture locations of all the tensile specimens are in base metal, and it is well in accordance with the relationship between the content of strengthening and interstitial elements and microstructure and mechanical properties of welded joints. The tensile fracture morphology of joint presents obviously the characteristic of ductile fracture, which is related to the bigger and deeper dimples distributed on the surface of joint. The HAZ impact toughness is lower than that of the BM and FZ.

  6. Improving the fatigue property of welded joints for AZ31 magnesium alloy by ultrasonic peening treatment

    Institute of Scientific and Technical Information of China (English)

    Zhang Jinwang; Wang Wenxian; Zhang Lan; Mu Wei; Xu Bingshe

    2008-01-01

    The fatigue property of AZ31 magnesium alloy and its TIG welded joints were investigated. The ultrasonic peening treatment (UPT) was used to improve the fatigue property of the TIG welded joints, which was treated at the weld toe by the UPT process. The test results show that the fatigue strength of the base metal of AZ31 magnesium alloys is 57.8 MPa, and those of the fillet joint and the transverse cross joint are respectively 20.0 MPa and 17.2 MPa at 2×106 cycles. The fatigue strengths of two kinds of welded joints treated by the UPT are respectively 30.3 MPa and 24.7 MPa, which have been improved by 51.5% and 43.6%, respectively. The fatigue life of the fillet joint specimens is prolonged by about 2.74 times and the fatigue life of the transverse cross joint specimens is prolonged by about 1.05 times when the stress range is at 40.0 MPa.

  7. Mechanical properties and biocorrosion resistance of the Mg-Gd-Nd-Zn-Zr alloy processed by equal channel angular pressing.

    Science.gov (United States)

    Zhang, Junyi; Kang, Zhixin; Wang, Fen

    2016-11-01

    A Mg-Gd-Nd-Zn-Zr alloy was processed by equal channel angular pressing (ECAP) at 375°C. The grain size of Mg-Gd-Nd-Zn-Zr alloy was refined to ~2.5μm with the spherical precipitates (β1 phase) distributing in the matrix. The mechanical properties of ECAPed alloy were significantly improved as a result of the grain refinement and precipitation strengthening. The corrosion rate of the ECAPed magnesium alloy in simulated body fluid dramatically decreased from 0.236mm/a to 0.126mm/a due to the strong basal texture and refined microstructure. This wrought magnesium alloy shows potentials in biomedical application. PMID:27524012

  8. Mechanical properties and biocorrosion resistance of the Mg-Gd-Nd-Zn-Zr alloy processed by equal channel angular pressing.

    Science.gov (United States)

    Zhang, Junyi; Kang, Zhixin; Wang, Fen

    2016-11-01

    A Mg-Gd-Nd-Zn-Zr alloy was processed by equal channel angular pressing (ECAP) at 375°C. The grain size of Mg-Gd-Nd-Zn-Zr alloy was refined to ~2.5μm with the spherical precipitates (β1 phase) distributing in the matrix. The mechanical properties of ECAPed alloy were significantly improved as a result of the grain refinement and precipitation strengthening. The corrosion rate of the ECAPed magnesium alloy in simulated body fluid dramatically decreased from 0.236mm/a to 0.126mm/a due to the strong basal texture and refined microstructure. This wrought magnesium alloy shows potentials in biomedical application.

  9. Elastic properties of sulphur and selenium doped ternary PbTe alloys by first principles

    Energy Technology Data Exchange (ETDEWEB)

    Bali, Ashoka, E-mail: rcmallik@physics.iisc.ernet.in; Chetty, Raju, E-mail: rcmallik@physics.iisc.ernet.in; Mallik, Ramesh Chandra, E-mail: rcmallik@physics.iisc.ernet.in [Thermoelectric Materials and Devices Laboratory, Department of Physics, Indian Institute of Science, Bangalore-560012 (India)

    2014-04-24

    Lead telluride (PbTe) is an established thermoelectric material which can be alloyed with sulphur and selenium to further enhance the thermoelectric properties. Here, a first principles study of ternary alloys PbS{sub x}Te{sub (1−x)} and PbSe{sub x}Te{sub (1−x)} (0≤x≤1) based on the Virtual Crystal Approximation (VCA) is presented for different ratios of the isoelectronic atoms in each series. Equilibrium lattice parameters and elastic constants have been calculated and compared with the reported data. Anisotropy parameter calculated from the stiffness constants showed a slight improvement in anisotropy of elastic properties of the alloys over undoped PbTe. Furthermore, the alloys satisfied the predicted stability criteria from the elastic constants, showing stable structures, which agreed with the previously reported experimental results.

  10. Microstructure and Mechanical Tensile Properties of a VT6 Alloy Manufactured by Selective Laser Melting

    Science.gov (United States)

    Nazarova, T. I.; Imayev, V. M.; Imayev, R. M.; Pavlinich, S. P.

    2015-10-01

    The microstructure and tensile properties of a material manufactured from the VT6 titanium alloy by the method of selective laser melting (SLM) are investigated. In the initial state, the microstructure of the SLMmaterial consists of columnar β-grains elongated in the direction of heat sink, which were transformed during cooling into the acicular martensite α'-phase. A heat treatment, including two-stage annealing at 900 and 700°C, transfers the microstructure into equilibrium, two-phase state, with the elongation of β-grains being retained. Mechanical tensile tests were performed in the direction normal to the layer packing formed during SLM. It is found that strength properties of the workpiece manufactured by the SLM process are similar to those of the VT6 alloy manufactured by conventional casting, while its room-temperature ductility is noticeably higher. Deformation-relief studies of the specimen surface demonstrated that the layers formed during SLM affect neither the development of deformation nor fracture of the material.

  11. Investigation into thermodynamic properties of indium-copper system alloys by method of instant emf registration

    International Nuclear Information System (INIS)

    Direct measurement of activity of In-Cu alloy both components is carried out. Thermodynamic properties of (In0.147Cu0.853; In0.326Cu0.674; In0.341Cu0.659; In0.302Cu0.638; In0.617Cu0.383) alloys calculated proceeding from the measured activities, well agree with each other and the literary data. 6 refs.; 3 tabs

  12. Influence of substructure on mechanical properties of austenitic alloys deformed by warm rolling

    Energy Technology Data Exchange (ETDEWEB)

    Izotov, V.I.; Virakhovskij, Yu.G.; Marusenko, S.Ya. (Tsentral' nyj Nauchno-Issledovatel' skij Inst. Chernoj Metallurgii, Moscow (USSR). Inst. Metallovedeniya i Fiziki Metallov)

    1983-08-01

    A connection between a substructure and mechanical properties of some iron base austenitic alloys, differing in carbon, and carbide-forming element contents and in stacking fault energies after warm rolling, is studied. It is shown that the maximum value of yield strength after cold hardening is achieved in the alloy with low stacking fault energy due to the formation of high density of thin twins.

  13. Influence of substructure on mechanical properties of austenitic alloys deformed by warm rolling

    International Nuclear Information System (INIS)

    A connection between a substructure and mechanical properties of some iron base austenitic alloys, differing in carbon, and carbide-forming element contents and in stacking fault energies after warm rolling, is studied. It is shown that the maximum value of yield strength after cold hardening is achieved in the alloy with low stacking fault energy due to the formation of high density of thin twins

  14. MICROSTRUCTURE ANALYSIS AND MECHANICAL PROPERTIES OF Zn-Al ALLOY ROD PRODUCED BY HEATED MOLD CONTINUOUS CASTING

    Institute of Scientific and Technical Information of China (English)

    Y. Ma; Y. Hao; F.Y. Yan; H.J.Liu

    2003-01-01

    The new technology of continuous casting by heated mold was used to produce dtirectional solidification ZA alloy lines to eliminate the inter defects of these lines and increase their mechanical properties. The results are as follows: (1) The microstructure of the ZA alloy lines is the parallel directional dendritic columnar crystal. Every dendritic crystal of eutectic alloy ZA5 was composed of many layer eutectic β and η phases. The microstructure of hypereutectic ZA alloys is primary dendritic crystal and interdendritic eutectic structure. The primary phase of ZA8 and ZA12 isβ,among them, but the primary phase of ZA22 and ZA27 is α. (2) Through the test to the as-cast ZA alloy lines made in continuous casting by heated mold, it is found that the tensile strength and hardness increase greatly, but the elongation decreases. With the increase of aluminum amount from ZA 5 to ZA 12, ZA22 and ZA27, the tensile strength increases gradually. ZA27 has the best comprehensive mechanical properties in these four kinds of ZA alloys. (3) Heat treatment can decrease the dendritic segregation and improve the elongation of ZA alloy, but make their strength decrease slightly.

  15. Influence of yttrium on microstructure and properties of Ni–Al alloy coatings prepared by laser cladding

    OpenAIRE

    Cun-shan Wang

    2014-01-01

    Ni–Al alloy coatings with different Y additions are prepared on 45# medium steel by laser cladding. The influence of Y contents on the microstructure and properties of Ni–Al alloy coatings is investigated using X-ray diffraction, scanning electron microscopy, electron probe microanalyzer, Vickers hardness tester, friction wear testing machine, and thermal analyzer. The results show that the cladding layers are mainly composed of NiAl dendrites, and the dendrites are gradually refined with the...

  16. [Research on the mechanical properties of bone scaffold reinforced by magnesium alloy/bioceramics composite with stereolithography double channels].

    Science.gov (United States)

    Li, Changhai; Lian, Qin; Zhuang, Pei; Wang, Junzhong; Li, Dichen

    2015-02-01

    Focusing on the poor mechanical strength of porous bioceramics bone scaffold, and taking into account of the good mechanical properties of biodegradable magnesium alloy, we proposed a novel method to fabricate magnesium alloy/bioceramics composite bone scaffold with stereolithography double channels. Firstly, a scaffold structure without mutually connected double channels was designed. Then, an optimized bioceramics scaffold was fabricated according to stereolithography and gel-casing. Molten AZ31 magnesium alloy was perfused into the secondary channel of scaffold by low-pressure casting, and magnesium alloy/bioceramics composite bone scaffold was obtained when magnesium alloy was solidified. The compression test showed that the strength of bioceramics scaffold with only one channel and without magnesium alloy was (9.76 ± 0.64) MPa, while the strength of magnesium alloy/bioceramics composite scaffold with double channels was (17.25 ± 0.88) MPa. It can be concluded that the magnesium alloy/bioceramics composite is obviously able to improve the scaffold strength.

  17. Preliminary Study on Some Properties of Co-Cr Dental Alloy Formed by Selective Laser Melting Technique

    Institute of Scientific and Technical Information of China (English)

    ZHANG Biao; HUANG Qirong; GAO Yang; LUO Peng; ZHAO Chuang

    2012-01-01

    The surface condition,some properties and ion releasing behavior of cobalt-chromium (Co-Cr)dental alloy formed by selective laser melting (SLM) technique were investigated.Before porcelain fused firing,the surface condition of the Co-Cr alloy was observed using a scanning electron microscope (SEM),and then the density and hardness were examined.After porcelain fused firing,the interface of porcelain and alloy was observed,and then the metal-ion release of the samples was tested.SLM technique provides Co-Cr alloy higher hardness than casting method.After degassing-oxidation procedure and porcelain fused firing,the interface of the alloy and porcelain showed excellent combination.Co ion was more than Cr ion released from SLM Co-Cr alloy,the amounts of Co and Cr ions were safe according to ISO security criterion.Considering the properties before and after porcelain fused sintering process,SLM technique is suitable for dental Co-Cr alloy restoration.

  18. Microstructural evolution and mechanical properties of the Ti–6Al–4V alloy produced by vacuum hot-pressing

    International Nuclear Information System (INIS)

    Highlights: ► Hot-pressing is used to make almost fully dense Ti–6Al–4V alloy components. ► Study of the bending properties of the Ti–6Al–4V alloy processed by vacuum hot-pressing. ► Study of the interaction between Ti–6Al–4V and the BN coating. ► Microstructural evolution of prealloyed and master alloy materials with the temperature. - Abstract: In this work, the properties of the titanium industry workhorse, the Ti–6Al–4V alloy, processed by vacuum hot-pressing are studied. More in detail, relative density, microstructure characterisation and chemical analysis, precisely oxygen, nitrogen and carbon content, as well as flexural properties and hardness are considered. Components with relative density as high as 98% and mechanical properties similar to the wrought alloy, where these properties are affected by the formation of a reacted layer due to the interaction between titanium and the boron nitride (BN) coating, are obtained.

  19. New Dental Alloys with Special Consumer Properties

    Institute of Scientific and Technical Information of China (English)

    TYKOCHINSKIY D. S.; VASEKIN V. V.

    2012-01-01

    The purpose of the investigation was to create a new gold alloy of yellow for casting the frames of metal-ceramic dentures.The yellow color corresponds to the consumer and aesthetic needs of some patients,because it is a sign of the metal,which is noble and innocuous.The main alloying elements of the majority of gold alloys for metal-ceramics are platinum and palladium,which increase the strength characteristics.Copper,tin,and other precious metals and base metals are also introduced in these alloys.At the same time,it is necessary to ensure the correspondence of the properties of the alloy with those of the ceramics applied onto the metal frame.For this purpose,the thermal expansion coefficient of the alloy (TEC) should be in a range of 13.5~14.5 × 10-6 K-1 when heated from 20 to 600 ℃.The two-component alloys,alloying of gold with platinum and palladium results in a decrease in the TEC,and the introduction of copper,silver,and tin,increases it.Multidirectional influence of the alloying elements is a factor in achieving compliance of the TEC with the given values of the alloy.In multicomponent systems,however,the mutual influence of individual components on the properties of the alloy is unpredictable.This also applies to the color characteristics of the alloys,which vary in the direction of reducing the yellowness with increasing concentration of platinum and palladium,while other elements may have the opposite effect on the results.Yellowness index (YI),calculated according to the results of spectrophotometric studies,has been chosen as an objective indicator of color.In this study,the requirement for YI was given not less than 25; the color of such alloys can be called light yellow.All the alloys investigated contained 85% (by weight)of gold.Therefore,higher corrosion resistance and biological inertness of a finished dental products were ensured.Among the alloys that met the yellowness/TEC requirements,two alloys have been selected that were "most yellow

  20. Wear and Corrosion Properties of Mo Surface-modiifed Layer in TiNi Alloy Prepared by Plasma Surface Alloying

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hongqian; WANG Zhenxia; YANG Hongyu; SHAN Xiaolin; LIU Xiaoping; YU Shengwang; HE Zhiyong

    2016-01-01

    In order to improve the wear resistance and restrain nickel release of TiNi alloys, the Mo modified layers on TiNi substrates were obtained using the double glow plasma surface alloying technique. Scanning electron microscopy (SEM), glow discharge optical emission spectroscopy (GDOES) and X-ray diffraction (XRD) were employed to investigate the morphology, composition and structure. Microhardness test and scratch test were performed to analyze the microhardness and coating/substrate adhesion. Tribological and electrochemical behaviors of the Mo modified layers on TiNi were tested by the reciprocating wear instrument and electrochemical measurement system. The Ni concentrations in Hanks’ solution where surface electrochemical tests took place were measured by mass spectrometry. The surface-modiifed layer contained a Mo deposition layer and a Mo diffusion layer. The X-ray diffraction analysis revealed that the modiifed layers were composed of Mo, MoTi, MoNi, and Ti2Ni. The microhardnesses of the Mo modiifed layers treated at 900℃and 950℃ were 832.8 HV and 762.4 HV, respectively, which was about 3 times the microhardness of the TiNi substrate. Scratch tests indicated that the modified layers possessed good adhesion with the substrate. Compared with as-received TiNi alloy, the modiifed alloys exhibited signiifcant improvement of wear resistance against Si3N4 with low normal loads during the sliding tests. Mass spectrometry displayed that the Mo alloy layers had successfully inhibited the Ni release into the body.

  1. Stress-Corrosion Cracking Property of Aluminum-Magnesium Alloy Processed by Equal-Channel Angular Pressing

    Directory of Open Access Journals (Sweden)

    Hiroaki Nakano

    2012-01-01

    Full Text Available Stress-corrosion cracking property of an aluminum-magnesium alloy processed by equal-channel angular pressing (ECAP was investigated by a slow strain-rate tensile technique in a 3% NaCl solution of pH 4.2 at 303 K. The maximum stress and elongation of the Al-Mg alloy were lower in the NaCl solution than in air. The stress-corrosion cracking property was evaluated by the decrease ratio of maximum stress and elongation of the Al-Mg alloy with NaCl solution, (max and (, respectively. (max and ( were lower with ECAP than without it, showing that the susceptibility of stress-corrosion cracking decreased with ECAP. The polarization curve and time dependence of the anodic current density at constant potential of the Al-Mg alloy in the NaCl solution revealed that the anodic current density was lower with ECAP than without it, or the corrosion resistance of the Al-Mg alloy was improved by ECAP. The decrease in stress-corrosion crack susceptibility of the Al-Mg alloy with ECAP is attributed to an improvement in corrosion resistance afforded by ECAP.

  2. Magnetic and transport properties of Cu{sub 2}MnAl Heusler alloy prepared by rapidly quenched method

    Energy Technology Data Exchange (ETDEWEB)

    Bo Bang [Institute of Materials Science, VAST, 18 Hoang Quoc Viet, Hanoi (Viet Nam); Nguyen Huy Dan [Institute of Materials Science, VAST, 18 Hoang Quoc Viet, Hanoi (Viet Nam)]. E-mail: dannh@ims.vast.ac.vn; Nguyen Anh Tuan [Institute of Materials Science, VAST, 18 Hoang Quoc Viet, Hanoi (Viet Nam); Nguyen Xuan Phuc [Institute of Materials Science, VAST, 18 Hoang Quoc Viet, Hanoi (Viet Nam)

    2007-03-15

    The Cu{sub 2}MnAl alloy was prepared by rapidly quenched (suction-casting and melt-spinning) methods with various thicknesses of 20, 40 and 1000 {mu}m. The X-ray diffraction (XRD) patterns of the fabricated samples show a single phase of Cu{sub 2}MnAl. All the samples reveal soft magnetic behavior with coercivity below 1.6 kA/m and Curie temperature of about 600 K. Resistance of the alloy behaves as a linear function of applied magnetic field. Magnetoresistance (MR) ratio depends on the thickness of the samples and achieves {approx}0.8% at the field of 240 kA/m for the sample with thickness of 20 {mu}m. The variation of the properties of the alloy can be interpreted by the difference of energy band structure caused by defects in the alloy.

  3. Effects of alloying elements on elastic properties of Al by first-principles calculations

    Directory of Open Access Journals (Sweden)

    Wang J.

    2014-01-01

    Full Text Available The effects of alloying elements (Co, Cu, Fe, Ge, Hf, Mg, Mn, Ni, Si, Sr, Ti, V, Y, Zn, and Zr on elastic properties of Al have been investigated using first-principles calculations within the generalized gradient approximation. A supercell consisting of 31 Al atoms and one solute atom is used. A good agreement is obtained between calculated and available experimental data. Lattice parameters of the studied Al alloys are found to be depended on atomic radii of solute atoms. The elastic properties of polycrystalline aggregates including bulk modulus (B, shear modulus (G, Young’s modulus (E, and the B/G ratio are also determined based on the calculated elastic constants (cij’s. It is found that the bulk modulus of Al alloys decreases with increasing volume due to the addition of alloying elements and the bulk modulus is also related to the total molar volume (Vm and electron density (nAl31x with the relationship of nAl31x=1.0594+0.0207√B/Vm. These results are of relevance to tailor the properties of Al alloys.

  4. Electromagnetic properties of flake-shaped Fe–Si alloy particles prepared by ball milling

    International Nuclear Information System (INIS)

    Flake-shaped Fe–Si alloy particles with high aspect ratios were fabricated by ball milling commercially available Fe–Si powder, aiming to fabricate high-performance microwave absorbing fillers for coatings applied in 1–4 GHz range. To compare with spherical particles, higher permittivity and permeability was observed by using flaky particles as fillers. High aspect ratios contributed to an enhanced dielectric relaxation in the 1–4 GHz band, resulting in an increased permittivity. The thin thickness together with the high resistivity of Fe–Si flakes was believed to be helpful for suppressing the effect of eddy current and thus lead to an increase in the permeability. The electromagnetic wave absorbing (EMA) performances were observed to be enhanced. With a thin thickness of 2 mm, a wide absorption band with a minimum reflection loss of −12 dB was achieved in 1–4 GHz range, when using 75 wt% of flaky Fe–Si particles as fillers. The study indicated that flake-shaped Fe–Si particles were a promising candidate for EMA materials in L and S bands. - Highlights: • Flaky Fe–Si alloy particles were prepared in large scale via a simple ball milling method. • Coatings containing flakes Fe–Si particles present excellent EMA performance in L–S band. • The high shape anisotropy and the thin thickness contribute to the excellent EM property

  5. High Strength AA7050 Al alloy processed by ECAP: Microstructure and mechanical properties

    International Nuclear Information System (INIS)

    Highlights: → ECAP improves the strength of the AA7050 Al alloy with no loss on ductility. → Room temperature ECAP strengthens the alloy by grain refinement and work hardening. → ECAP at 150 deg. C strengthens the alloy by grain refinement and precipitation. → Second phase precipitation is accelerated by ECAP. → Precipitates morphology is modified by ECAP. - Abstract: Commercial AA7050 aluminium alloy in the solution heat-treated condition was processed by ECAP through routes A and BC. Samples were processed in both room temperature and 150 deg. C, with 1, 3, and 6 passes. The resulting microstructure was evaluated by optical microscopy (OM) and transmission electron microscopy (TEM). Only one pass was possible at room temperature due to the low ductility of the alloy under this condition. In all cases, the microstructure was refined by the formation of deformation bands, with dislocation cells and subgrains inside these bands. The increase of the ECAP temperature led to the formation of more defined subgrain boundaries and intense precipitation of spherical-like particles, identified as η' and η phases. After the first pass, an increase in the hardness was observed, when compared with the initial condition. After 3 passes the hardness reached a maximum value, higher than the values typically observed for this alloy in the overaged condition. The samples processed by route BC evolved to a more refined microstructure. ECAP also resulted in significant strength improvement, compared to the alloy in the commercial overaged condition.

  6. Tribological Properties of the Fe-Al-Cr Alloyed Layer by Double Glow Plasma Surface Metallurgy

    Science.gov (United States)

    Luo, Xixi; Yao, Zhengjun; Zhang, Pingze; Zhou, Keyin; Wang, Zhangzhong

    2016-09-01

    A Fe-Al-Cr alloyed layer was deposited onto the surface of Q235 low-carbon steel via double glow plasma surface metallurgy (DGPSM) to improve the steel's wear resistance. After the DGPSM treatment, the Fe-Al-Cr alloyed layer grown on the Q235 low-carbon steel was homogeneous and compact and had a thickness of 25 µm. The layer was found to be metallurgically adhered to the substrate. The frictional coefficient and specific wear rate of the sample with a Fe-Al-Cr alloyed layer (treated sample) were both lower than those of the bare substrate (untreated sample) at the measured temperatures (25, 250 and 450 °C). The results indicated that the substrate and the alloyed layer suffered oxidative wear and abrasive wear, respectively, and that the treated samples exhibited much better tribological properties than did the substrate. The formation of Fe2AlCr, Fe3Al(Cr), FeAl(Cr), Fe(Cr) sosoloid and Cr23C6 phases in the alloyed layer dramatically enhanced the wear resistance of the treated sample. In addition, the alloyed layer's oxidation film exhibited a self-healing capacity with lubrication action that also contributed to the improvement of the wear resistance at high temperature. In particular, at 450 °C, the specific wear rate of treated sample was 2.524 × 10-4 mm3/N m, which was only 45.2% of the untreated sample.

  7. Properties enhancement of Al-Zn-Mg alloy by retrogression and re-aging heat treatment

    Directory of Open Access Journals (Sweden)

    Zaid H.R.

    2011-01-01

    Full Text Available The higher strength 7xxx aluminum alloys exhibited low resistance to stress corrosion cracking (SCC when aged to the peak hardness (T6 temper. The overaged alloys (T7 temper developed to enhance the SCC with loss in the strength of the alloy. Recently, retrogression and re-aging (RRA heat treatments are used for improving the SCC behavior for alloys in T6 tempers such as 7075, 7475 and 8090. In this study, an application of retrogression and re-aging heat treatment processes are carried out to enhance toughness properties of the 7079-T651 aluminum alloy, while maintaining the higher strength of T651-temper. The results of charpy impact energy and electrical conductivity tests show a significantly increases in absorbed energy and electrical conductivity values, when the alloys are exposed to various retrogression temperatures (190, 200, 210°C and times (20, 40, 60 minutes, and then re-aged at 160°C for 18 hours.

  8. Improvement of Creep and High Temperature Tensile Properties by Adding W to Orthorhombic Ti2AlNb-Based Alloys

    Institute of Scientific and Technical Information of China (English)

    Fang Tang; Satoshi Emura; Masuo Hagiwara

    2000-01-01

    The Orthorhombic Ti2AlNb-based alloys (O alloys) are potential high temperature materials for applications in aircraft engines for their high specific strength. In this paper, with the purpose of enhancing the mechanical properties, W is added to O alloys as the quarternary alloying element. The effects of W additive on the high temperature tensile properties and creep resistance are investigated. The effects of boron doping on these properties are also studied.

  9. Microstructure And Mechanical Properties Of An Al-Zn-Mg-Cu Alloy Produced By Gravity Casting Process

    Directory of Open Access Journals (Sweden)

    Saikawa S.

    2015-06-01

    Full Text Available High-strength aluminum alloy are widely used for structural components in aerospace, transportation and racing car applications. The objective of this study is to enhance the strength of the Al-Zn-Mg-Cu alloy used for gravity casting process. All alloys cast into stepped-form sand mold (Sand-mold Casting; SC and Y-block shaped metal mold(Permanent mold Casting; PC C and then two –step aged at 398-423 K after solution treated at 743 K for 36 ks. The tensile strength and total elongation of the two-step aged SC alloys were 353-387 MPa and about 0.4% respectively. This low tensile properties of the SC alloys might be caused by remaining of undissolved crystallized phase such as Al2CuM, MgZn2 and Al-Fe-Cu system compounds. However, good tensile properties were obtained from PC alloys, tensile strength and 0.2% proof stress and elongation were 503-537 MPa, 474-519 MPa and 1.3-3.3%.

  10. Hard recharging. Metallurgical characteristics and use properties of hard recharging deposited by based cobalt alloys melting

    International Nuclear Information System (INIS)

    Hard recharging with cobalt base alloys are used in different parts of nuclear power plants. This paper presents mechanical properties, wear, thermal shock and corrosion resistances of hard coatings according to RCC-M S8000 rules, and explains relations between code recommendations and uses characteristics. (A.B.). 9 figs., 4 tabs

  11. Influence of shot peening on corrosion properties of biocompatible magnesium alloy AZ31 coated by dicalcium phosphate dihydrate (DCPD).

    Science.gov (United States)

    Mhaede, Mansour; Pastorek, Filip; Hadzima, Branislav

    2014-06-01

    Magnesium alloys are promising materials for biomedical applications because of many outstanding properties like biodegradation, bioactivity and their specific density and Young's modulus are closer to bone than the commonly used metallic implant materials. Unfortunately their fatigue properties and low corrosion resistance negatively influenced their application possibilities in the field of biomedicine. These problems could be diminished through appropriate surface treatments. This study evaluates the influence of a surface pre-treatment by shot peening and shot peening+coating on the corrosion properties of magnesium alloy AZ31. The dicalcium phosphate dihydrate coating (DCPD) was electrochemically deposited in a solution containing 0.1M Ca(NO3)2, 0.06M NH4H2PO4 and 10mL/L of H2O2. The effect of shot peening on the surface properties of magnesium alloy was evaluated by microhardness and surface roughness measurements. The influence of the shot peening and dicalcium phosphate dihydrate layer on the electrochemical characteristics of AZ31 magnesium alloy was evaluated by potentiodynamic measurements and electrochemical impedance spectroscopy in 0.9% NaCl solution at a temperature of 22±1°C. The obtained results were analyzed by the Tafel-extrapolation method and equivalent circuit method. The results showed that the application of shot peening process followed by DCPD coating improves the properties of the AZ31 surface from corrosion and mechanical point of view. PMID:24863232

  12. Surface properties of low alloy steel treated by plasma nitrocarburizing prior to laser quenching process

    Science.gov (United States)

    Wang, Y. X.; Yan, M. F.; Li, B.; Guo, L. X.; Zhang, C. S.; Zhang, Y. X.; Bai, B.; Chen, L.; Long, Z.; Li, R. W.

    2015-04-01

    Laser quenching (LQ) technique is used as a part of duplex treatments to improve the thickness and hardness of the surface layers of steels. The present study is to investigate the surface properties of low alloy steel treated by plasma nitrocarburizing (PNC) prior to a laser quenching process (PNC+LQ). The microstructure and properties of PNC+LQ layer determined are compared with those obtained by PNC and LQ processes. OM, XRD, SEM and EDS analyses are utilized for microstructure observation, phases identification, morphology observation and chemical composition detection, respectively. Microhardness tester and pin-on-disc tribometer are used to investigate the mechanical properties of the modified layers. Laser quenching of plasma nitrocarburized (PNC+LQ) steel results in much improved thickness and hardness of the modified layer in comparison with the PNC or LQ treated specimens. The mechanism is that the introduction of trace of nitrogen decreases the eutectoid point, that is, the transformation hardened region is enlarged under the same temperature distribution. Moreover, the layer treated by PNC+LQ process exhibits enhanced wear resistance, due to the lubrication effect and optimized impact toughness, which is contributed to the formation of oxide film consisting of low nitrogen compound (FeN0.076) and iron oxidation (mainly of Fe3O4).

  13. Achieving superplastic properties in a ZK10 magnesium alloy processed by equal-channel angular pressing

    OpenAIRE

    Figueiredo, Roberto B.; Terence G. Langdon

    2016-01-01

    Equal-channel angular pressing provides an opportunity for refining the grain structure and introducing superplastic properties in magnesium alloys. This report describes the use of this processing technique with a ZK10 (Mg–1.0 wt.% Zn–0.26 wt.% Zr) alloy. The grain structure was successfully refined from ~12.9um to ~5.2um after 4 passes and superplastic elongations were observed when testing at low strain rates at temperatures of 473 and 523 K. An analysis shows that the superplastic behavio...

  14. Microstructure and magnetic properties of nanostructured (Fe0.8Al0.2)100–xSix alloy produced by mechanical alloying

    International Nuclear Information System (INIS)

    We report on how the microstructure and the silicon content of nanocrystalline ternary (Fe0.8Al0.2)100–xSix powders (x=0, 5, 10, 15 and 20 at%) elaborated by high energy ball milling affect the magnetic properties of these alloys. The formation of a single-phase alloy with body centred cubic (bcc) crystal structure is completed after 72 h of milling time for all the compositions. This bcc phase is in fact a disordered Fe(Al,Si) solid solution with a lattice parameter that reduces its value almost linearly as the Si content is increased, from about 2.9 Å in the binary Fe80Al20 alloy to 2.85 Å in the powder with x=20. The average nanocrystalline grain size also decreases linearly down to 10 nm for x=20, being roughly half of the value for the binary alloy, while the microstrain is somewhat enlarged. Mössbauer spectra show a sextet thus suggesting that the disordered Fe(Al,Si) solid solution is ferromagnetic at room temperature. However, the average hyperfine field diminishes from 27 T (x=0) to 16 T (x=20), and a paramagnetic doublet is observed for the powders with higher Si content. These results together with the evolution of both the saturation magnetization and the coercive field are discussed in terms of intrinsic and extrinsic properties. - Highlights: • Single-phase nanocrystalline (Fe0.8Al0.2)100–xSix (x=0, 5, 10, 15 and 20 at%) powders were successfully fabricated by mechanical alloying for a milling time of 72 h. • The insertion of Si atoms leads to a unit-cell contraction and a decrease in the average crystallite size. • The hyperfine and magnetic properties of (Fe0.8Al0.2)100–xSix were influenced by the Si content

  15. Microstructure and Magnetic Properties of Fe-Ni Alloy Fabricated by Selective Laser Melting Fe/Ni Mixed Powders

    Institute of Scientific and Technical Information of China (English)

    Baicheng Zhang; Nour-Eddine Fenineche; Hanlin Liao; Christian Coddet

    2013-01-01

    Fe-Ni alloy,as a widely applied ferromagnetic material,is synthesized using selective laser melting (SLM).The chemical compositions and microstructure of the SLM Fe-Ni alloy are characterized by X-ray diffraction (XRD),energy dispersive X-ray spectroscopy and scanning electron microscopy.It was found that the samples exhibited fine grains with homogenous distribution when a low laser scanning velocity was used.Moreover,the magnetic properties of the samples with different laser parameters are also measured.It shows that the SLM Fe-30%Ni alloy possesses a low coercivity and high saturation magnetization.It also can be obtained that SLM is an alternative faster method to prepare soft magnetic material with complex shapes.Moreover,the magnetic properties can be influenced by the laser parameters.

  16. Abnormal mechanical property evolution induced by heat treatment for a semi-solid forming hypereutectic Al-Fe base alloy

    Directory of Open Access Journals (Sweden)

    Run-xia Li

    2015-05-01

    Full Text Available In the present study, Al-5.5Fe-4Cu-2Zn-0.4Mg-0.5Mn alloy samples were prepared by electromagnetic stirring and semi-solid forming processing, and then the effects of T6 and T1 heat treatments on the microstructures and mechanical properties of the semi-solid forming samples were investigated. The results indicate that after semi-solid forming, the mechanical properties of the sample improved significantly compared to that of the merely electromagnetically stirred sample. The grains of semi-solid forming alloy became almost fine equiaxed; big long strip-shaped Al3Fe phases became short rod-like morphology and distributed uniformly in the matrix. However, the mechanical properties of the T6-treated semi-solid forming sample decreased significantly instead of increasing and, with solution temperature rising, the tensile strength of the alloy decreased further. The results of EDS show that after high temperature solid-solution treatment, the Cu element in the semi-solid forming alloy sample is mainly concentrated at the boundaries of the Al3Fe phases instead of being dissolved in the matrix. At the same time, the grains of the semi-solid forming sample grew slightly after solid-solution treatment. Therefore, the growth of the grains and the accumulation of Cu element at Al3Fe phase boundaries during solution treatment of the semi-solid forming alloy were the main reasons for the mechanical properties decreasing after T6 treatment. The mechanical properties of the alloy were improved after T1 heat treatment due to aging strengthening phase being precipitated in the matrix.

  17. Mechanical properties and machining of aluminum-silicon alloys modified by bismuth or tin

    Science.gov (United States)

    Chen, Peisheng

    The dry machining performance, microstructure and mechanical properties of hypoeutectic and hypereutectic Al-Si alloys modified with different amounts of Bi and Sn, and cast at different cooling rates, were studied. The measured cutting and thrust forces decreased with the addition of Bi and Sn. These elements caused intense shear localization, and promoted the formation of segmented chips, thereby improving the dry machining performance. Also Bi and Sn melted and thus acted as lubricants during dry turning. However, the mechanical properties decreased with the addition of Sn, although Sn had no effect on the Si morphology. Bi had no effect on the Si morphology when cast at high cooling rates. The optimum amount of Bi addition was found to be 0.5 % and this alloy cast under a high cooling rates of 26 °C/s, improved the overall machining performance without compromising the mechanical properties.

  18. Effect of milling on the magnetic properties of Al-Mn obtained by mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Betancourt, Mirna, E-mail: betamirna@gmail.com [Instituto Universitario de Tecnologia Cumana (Venezuela, Bolivarian Republic of); Instituto Venezolano de Investigaciones Cientificas, Lab. Materiales, Centro Ingenieria de Materiales y Nanotecnologia (Venezuela, Bolivarian Republic of); Silva, Pedro [Instituto Venezolano de Investigaciones Cientificas, Lab. Materia Condensada, Centro de Fisica (Venezuela, Bolivarian Republic of); Gonzalez, Gema, E-mail: gemagonz@ivic.gob.ve [Instituto Venezolano de Investigaciones Cientificas, Lab. Materiales, Centro Ingenieria de Materiales y Nanotecnologia (Venezuela, Bolivarian Republic of)

    2012-09-25

    Highlights: Black-Right-Pointing-Pointer Al-42 at.% Mn transforms to {alpha}-Mn(Al) by mechanical milling after 5 h of milling. Black-Right-Pointing-Pointer Transformation to nano {beta}-Mn is reached after 50 h of milling with 6 nm grain size. Black-Right-Pointing-Pointer Milling strongly affects magnetic behavior. - Abstract: Al-Mn powders were prepared to obtain the compound Mn{sub 42}Al{sub 58} by mechanical alloying. The powders were milled during different periods (1 h, 5 h, 11.5 h, 15 h, 20 h and 50 h) using a SPEX 8000 mixer mill in nitrogen atmosphere. The materials were characterized by X-ray diffraction (XRD) and magnetic properties at room temperature, using a vibrating sample magnetometer (VSM). XRD shows partial transformation to {alpha}-Mn after only 1 h of milling and a mixture of {alpha}-Mn and {beta}-Mn after 11.5 h of milling and further milling resulted in transformation to {beta}-Mn phase with a grain size of 6 nm after 50 h. The change in magnetic properties with milling time is quite dramatic, from a ferromagnetic behavior for {alpha}-Mn(Al) to paramagnetic after 11.5 h of milling and showing again ferromagnetic behavior, with a strong increase of magnetization values of 5.5 emu/g, after 50 h of milling with formation of {beta}-Mn(Al).

  19. Antibacterial Property of Cu Modified Stainless Steel by Plasma Surface Alloying

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xiang-yu; HUANG Xiao-bo; JIANG Li; MA Yong; FAN Ai-lan; TANG Bin

    2012-01-01

    Stainless steel(SS) is not recommended to be used in hospital environments for work surfaces and door furniture due to the lack of antibacterial properties.To this end,a novel SS surface modified layer with both a quick bacterial killing rate and relatively thick has been obtained by plasma surface alloying with Cu.The microstructure,elements distribution and phase identification were analyzed by SEM,GDS,XRD and XPS.A spread plate method was adopted for evaluation of antibacterial property of specimens against Escherichia coli(E.coli) and Staphylococcus aureus(S.aureus).The experimental results demonstrate that the surface modified layer with the thickness of about 26 μm is uniform and dense.The layer is mainly composed of a mixture of pure Cu,expanded austenite phase and a few Fe3O4 phase.The Cu modified layer exhibits excellent antibacterial effects against E.coli and S.aureus within 1 h.No viable E.coli and S.aureus was found after 3 h(100% killed).The modified layer is relatively thick,hence it is expected that the Cu modified SS will have a durable antibacterial function

  20. Microstructure and mechanical properties of NiCoCrAlYTa alloy processed by press and sintering route

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, J.C., E-mail: jpereira@uc.edu.ve [Instituto de Tecnología de Materiales, Universidad Politécnica de Valencia, Camino de vera s/n, Valencia, España (Spain); Centro de Investigaciones en Mecánica, Facultad de Ingeniería, Universidad de Carabobo (Venezuela, Bolivarian Republic of); Zambrano, J.C. [Centro de Investigaciones en Mecánica, Facultad de Ingeniería, Universidad de Carabobo (Venezuela, Bolivarian Republic of); Afonso, C.R.M. [Departamento de Engenharia de Materiais, Universidade Federal de São Carlos (UFSCar), São Carlos, SP (Brazil); Amigó, V. [Instituto de Tecnología de Materiales, Universidad Politécnica de Valencia, Camino de vera s/n, Valencia, España (Spain)

    2015-03-15

    poor solid-state diffusion. - Graphical abstract: Display Omitted - Highlights: • We made NiCoCrAlYTa alloy by a conventional powder metallurgy route. • High densification and adequate strength were observed. • The presence of unexpected carbides found along γ/γ and γ/β grain boundaries was detected. • The effect of cold press and sintering processing parameters on the microstructure and mechanical properties were studied.

  1. Microstructure and mechanical properties of NiCoCrAlYTa alloy processed by press and sintering route

    International Nuclear Information System (INIS)

    poor solid-state diffusion. - Graphical abstract: Display Omitted - Highlights: • We made NiCoCrAlYTa alloy by a conventional powder metallurgy route. • High densification and adequate strength were observed. • The presence of unexpected carbides found along γ/γ and γ/β grain boundaries was detected. • The effect of cold press and sintering processing parameters on the microstructure and mechanical properties were studied

  2. Structure and properties of hotwork tool steel alloyed by WC carbides by a use of high power diode laser

    OpenAIRE

    M. Bonek; L.A. Dobrzański; Klimpel, A

    2007-01-01

    Purpose: The paper presents the effect of alloying with tungsten carbide on properties of the X40CrMoV5-1 steel surface layer, using the high power diode laser (HPDL).Design/methodology/approach: The structural mechanism of surface layer development was determined and the effect of alloying parameters, gas protection method, and thickness of paste layer applied onto the steel surface on structure refinement and influence of these factors on the mechanical properties of surface layer was studi...

  3. Mechanical properties and thermal stability of Al–Fe–Ni alloys prepared by centrifugal atomisation and hot extrusion

    Energy Technology Data Exchange (ETDEWEB)

    Průša, F., E-mail: Filip.Prusa@vscht.cz; Vojtěch, D.; Michalcová, A.; Marek, I.

    2014-05-01

    In this work, Al–12Fe and Al–7Fe–5Ni (wt%) alloys prepared by a novel technique including centrifugal atomisation and hot extrusion were studied. The microstructures were investigated using light microscopy, electron scanning microscopy, transmission electron microscopy and X-ray diffraction. The mechanical properties were determined by Vickers hardness measurements and compressive stress–strain tests. To study the thermal stability, the mechanical properties were also measured after 100 h of annealing at 300 °C and 400 °C. In addition, creep tests at a stress of 120 MPa and a temperature of 300 °C were performed. The investigated materials were composed of fine-grained α-Al and intermetallic phases identified as Al{sub 13}Fe{sub 4} and Al{sub 9}FeNi. The Vickers hardness and compressive yield strength were 68 HV5 and 183 MPa, respectively, for the Al–12Fe alloy and 73 HV5 and 226 MPa, respectively, for the Al–7Fe–5Ni alloy. After long-term annealing, the change in the mechanical properties was negligible, indicating the excellent thermal stability of both materials. The creep tests confirmed the highest thermal stability of the Al–7Fe–5Ni alloy with a total compressive creep strain of 15%. The “thermally stable” casting Al–12Si–1Cu–1Mg–1Ni alloy treated by the T6 regime was used as a reference material. The casting alloy exhibited sufficient mechanical properties (hardness and compressive yield strength) at room temperature. However, annealing remarkably softened and reduced its compressive yield strength to almost 50% of the initial values. Additionally, the total creep strain of the casting reference material was almost three times higher than that of the Al–7Fe–5Ni alloy. It has been proven that centrifugally atomised materials quickly compacted via hot extrusion can compete or even exceed the properties of common casting aluminium alloys that are used in automotive industry.

  4. Microstructure and mechanical properties of a Mg–Zn–Y alloy produced by a powder metallurgy route

    Energy Technology Data Exchange (ETDEWEB)

    Asgharzadeh, H. [Department of Materials Engineering, Faculty of Mechanical Engineering, University of Tabriz, P.O. Box 51666-16471, Tabriz (Iran, Islamic Republic of); Department of Materials Science and Engineering, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of); Yoon, E.Y. [Department of Materials Science and Engineering, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of); Chae, H.J.; Kim, T.S. [Korea Institute for Rare Metals, Korea Institute of Industrial Technology, Incheon 406-840 (Korea, Republic of); Lee, J.W. [Korea Institute of Materials Science (KIMS), Changwon 641-831 (Korea, Republic of); Kim, H.S., E-mail: hskim@postech.ac.kr [Department of Materials Science and Engineering, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of)

    2014-02-15

    In this paper, a bulk Mg–Zn–Y alloy reinforced by quasicrystalline particles was produced by hot extrusion of rapidly-solidified powders. MgZn{sub 4.3}Y{sub 0.7} powders with different particle sizes were prepared by an inert gas atomizer and then extruded at 380 °C with extrusion ratios of 10:1, 15:1, and 20:1. Microstructural studies were performed using an optical microscope, scanning electron microscope, transmission electron microscope, and X-ray diffraction. The mechanical strength and hardness of the extruded materials were enhanced by employing finer Mg alloy powders. More uniform deformation of powders in extruded billets with good tensile properties was achieved at higher extrusion ratios, especially for finer powders. The high strength of the MgZn{sub 4.3}Y{sub 0.7} alloy was preserved at elevated temperatures due to the presence of icosahedral phase nanoparticles.

  5. PREDICTION ON THE THERMODYNAMIC PROPERTIES OF TERNARY LIQUID ALLOYS BY MODIFIED COORDINATION EQUATION

    Institute of Scientific and Technical Information of China (English)

    D.P.Tao

    2001-01-01

    The coordination numbers in the Molecular Interaction Volume Model can be calcu-lated from the common physical quantities of pure matters.A significant advantage ofthe model lies in its ability to predict the thermodynamic properties of ternary liqmdalloys using only the binary infinite dilute activity coefficients,and the predicted values are in good agreement with the experimental data of ternary liquid alloys,whichshows that the model is reliable,convenient and economic.

  6. Structural evolution of Cu{sub (1−X)}Y{sub X} alloys prepared by mechanical alloying: Their thermal stability and mechanical properties

    Energy Technology Data Exchange (ETDEWEB)

    Mula, Suhrit, E-mail: smulafmt@iitr.ernet.in [Department of Metallurgical and Materials Engineering, Indian Institute of Technology Roorkee, Roorkee 247667 (India); Setman, Daria [Physics of Nanostructured Materials, University of Vienna, Boltzmanngasse 5, A-1090 Wien (Austria); Youssef, Khaled [Department of Materials Science and Technology, Qatar University, P.O. Box 2713, Doha (Qatar); Scattergood, R.O.; Koch, Carl C [Department of Materials Science and Engineering, NC State University, Raleigh, NC 27695 (United States)

    2015-04-05

    Highlights: • Metastable solid solutions were prepared from Cu–Y nonequilibrium compositions by mechanical alloying. • Gibbs free energy change as per Miedema’s model confirms the formation of metastable alloys. • High Y content alloys showed high thermal stability during extensive annealing at high temperatures. • Stabilized alloys showed very high hardness and improved yield strength. • Mechanisms of high thermal stability and improved mechanical properties were discussed. - Abstract: In the present study, an attempt has been made to synthesize copper based disordered solid solutions by mechanical alloying (MA) of non-equilibrium compositions. The blended compositions of Cu–1% Y, Cu–3% Y, Cu–5% Y and Cu–7.5% Y (at.%) (all the compositions will be addressed as % only hereafter until unless it is mentioned) were ball-milled for 8 h, and then annealed at different temperatures (200–800 °C) for different length of duration (1–5 h) under high purity argon + 2 vol.% H{sub 2} atmosphere. X-ray diffraction (XRD) analysis and Gibbs free energy change calculation confirm the formation of disordered solid solution (up to 7.5%) of Y in Cu after milling at a room temperature for 8 h. The XRD grain size was calculated to be as low as 7 nm for 7.5% Y and 22 nm for 1% Y alloy. The grain size was retained within 35 nm even after annealing for 1 h at 800 °C. Transmission electron microscopy (TEM) analysis substantiates the formation of ultra-fine grained nanostructures after milling. Microhardness value of the as-milled samples was quite high (3.0–4.75 GPa) compared to that of pure Cu. The hardness value increased with increasing annealing temperatures up to 400 °C for the alloys containing 3–7.5% Y, and thereafter it showed a decreasing trend. The increase in the hardness after annealing is attributed to the formation of uniformly distributed ultrafine intermetallic phases in the nanocrystalline grains. The stabilization effect is achieved due to

  7. Microstructure and mechanical properties of NZ30K alloy by semi-continuous direct chill and sand mould casting processes

    Directory of Open Access Journals (Sweden)

    Zheng Xingwei

    2011-02-01

    Full Text Available The Mg-3.0Nd-0.2Zn-0.4Zr (NZ30K alloys were prepared by direct-chill casting (DCC and sand mould casting (SMC processes, respectively and their microstructures and mechanical properties were investigated. The results indicate that casting method plays a remarkable influence on the microstructure and mechanical properties of as-cast NZ30K alloy. The grain size increases from 35-40 μm in the billets made by the DCC to about 100-120 μm in the billets by the SMC. The aggregation of Mg12Nd usually found at the triple joints of grain boundaries in the billets prepared by SMC while is not observable from the billets by DCC. The tensile strengths and elongations of the billets are 195.2 MPa and 15.5% by DCC, and 162.5 MPa and 3.2% by SMC, respectively. The tensile strength of the alloy by DCC is remarkably enhanced by T6 heat treatment, which reached 308.5 MPa. Fracture surfaces of NZ30K alloy have been characterized as intergranular fracture by SMC and quasi-cleavage fracture by DCC, respectively.

  8. Influence of milling time on microstructure and magnetic properties of Fe80P11C9 alloy produced by mechanical alloying

    International Nuclear Information System (INIS)

    Fe80P11C9 alloy with amorphous/nanocrytalline microstructure has been synthesized by mechanical alloying of the elemental powders. The microstructure, thermal behavior and morphology of the produced powders have been studied by X-ray diffraction (XRD), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM), respectively. The crystallite size, lattice strain and fraction of the amorphous phase have been calculated by Rietveld refinement method. The results indicate that the powders microstructure consists of α-Fe(P,C) nanocrystals with an average diameter of 9 nm±1 nm dispersed in the amorphous matrix after 90 h of milling. Moreover, the fraction of amorphous phase initially increases up to 90 h of milling and then decreases after 120 h of milling, as a result of mechanical crystallization and formation of Fe2P phase. The magnetic measurements show that while the saturation magnetization decreases continuously with the milling time, the coercivity exhibits a complicated trend. The correlation between microstructural changes and magnetic properties has been discussed in detail. - Highlights: • Glass formation was investigated in Fe80P11C9 by mechanical alloying. • Structural parameters were calculated by Rietveld refinement method. • Milling first increased and then decreased the fraction of amorphous phase. • Magnetic properties were significantly changed upon milling

  9. Influence of milling time on microstructure and magnetic properties of Fe{sub 80}P{sub 11}C{sub 9} alloy produced by mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Taghvaei, A.H. [Department of Materials Science and Engineering, Shiraz University of Technology, Shiraz (Iran, Islamic Republic of); Ghajari, F., E-mail: fati.ghajari@gmail.com [Department of Materials Science and Engineering, Shiraz University, Shiraz (Iran, Islamic Republic of); Markó, D. [IFW Dresden, Institute for Complex Materials, Helmholtzstr. 20, 01069 Dresden (Germany); Prashanth, K.G. [IFW Dresden, Institute for Complex Materials, Helmholtzstr. 20, 01069 Dresden (Germany); Additive manufacturing Center, Sandvik AB, 81181 Sandviken (Sweden)

    2015-12-01

    Fe{sub 80}P{sub 11}C{sub 9} alloy with amorphous/nanocrytalline microstructure has been synthesized by mechanical alloying of the elemental powders. The microstructure, thermal behavior and morphology of the produced powders have been studied by X-ray diffraction (XRD), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM), respectively. The crystallite size, lattice strain and fraction of the amorphous phase have been calculated by Rietveld refinement method. The results indicate that the powders microstructure consists of α-Fe(P,C) nanocrystals with an average diameter of 9 nm±1 nm dispersed in the amorphous matrix after 90 h of milling. Moreover, the fraction of amorphous phase initially increases up to 90 h of milling and then decreases after 120 h of milling, as a result of mechanical crystallization and formation of Fe{sub 2}P phase. The magnetic measurements show that while the saturation magnetization decreases continuously with the milling time, the coercivity exhibits a complicated trend. The correlation between microstructural changes and magnetic properties has been discussed in detail. - Highlights: • Glass formation was investigated in Fe{sub 80}P{sub 11}C{sub 9} by mechanical alloying. • Structural parameters were calculated by Rietveld refinement method. • Milling first increased and then decreased the fraction of amorphous phase. • Magnetic properties were significantly changed upon milling.

  10. Comparative description of structure and properties of Ti-6Al-4V titanium alloy for biomedical applications produced by two methods: conventional (molding and innovative (injection ones

    Directory of Open Access Journals (Sweden)

    J. Klimas

    2013-12-01

    Full Text Available Purpose: In paper characterized two methods produced titanium alloy: hitherto used in industry – conti-casting and innovative method of obtaining solid amorphous alloy by injection casting. The results of studies comparing the structure and properties of the alloy Ti-6Al-4V produced by both methods. Design/methodology/approach: Test samples were titanium alloy Ti-6Al-4V produced by two methods: conventional and injection. To achieve the objective pursued performed the following tests: microstructure observation was carried out, the analysis of mechanical properties (microhardness and corrosion resistance tests were performed in Ringer’s liquid, which simulates the human body fluids. Findings: Microstructural study allowed to observe that titanium alloy T-6Al-4V produced by conventional method has crystalline ordered structure which is characteristic for materials obtained by drawing, with oriented grains and elongated in the direction of drawing. Same alloy produced by injection casting has amorphous structure with occurrences of the single-crystal seeds, that kind of structure has lack of order and regularity. The microhardness study showed, that titanium alloy Ti-6Al-4V produced by drawing has a hardness of less than twice for the same alloy produced by the injection. The corrosion tests conducted in an environment that simulates human body fluids, revealed showed that the materials made by injection have significantly corrosion potential than alloy obtained by drawing. Originality/value: The paper presents a comparative study of titanium alloy produced by drawing and massive amorphous alloy produced by unconventional method – injection casting. By the results proved that the alloy produced by injection has much better properties than alloy produced by drawing.

  11. Ballistic impact properties of mixed multi-layered amorphous surface alloyed materials fabricated by high-energy electron-beam irradiation

    International Nuclear Information System (INIS)

    The objective of this study is to investigate ballistic impact properties of multi-layered amorphous surface alloyed materials fabricated by high-energy electron-beam irradiation. The mixture of Zr-based amorphous alloy powders and LiF+MgF2 flux powders was deposited on a Ti alloy substrate, and then electron beam was irradiated on this powder mixture to fabricate an one-layered surface alloyed material. On top of this layer, the powder mixture was deposited again and then irradiated with electron beam whose beam current was decreased to fabricate the multi-layered surface alloyed material. In the mixed multi-layered surface alloyed materials fabricated with LM1 alloy powders and LM2 or LM10 alloy powders, the surface region consisted of amorphous phases, together with a small amount of crystalline particles, whereas the center region was complicatedly composed of amorphous phases, crystallized phases, and dendritic β phases. Since the surface region mostly composed of amorphous matrix was quite hard, the alloyed materials sufficiently blocked the travel of a projectile. When cracks formed at the surface region propagated into the center region, the formation of many cracks or debris was accelerated, which could beneficially work for absorbing the ballistic impact energy, thereby leading to the higher ballistic impact properties than the surface alloyed materials fabricated with LM1 or LM2 alloy powders

  12. Phase constitution and magnetic properties of Nd10Fe76B4M10 and Nd10Fe76B2M12 (M=Fe, Ti, V, Cr, Mn, Co and Al) alloys prepared by mechanical alloying

    International Nuclear Information System (INIS)

    Phase constitution and magnetic properties of Nd10Fe76B4M10 and Nd10Fe76B2M12 (M=Fe, Ti, V, Cr, Mn, Co and Al) alloys prepared by mechanical alloying and subsequent annealing have been systematically studied. It is found that the components of phases in the alloys critically depend on the additive transition metals M. In all the alloys, only the addition of Ti give significant enhancement to the permanent-magnetic properties. The increase of the Curie temperature in the Ti-doped alloys with an excessively low B content implies that part of the Ti atoms may occupy crystalline sites other than the Fe sites. In all the M additive alloys, with increasing content of the additive elements, the quantity of 1 : 7 phase increases and that of Nd2Fe14B-type phase decreases

  13. A study of the method of making dental prosthetic appliances by sintered titanium alloys: effect of copper powder content on properties of sintered titanium alloy.

    Science.gov (United States)

    Oda, Y; Nakanishi, K; Sumii, T

    1990-02-01

    The effects of added copper powder to the properties of the sintered titanium alloys were investigated by measuring the compressive strength and densities of the green and sintered compacts, the thermal expansion curves and dimensional changes in the sintered compacts, and the accuracy of the crown-type restorations. The compressive strengths of green compacts ranged from 55 to 75 MPa. The expansion of green compacts increased with increased copper content. The sintered density was lower than the green density. The compressive yield strength of sintered compacts ranged from 260 MPa to 410 MPa. The sintered compacts expanded from 0.35% to 1.03% and the expansion increased with increased copper content. The dimensional accuracy of crown-type restorations showed the same dimensional change tendencies as did the sintered compacts. These results showed that the fit and the strength of sintered titanium alloy restorations could be improved.

  14. Electrochemical hydrogen storage properties of La0.95Mg2.05Ni9 alloy prepared by mechanical alloying

    Institute of Scientific and Technical Information of China (English)

    蒙冕武; 刘心宇; 成钧; 周怀营

    2004-01-01

    The structure, microstructure, thermal stability and hydriding characteristics of amorphous La0.95-Mg2.05 Ni9 have been investigated with differential thermal analysis, X-ray diffraction, scanning electron microscopy and battery test. It is found that the increase in mechanical alloying time leads to enhancement in thermal stabilities of amorphous La0. 95 Mg2.05 Ni9 alloy. The amorphous alloy has good charge/discharge ability at room temperature (430 mA · h · g-1 ), but the discharge capacity decreases seriously during cycling tests due to the crystallization of amorphous and oxidization of magnesium on the particle surface in alkaline aqueous solution.

  15. Mechanical properties of NiAl-Y2O3-based powdered alloys produced by directional recrystallization

    Science.gov (United States)

    Povarova, K. B.; Skachkov, O. A.; Drozdov, A. A.; Morozov, A. E.; Pozharov, S. I.

    2014-03-01

    The mechanical properties of NiAl-Y2O3-based powdered composite alloys (0.5-7.5 vol %), including those with an NiAl intermetallic matrix alloyed with 0.5 wt % Fe and 0.1 wt % La have been studied. Structures with various aspect ratios (AR, the ratio of the grain length to the grain diameter) are formed using deformation and subsequent annealing. A combination of the optimum amount of strengthening phase (2.5 vol % Y2O3) and a quasi-single-crystalline structure with a sharp axial texture with the (100) main orientation and AR ≈ 20-40 provides the maximum short-term strength and life at temperatures up to 1400-1500°C. An NiAl-Y2O3 alloy (2.5 vol %) has the best strength properties among all known nickel superalloys at temperatures higher than 1200°C and can operate under moderate loads at temperatures higher than the working temperatures of nickel superalloys (by 100-400°C) and their melting points. Additional alloying with 10 wt % Co and 2 wt % Nb makes it possible to increase the ultimate tensile strength of an intermetallic NiAl matrix at 1100°C by a factor of 1.3-1.4.

  16. Effects of Nb addition on microstructure and mechanical properties of TiNiNb alloys fabricated by elemental powder sintering

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jing; Wang, Huifeng; Liu, Jue; Ruan, Jianming, E-mail: jianming@csu.edu.cn

    2014-07-15

    Porous TiNi binary and TiNiNb ternary alloys of four compositions (Ti{sub 50}Ni{sub 47.5}Nb{sub 2.5}, Ti{sub 50}Ni{sub 45}Nb{sub 5}, Ti{sub 50}Ni{sub 42.5}Nb{sub 7.5}, and Ti{sub 50}Ni{sub 40}Nb{sub 10}) were fabricated by the elemental powder sintering process. The effects of Nb addition on microstructure and mechanical properties of TiNi(Nb) alloys were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and tensile tests, respectively. With the increase of Nb contents, the TiNi matrix as the main phase is always retained, while the intensity of its diffraction peak gradually became weak with the appearance of β-Nb and TiNb phases. Most Nb particles are well-distributed in the TiNi matrix and (Ti,Nb){sub 2}Ni phase is found in the binding domain between Nb phase and TiNi phase. The tensile strength and elastic modulus of TiNiNb alloys increase with the increase of Nb contents, due to the solid solution strengthening effect of Nb-rich particles, the enlarged sintering neck and the strengthened bond between particles. Consequently, Nb plays a crucial role in adjusting composition and improving microstructure and mechanical properties of TiNiNb alloys.

  17. IMPROVING THE MECHANICAL PROPERTIES OF COPPER ALLOYS BY THERMO-MECHANICAL PROCESSING

    Institute of Scientific and Technical Information of China (English)

    M.C.Somani; L.P.Karjalainen

    2004-01-01

    Systematic physical simulation of thermo-mechanical processing routes has been applied on a Gleeble 1500 simulator to four copper alloys(mass %)Cu-0.57Co-0.32Si,Cu-0.55Cr-0.065P,Cu-0.22Zr-0.035Si and Cu-1.01Ni-0.43Si aimed at clarifying the influences of processing conditions on their final properties,strength and electrical conductivity.Flow curves were determined over wide temperature and strain rate ranges.Hardness was used as a measure of the strength level achieved.High hardness was obtained as using equal amounts(strains 0.5)of cold deformation before and after the precipitation annealing stage.The maximum values achieved for the Cu-Co-Si,Cu-Cr-P,Cu-Zr-Si and Cu-Ni-Si alloys were 190,165,178 and 193 HV5,respectively.A thermo-mechanical schedule involving the hot deformation-ageing-cold deformation stages showed even better results for the Cu-Zr-Si alloy.Consequently,the processing routes were designed based on simulation test results and wires of 5 and 2mm in diameters have been successfully processed in the industrial scale.

  18. Microstructure and properties of liquid-phase sintered tungsten heavy alloys by using ultra-fine tungsten powders

    Institute of Scientific and Technical Information of China (English)

    于洋; 王尔德

    2004-01-01

    The microstructure and properties of liquid-phase sintered 93W-4.9Ni-2.1Fe tungsten heavy alloys using ultra-fine tungsten powders (medium particle size of 700 nm) and original tungsten powders (medium particle size of 3 μm) were investigated respectively. Commercial tungsten powders (original tungsten powders) were mechanically milled in a high-energy attritor mill for 35 h. Ultra-fine tungsten powders and commercial Ni, Fe powders were consolidated into green compacts by using CIP method and liquid-phase sintering at 1 465 ℃ for 30 min in the dissociated ammonia atmosphere. Liquid-phase sintered tungsten heavy alloys using ultra-fine tungsten powders exhibit full densification (above 99% in relative density) and higher strength and elongation compared with conventional liquidphase sintered alloys using original tungsten powders due to lower sintering temperature at 1 465 ℃ and short sintering time. The mechanical properties of sintered tungsten heavy alloy are found to be mainly dependent on the particles size of raw tungsten powders and liquid-phase sintering temperature.

  19. Mechanical properties and microstructure of Fe3Al intermetallics fabricated by mechanical alloying and spark plasma sintering

    Institute of Scientific and Technical Information of China (English)

    HE Qing; JIA Cheng-chang; MENG Jie

    2006-01-01

    Fabrication technology and mechanical properties of the Fe3Al based alloys were studied by spark plasma sintering from elemental powders (Fe-30Al, volume fraction, %) and mechanically alloying powders. The mechanically alloying powders were processed by the high-energy ball milling the elemental mixture powders with the milling time of 5, 8 and 10 min, respectively. The spark plasma sintering process was performed under the pressure of 50 MPa at 1 050 ℃ for 5 min. The phase identification by X-ray diffraction presents the Fe reacts with Al completely during the processing time. The samples are nearly full density (e.g. the relative density of sinter of raw powder is 99%). The microstructure was observed by TEM. The mechanical properties were tested by three-point bending at room temperature in air. The results show that the mechanical properties are better (e.g. bend strength of 1 500 MPa ) than those of the ordinary Fe3Al casting.

  20. Application of cast nickel alloys for parts of electronics characterised by special magnetic properties

    OpenAIRE

    W. UhI; Z. Pirowski; A. Kułak

    2008-01-01

    Thc thcorctical part of the study highlights thc origin of thc idca 10 start investigations on alloys of high ~nngnctic pcrmcability.manufactured mainly by cornpanics in ~ h Uc S A and Japan.'Phc said materials arc applicd for various pans of ctcctronics uscd by thc military industry. c.g. sntctlitc antcnnas Tor globalcommunication with suhmarincs. and for rcscarch instmrncnts, c,g. fcrromagnctic corcs. Thcy arc chnr:~clcriscd by vcry high lnnpncticpcrrncability. resistivity and corrosion rcs...

  1. Fabrication of low-cost beta-type Ti-Mn alloys for biomedical applications by metal injection molding process and their mechanical properties.

    Science.gov (United States)

    Santos, Pedro Fernandes; Niinomi, Mitsuo; Liu, Huihong; Cho, Ken; Nakai, Masaaki; Itoh, Yoshinori; Narushima, Takayuki; Ikeda, Masahiko

    2016-06-01

    Titanium and its alloys are suitable for biomedical applications owing to their good mechanical properties and biocompatibility. Beta-type Ti-Mn alloys (8-17 mass% Mn) were fabricated by metal injection molding (MIM) as a potential low cost material for use in biomedical applications. The microstructures and mechanical properties of the alloys were evaluated. For up to 13 mass% Mn, the tensile strength (1162-938MPa) and hardness (308-294HV) of the MIM fabricated alloys are comparable to those of Ti-Mn alloys fabricated by cold crucible levitation melting. Ti-9Mn exhibits the best balance of ultimate tensile strength (1046MPa) and elongation (4.7%) among the tested alloys, and has a Young's modulus of 89GPa. The observed low elongation of the alloys is attributed to the combined effects of high oxygen content, with the presence of interconnected pores and titanium carbides, the formation of which is due to carbon pickup during the debinding process. The elongation and tensile strength of the alloys decrease with increasing Mn content. The Ti-Mn alloys show good compressive properties, with Ti-17Mn showing a compressive 0.2% proof stress of 1034MPa, and a compressive strain of 50%.

  2. Fabrication of low-cost beta-type Ti-Mn alloys for biomedical applications by metal injection molding process and their mechanical properties.

    Science.gov (United States)

    Santos, Pedro Fernandes; Niinomi, Mitsuo; Liu, Huihong; Cho, Ken; Nakai, Masaaki; Itoh, Yoshinori; Narushima, Takayuki; Ikeda, Masahiko

    2016-06-01

    Titanium and its alloys are suitable for biomedical applications owing to their good mechanical properties and biocompatibility. Beta-type Ti-Mn alloys (8-17 mass% Mn) were fabricated by metal injection molding (MIM) as a potential low cost material for use in biomedical applications. The microstructures and mechanical properties of the alloys were evaluated. For up to 13 mass% Mn, the tensile strength (1162-938MPa) and hardness (308-294HV) of the MIM fabricated alloys are comparable to those of Ti-Mn alloys fabricated by cold crucible levitation melting. Ti-9Mn exhibits the best balance of ultimate tensile strength (1046MPa) and elongation (4.7%) among the tested alloys, and has a Young's modulus of 89GPa. The observed low elongation of the alloys is attributed to the combined effects of high oxygen content, with the presence of interconnected pores and titanium carbides, the formation of which is due to carbon pickup during the debinding process. The elongation and tensile strength of the alloys decrease with increasing Mn content. The Ti-Mn alloys show good compressive properties, with Ti-17Mn showing a compressive 0.2% proof stress of 1034MPa, and a compressive strain of 50%. PMID:26999621

  3. A novel proposal to manipulate the properties of titanium parts by laser surface alloying

    International Nuclear Information System (INIS)

    A novel proposal is presented to increase the fatigue strength of titanium parts by applying a less rigid coating, which is expected to lower the tensile stresses at the surface and delay the onset of fatigue cracking. Niobium was introduced into the surface layer by laser surface alloying and, depending on the process parameters, β and α″ phases were obtained, resulting in a reduction of approximately 30% in Young’s modulus and a more than 100% increase in hardness

  4. Influence of alloy ingredients on mechanical properties of ternary boride hard alloy clad materials

    Institute of Scientific and Technical Information of China (English)

    LIU Fu-tian; SONG Shi-xue; YANG Jun-ru; HUANG Wei-ling; HUANG Chuan-zhen; CHENG Xin; LI Zhao-qian

    2004-01-01

    Using Mo, B-Fe alloy and Fe powders as raw materials, and adding C, Cr and Ni ingredients, respectively, or C, Cr and Ni mixed powders, ternary boride hard alloy clad materials was prepared on Q235 steel substrate by means of in-situ reaction and vacuum liquid phase sintering technology. The influence of alloy ingredients on the mechanical properties of ternary boride hard alloy clad materials was investigated. The results indicate that a mixture of 0.8% C, 5% Cr and 2% Ni ingredients gives a ternary boride hard alloy clad material with optimal mechanical properties, such as high transverse rupture strength, high hardness and good wear resistance.

  5. Microstructure and mechanical properties control of γ-TiAl(Nb, Cr, Zr) intermetallic alloy by induction float zone processing

    Energy Technology Data Exchange (ETDEWEB)

    Kartavykh, A.V., E-mail: karta@korolev-net.ru [National University of Science and Technology “MISIS”, Leninsky pr. 4, 119049 Moscow (Russian Federation); Technological Institute for Superhard and Novel Carbon Materials (TISNCM), 7a Centralnaya str., 142190 Troitsk, Moscow (Russian Federation); Asnis, E.A.; Piskun, N.V.; Statkevich, I.I. [The E.O. Paton Electric Welding Institute, 11 Bozhenko str., 03680 Kyiv (Ukraine); Gorshenkov, M.V. [National University of Science and Technology “MISIS”, Leninsky pr. 4, 119049 Moscow (Russian Federation)

    2015-09-15

    Highlights: • Induction float zoning of as-synthesized Ti–44Al–5Nb–3Cr–1.5Zr (at.%) alloy. • Special ordered phase microstructure engineering by FZ conditions. • Refining effect by FZ with respect to dissolved oxygen. • Comparative compression testing. • Drastic enhancement of mechanical properties. - Abstract: Advanced Ti–44Al–5Nb–3Cr–1.5Zr (at.%) structural alloy was previously synthesized by the electron beam semi-continuous casting technique. The rod-shaped blanks of raw alloy with irregular coarse microstructure have been directionally upward re-solidified by the vertical induction float zone (FZ) technique in argon flow. FZ processing led to specific duplex microstructure creation consisting of (γ + α{sub 2}) lamellar colonies and γ grains with minor intergranular fraction of B2 phase. The grain size, interlamellar spacing and ordered axial alignment of lamellae along the applied thermal gradient were controlled by FZ conditions. Structure, phase and elemental composition were analyzed with XRD, SEM, EBSD and hot gas extraction techniques. Mechanical properties were comparatively examined by uniaxial compression testing at ambient temperature. It was shown that (1) fine submicron interlamellar spacing; (2) ordered lamellae alignment; (3) relative volumetric ratio of (γ + α{sub 2})/γ/B2 structural-phase constituents and (4) dissolved oxygen content are the key parameters for controlling the compressive properties of FZ-alloy. Both yield strength, and ultimate compressive strength enhance drastically as a result of the FZ processing, being in correlation with the duplex microstructure development and refining of the material from oxygen.

  6. Hydrogenation properties of Mg-Al alloys

    DEFF Research Database (Denmark)

    Andreasen, Anders

    2008-01-01

    . Further, it is found that the kinetics of hydrogenation, as well dehydrogenation, may be significantly improved by alloying compared to pure Mg. The expense of these improvements of the hydrogenation/dehydrogenation properties is a lower gravimetric hydrogen density in the hydrogenated product, (C) 2008...

  7. Microstructure and mechanical properties of wrought magnesium alloy AZ31B welded by laser-TIG hybrid

    Institute of Scientific and Technical Information of China (English)

    刘黎明; 宋刚; 王继锋; 梁国俐

    2004-01-01

    The laser-TIG hybrid welding was mainly used to weld the wrought magnesium alloy AZ31B. The technical characteristics of laser-TIG hybrid welding process was investigated and the interactional mechanism between laser and arc was discussed, at the same time the microstructure and mechanical properties of the wrought magnesium alloy AZ31B using laser-TIG hybrid welding were analyzed by optical microscope, EPMA, SEM, tensile machine, hardness machine. The experimental results show that the presence of laser beam boosts up the stability of the arc during high speed welding and augments the penetration of weld; the crystal grains of magnesium alloy weld are fine without porosity and cracks in the best welding criterion and the microstructure of HAZ does not become coarse obviously. The elements profile analysis reveals that Mg content in the weld is lower than that of the base metal, but Al content is higher slightly. Under this experimental condition, the wrought magnesium alloy AZ31B joint can be achieved using laser-TIG hybrid process and the tensile strength of the joint is equivalent to that of the base metal.

  8. Mechanical and tribological properties of the surface layer of the hot work tool steel obtained by laser alloying

    OpenAIRE

    K. Lukaszkowicz; A. Kriz; E. Jonda; L.A. Dobrzański

    2007-01-01

    Purpose: The paper presents results on the mechanical and tribological properties examinations of the X40CRMoV5-1 hot work alloy tool steel alloyed with carbide powders using the high power diode laser (HPDL).Design/methodology/approach: Metallographic examinations of the material structures after laser alloying of their surface layer were made on light microscope. The tribological wear relationships using pin-on-disc test were specified for surface layers subject to laser treatment, determi...

  9. Mechanical properties of cerium and a cerium–5 wt% lanthanum alloy by nanoindentation and ultrasonic velocity measurements

    Energy Technology Data Exchange (ETDEWEB)

    Wheeler, D.W., E-mail: David.Wheeler@awe.co.uk [AWE, Aldermaston, Reading, Berkshire RG7 4PR (United Kingdom); Zekonyte, J.; Wood, R.J.K. [National Centre for Advanced Tribology Southampton (nCATS), University of Southampton, Highfield, Southampton SO17 1BJ (United Kingdom)

    2013-08-20

    This paper describes a study of the mechanical properties of cerium (Ce) and a cerium–5 wt% lanthanum (Ce–5 wt% La) alloy using nanoindentation and ultrasonic velocity measurements. The materials were also characterised using optical microscopy, energy dispersive spectroscopy, Raman spectroscopy and X-ray diffraction. Despite their propensity to oxidise rapidly in air, both unalloyed Ce and the Ce–5 wt% La alloy have been studied safely in an open laboratory. The hardness and elastic modulus values of the Ce–5 wt% La alloy were slightly higher than those of unalloyed Ce. However, the hardness values of both materials were significantly higher than other values reported in the literature; this was attributed to the presence of cerium oxide inclusions in the microstructure. Reasonable agreement was found between the elastic moduli obtained by nanoindentation and ultrasonic velocity measurements. The mean elastic modulus measured by nanoindentation was, on average, 14% higher than that obtained from the ultrasonic velocity measurements. This work has demonstrated that, with care, Ce can be handled in an open laboratory and meaningful mechanical property data obtained that appear to be free of the influence of the surface oxide layer.

  10. Thermodynamic properties and solidification kinetics of intermetallic Ni7Zr2 alloy investigated by electrostatic levitation technique and theoretical calculations

    International Nuclear Information System (INIS)

    The thermodynamic properties, including the density, volume expansion coefficient, ratio of specific heat to emissivity of intermetallic Ni7Zr2 alloy, have been measured using the non-contact electrostatic levitation technique. These properties vary linearly with temperature at solid and liquid states, even down to the obtained maximum undercooling of 317 K. The enthalpy, glass transition, diffusion coefficient, shear viscosity, and surface tension were obtained by using molecular dynamics simulations. Ni7Zr2 has a relatively poor glass forming ability, and the glass transition temperature is determined as 1026 K. The inter-diffusivity of Ni7Zr2 alloy fitted by Vogel–Fulcher–Tammann law yields a fragility parameter of 8.49, which indicates the fragile nature of this alloy. Due to the competition of increased thermodynamic driving force and decreased atomic diffusion, the dendrite growth velocity of Ni7Zr2 compound exhibits double-exponential relationship to the undercooling. The maximum growth velocity is predicted to be 0.45 m s−1 at the undercooling of 335 K. Theoretical analysis reveals that the dendrite growth is a diffusion-controlled process and the atomic diffusion speed is only 2.0 m s−1

  11. Structure and properties of porous TiNi(Co, Mo)-based alloy produced by the reaction sintering

    Science.gov (United States)

    Artyukhova, Nadezda; Yasenchuk, Yuriy; Chekalkin, Timofey; Gunther, Victor; Kim, Ji-Soon; Kang, Ji-Hoon

    2016-10-01

    Modern medical technologies have developed many new devices that can be implanted into humans to repair, assist or take the place of diseased or defective bones, arteries and even organs. The materials, especially porous ones, used for these devices have evolved steadily over the past twenty years with TiNi-based alloys replacing stainless steels and titanium. The aim of the paper is to presents results for examination of porous TiNi(Co,Mo)-based alloys intended further to be used in clinical practice. The structure and properties of porous TiNi-based alloys obtained by reaction sintering of Ti and Ni powders with additions of Co and Mo have been studied. It has been shown that alloying additions both Co and Mo inhibit the compaction of nickel powders in the initial stage of sintering. The maximum irreversible strain of porous samples under loading in the austenitic state is fixed with the Co addition, and the minimum one is fixed with the Mo addition. The Co addition leads to the fact that the martensite transformation in the TiNi phase becomes close to a one-step, and the Mo addition leads to the fact that the martensite transformation becomes more uniform. Both Co and Mo lead to an increase in the maximum accumulated strain as a result of the formation of temperature martensite. The additional increase in the maximum accumulated strain of the Ti50Ni49Co1 alloy is caused by decreased resistance of the porous Ni γ -based mass during the load.

  12. Properties of a ZK60 magnesium alloy processed by high-pressure torsion

    Energy Technology Data Exchange (ETDEWEB)

    Torbati-Sarraf, Seyed Alireza, E-mail: torbatis@usc.edu [Departments of Aerospace and Mechanical Engineering and Materials Science, University of Southern California, Los Angeles, CA 90089-1453 (United States); Langdon, Terence G. [Departments of Aerospace and Mechanical Engineering and Materials Science, University of Southern California, Los Angeles, CA 90089-1453 (United States); Materials Research Group, Faculty of Engineering and the Environment, University of Southampton, Southampton SO17 1BJ (United Kingdom)

    2014-11-15

    Highlights: • ZK60 magnesium alloy was successfully processed by HPT at room temperature. • HPT for 5 turns led to an equiaxed grain with an average grain size of less than 1 μm. • Homogeneous microstructure were achieved with a hardness of Hv ≈ 124 after 5 turns of HPT at 2.0 GPa. • Superplastic elongations were obtained after HPT for 5 turns at 2.0 GPa. • The maximum elongation was about 535% at 473 K and initial strain rate of 1.0 × 10{sup −4} s{sup −1}. - Abstract: An extruded ZK60 magnesium alloy with an initial grain size of ∼9.4 μm was processed by high pressure torsion (HPT) for up to 5 revolutions and microstructural observations were carried out using optical and scanning electron microscopy. Measurements of the Vickers microhardness over the disk surfaces revealed lower values in the central areas of the disks after low numbers of HPT turns but with a reasonable level of homogeneity across the disks after processing by HPT through 5 turns at 2.0 GPa. The average grain size after 5 revolutions was ∼1.0 μm. Samples were processed by HPT through 5 turns and then tested in tension at a temperature of 473 K. The results show the occurrence of superplastic behavior with a maximum elongation to failure of about 535% when testing with an initial strain rate of 1.0 × 10{sup −4} s{sup −1}. These results are consistent with earlier data obtained on the ZK60 alloy after processing by equal-channel angular pressing (ECAP) but the elongations to failure are lower because of using miniature tensile specimens cut from the HPT disks.

  13. Microstructure and properties of modified and conventional 718 alloys

    Institute of Scientific and Technical Information of China (English)

    LIU Fang; SUN Wen-ru; DU Jin-hui; DONG Jian-xin; GUO Shou-ren; YANG Hong-cai; HU Zhuang-qi

    2006-01-01

    Continuing the effort to redesign IN718 alloy in order to provide microstructural and mechanical stability beyond 650 ℃, IN718 alloy was modified by increasing the Al, P and B contents, and the microstructure and mechanical properties of the modified alloy were compared with those of the conventional alloy by SEM and TEM. The precipitation of the grain boundaries of the two alloys is different. The Cr-rich phase, Laves phase and α-Cr phase are easily observed in the modified alloy. The γ″ and γ′ phases in the modified alloy are precipitated in a "compact form". The tensile strengths of the modified alloy at room temperature and 680 ℃ are obviously higher than those of the conventional one. The impact energy of the modified alloy is only about half of that of the conventional alloy. Ageing at 680 ℃ up to 1 000 h lowers the tensile properties and impact energy of both the conventional and modified 718 alloys, except increasing the ductility at 680 ℃. It is concluded that the modified alloy is more stable than the conventional one.

  14. Influence of mechanical alloying time on the properties of Fe3Al intermetallics prepared by spark plasma sintering

    Institute of Scientific and Technical Information of China (English)

    Chengchang Jia; Qing He; Jie Meng; Lina Guo

    2007-01-01

    The Fe3Al-based intermetallics were prepared by mechanical alloying and spark plasma sintering (SPS), and the influence of milling time on the properties of materials was investigated. The phase identification was investigated by X-ray, and the surface morphology and fractography were observed by scanning electron microscope (SEM). The mechanical properties such as bending strength, strain, and microhardness were tested. The results show that Fe reacts with Al completely to form Fe3Al during short SPS processing time. The relative densities of the sintered samples were nearly 100%. The mechanical properties of the sintered samples can be improved along with the milling time. The representative values are the bend strength of 1327 MPa and the microhardness of 434.

  15. Microstructure and Properties of Lap Joint Between Aluminum Alloy and Galvanized Steel by CMT

    Science.gov (United States)

    Niu, Song; Chen, Su; Dong, Honggang; Zhao, Dongsheng; Zhang, Xiaosheng; Guo, Xin; Wang, Guoqiang

    2016-05-01

    Lap joining of 1-mm-thick Novelist AC 170 PX aluminum alloy to 1.2-mm-thick ST06 Z galvanized steel sheets for automotive applications was conducted by cold metal transfer advanced welding process with ER4043 and ER4047 filler wires. Under the optimized welding parameters with ER4043 filler wire, the tensile shear strength of joint was 189 MPa, reaching 89% of the aluminum alloy base metal. Microstructure and elemental distribution were characterized by optical metalloscope and electron probe microanalysis. The lap joints with ER4043 filler wire had smaller wetting angle and longer bonded line length with better wettability than with ER4047 filler wire during welding with same parameters. The needle-like Al-Fe-Si intermetallic compounds (IMCs) were spalled into the weld and brought negative effect to the tensile strength of joints. With increasing welding current, the needle-like IMCs grew longer and spread further into the weld, which would deteriorate the tensile shear strength.

  16. Changes of inclusion, texture and magnetic property of non-oriented Si steel treated by Ca alloy

    Science.gov (United States)

    Lv, X.; Zhang, F.; Chen, X.

    2015-04-01

    Based on the industrial production of non-oriented Si steel, Ca treatment by Ca alloy adding during the RH refining process was studied. The changes of inclusion, crystal texture and microstructure, and its effect on magnetic properties of final steel sheets were analyzed. The results showed that, in present work, Ca treatment can improve the texture proportion of {110} and {111} significantly, and the formation of MnS and AlN inclusions were restrained. Meanwhile, the recrystallization effects of hot rolled strip get bad and the fiber structure enhanced obviously. The grain size of finished steel sheets increased as the increase of Ca alloy adding amount quickly, and then decreased. Compared with the non-Ca treatment charge, the numbers of inclusions whose size below 1.0μm will decrease by 68.06%, 87.50% and 94.94%, the texture proportion of {110} and {111} was 30.3%, 39.1%, 17.6% and 2.8%, 5.5%, 20.6%, while the correspondent Ca alloy adding amount is 0.67 kg/t steel, 1.00 kg/t steel and 1.67 kg/t steel, respectively. In addition, the core loss gradually decreases to a stable level as the increasing of Ca added, and the magnetic induction decreases quickly after slow increasing, respectively. The optimal Ca treatment mode depends on the chemical compositions of steel grades.

  17. Influence of annealing on microstructure and magnetic properties of cobalt-based amorphous/nanocrystalline powders synthesized by mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Taghvaei, Amir Hossein, E-mail: Amirtaghvaei@gmail.com [Department of Materials Science and Engineering, Shiraz University of Technology, Shiraz (Iran, Islamic Republic of); Bednarčik, Jozef [Photon Science DESY, Notkestraße 85, 22603 Hamburg (Germany); Eckert, Jürgen [IFW Dresden, Institute for Complex Materials, Helmholtzstr. 20, 01069 Dresden (Germany); TU Dresden, Institute of Materials Science, 01062 Dresden (Germany)

    2015-05-25

    Highlights: • Structural relaxation in mechanically alloyed Co{sub 40}Fe{sub 22}Ta{sub 8}B{sub 30} powders was studied. • Isochronal annealing notably changes the short-range order of the amorphous phase. • The medium-range correlations experienced volume shrinkage upon annealing. • Annealing decreased the coercivity and saturation magnetization of the powders. - Abstract: The effects of isochronal annealing on microstructure and magnetic properties of Co{sub 40}Fe{sub 22}Ta{sub 8}B{sub 30} powders with a large content of amorphous phase produced by mechanical alloying have been investigated. The differential scanning calorimetry (DSC) results indicate that the synthesized powders exhibit a huge exothermic reaction before the crystallization temperature corresponding to structural relaxation of amorphous phase. Furthermore, the structural evolution of the powders upon isochronal heating has been investigated by in-situ X-ray diffraction (XRD) using high energy synchrotron radiation. The occurrence of an irreversible structural relaxation is confirmed by significant changes in position of the first and second diffuse maxima of the total structure factor S(Q) upon isochronal heating–cooling cycles. Moreover, analysis of the reduced pair distribution functions (PDFs) yields a volume shrinkage of about 1.5% after annealing due to annihilation of the excess free volume generated upon milling. The isochronal annealing significantly affects the magnetic properties of the powders through decreasing the saturation magnetization and coercivity. The correlation between structural relaxation and magnetic properties of the powders is discussed.

  18. Structure and properties of nitrided surface layer produced on NiTi shape memory alloy by low temperature plasma nitriding

    Energy Technology Data Exchange (ETDEWEB)

    Czarnowska, Elżbieta [Children' s Memorial Health Institute, Pathology Department, Al. Dzieci Polskich 20, 04-730 Warsaw (Poland); Borowski, Tomasz [Warsaw University of Technology, Faculty of Materials Science and Engineering, Wołoska 141, 02-507 Warsaw (Poland); Sowińska, Agnieszka [Children' s Memorial Health Institute, Pathology Department, Al. Dzieci Polskich 20, 04-730 Warsaw (Poland); Lelątko, Józef [Silesia University, Faculty of Computer Science and Materials Science, 75 Pułku Piechoty 1A, 41-500 Chorzów (Poland); Oleksiak, Justyna; Kamiński, Janusz; Tarnowski, Michał [Warsaw University of Technology, Faculty of Materials Science and Engineering, Wołoska 141, 02-507 Warsaw (Poland); Wierzchoń, Tadeusz, E-mail: twierz@inmat.pw.edu.pl [Warsaw University of Technology, Faculty of Materials Science and Engineering, Wołoska 141, 02-507 Warsaw (Poland)

    2015-04-15

    Highlights: • Low temperature plasma nitriding process of NiTi shape memory alloy is presented. • The possibility of treatment details of sophisticated shape. • TiN surface layer has diffusive character. • TiN surface layer increases corrosion resistance of NiTi alloy. • Produced TiN layer modify the biological properties of NiTi alloy. - Abstract: NiTi shape memory alloys are used for bone and cardiological implants. However, on account of the metallosis effect, i.e. the release of the alloy elements into surrounding tissues, they are subjected to various surface treatment processes in order to improve their corrosion resistance and biocompatibility without influencing the required shape memory properties. In this paper, the microstructure, topography and morphology of TiN surface layer on NiTi alloy, and corrosion resistance, both before and after nitriding in low-temperature plasma at 290 °C, are presented. Examinations with the use of the potentiodynamic and electrochemical impedance spectroscopy methods were carried out and show an increase of corrosion resistance in Ringer's solution after glow-discharge nitriding. This surface titanium nitride layer also improved the adhesion of platelets and the proliferation of osteoblasts, which was investigated in in vitro experiments with human cells. Experimental data revealed that nitriding NiTi shape memory alloy under low-temperature plasma improves its properties for bone implant applications.

  19. Dynamic property evaluation of aluminum alloy 2519A by split Hopkinson pressure bar

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xin-ming; LI Hui-jie; LI Hui-zhong; GAO Hui; GAO Zhi-guo; LIU Ying; LIU Bo

    2008-01-01

    Impact behavior of aluminum alloy 2519A was investigated at strain rates of 600-7 000 s-1 and temperatures of 20-450 ℃ by a split Hopkinson pressure bar. The results show that the flow stress is dominated by temperature, and it increases with strain rate and decreases with deformation temperature. The serrated flow curves show the dynamic recrystallization occurs. The strain rate sensitivity exponents m determined are 0.066, 0.059 4, 0.059 0 and 0.057 3 at 20, 150, 300 and 450 ℃, respectively. Cowper- Symonds constitutive equation expressing the plastic flow behavior was calculated by analysis and regression of the experimental results. The fracture characteristics under the experimental conditions were observed by optical microscopy(OM) and scanning electron microscopy(SEM). It is determined that the tested material fails as a result of adiabatic shearing.

  20. Microstructure and mechanical properties of multiphase layer formed during depositing Ti film followed by plasma nitriding on 2024 aluminum alloy

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, F.Y., E-mail: zfy19861010@163.com; Yan, M.F., E-mail: yanmufu@hit.edu.cn

    2014-05-01

    Highlights: • A novel duplex surface treatment on 2024 Al alloy was proposed. • A multiphase layer composed of TiN{sub 0.3}, Al{sub 3}Ti and Al{sub 18}Ti{sub 2}Mg{sub 3} was prepared on the surface of 2024 Al alloy. • The microstructures of TiN{sub 0.3}, Al{sub 3}Ti and Al{sub 18}Ti{sub 2}Mg{sub 3} were characterized by SEM and TEM. • The surface hardness of the multiphase layer reached to 590 HV{sub 0.01}, five times harder than 2024 Al alloy. • The wear resistance of 2024 Al alloy was improved significantly. - Abstract: In this study, a novel method was develop to fabricate an in situ multiphase layer on 2024 Al alloy to improve its surface mechanical properties. The method was divided into two steps, namely depositing pure Ti film on 2024 Al substrate by using magnetron sputtering, and plasma nitriding of Ti coated 2024 Al in a gas mixture comprising of 40% N{sub 2}–60% H{sub 2}. The microstructure and mechanical properties of the multiphase layer prepared at different nitriding time were investigated by using X-ray diffractometer (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM), microhardness tester and pin-on-disc tribometer. Results showed that multiphase layer with three sub-layers (i.e. the outmost TiN{sub 0.3} layer, the intermediate Al{sub 3}Ti layer and the inside Al{sub 18}Ti{sub 2}Mg{sub 3} layer) can be obtained. The thickness of the Al{sub 18}Ti{sub 2}Mg{sub 3} layer increased faster than TiN{sub 0.3} and Al{sub 3}Ti layer with increasing nitriding time. The hardness of the layer has reached about 593 HV, which is much higher than that of 2024 Al substrate. The wear rate of the coated samples decreased 53% for 4 h nitriding and 86% for 12 h nitriding, respectively, compared with that of the uncoated one. The analysis of worn surface indicated that the coated 2024 Al exhibited predominant abrasive wear, whereas the uncoated one showed severe adhesive wear.

  1. Properties Of MgB2/Ga Composites Prepared By Mechanical Alloying

    Directory of Open Access Journals (Sweden)

    Yoon K.

    2015-06-01

    Full Text Available In this study, we examined the effect of Ga-doping and mechanical alloying in MgB2 on microstructural and phase evolution. A comparison was made between in-situ and ex-situ processed Mg-B-Ga samples. Densification was markedly improved by ex-situ sintering of ball-milled MgB2+Ga. The Ga-doping and ball-milling prior to sintering resulted in the formation of impurity phases such as MgO, Ga5Mg2 and Ga2O3. Lattice parameter of MgB2 increased with increasing ball-milling duration as well as by Ga-doping.

  2. Textures and mechanical properties in rare-earth free quasicrystal reinforced Mg-Zn-Zr alloys prepared by extrusion

    International Nuclear Information System (INIS)

    Highlights: → Powder-metallurgical warm extrusion made quasicrystal dispersing Mg alloys. → Mg extrusions containing quasicrystals showed randomized textures. → These extrusion showed the enhancement of mechanical properties at 150 deg. C. - Abstract: Microstructure and mechanical properties of quasicrystals dispersed Mg alloys prepared by warm extrusion of the mixtures of Mg and Zn-Mg-Zr quasicrystalline (Qc) powders have been studied. Strong texture oriented along a [101-bar 0] direction observed in pure Mg was reduced in Qc-dispersed samples, as verified by pole figure method and electron back scattering diffraction. The ultimate tensile strengths at 150 deg. C for Qc-dispersed extrusions were much higher than 110 MPa for pure Mg, which drastically reached 156 MPa for 15 wt.% Qc by preventing the motion of dislocations. Elongation was improved by the randomization of grain orientation: from 5.7% for pure Mg to 12.9% for 10 wt.% Qc at room temperature; from 15% for pure Mg to 37.1% for 5 wt.% Qc at 150 deg. C.

  3. Microstructure, Mechanical Properties, and Texture Evolution of Aluminum Alloy 7005 by Accumulative Roll Bonding

    Science.gov (United States)

    Xie, Hu; Wang, M. P.; Chen, Wei; Jia, Yanlin

    2016-03-01

    In the present work, the accumulative roll bonding process was carried out on a 7005 aluminum alloy sheet to six passes. The microstructure and texture evolution was investigated by transmission electron microscope, electron backscatter diffraction analysis, and x-ray texture goniometer. With the increase of ARB passes, the microstructure was refined and the fraction of high angle boundaries increased. The hardness of different ARB process specimens was measured and showed that as the ARB passes increased, the hardness rose obviously. The tensile strength of 6 passes reaches 423.4 MPa and the elongation is 4.6%. The material is strongly textured where individual layers possess typical FCC rolling texture components and the variation of each texture is different. This is attributed to the microstructure evolution during the ARB process.

  4. Microstructure and property of a functionally graded aluminum silicon alloy fabricated by semi-solid backward extrusion process

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Kai [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Yu, Hao, E-mail: yhzhmr@126.com [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Liu, Jun-you [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Li, Yan-xia [Department of Materials, North China Institute of Aerospace Engineering, Langfang 065000 (China); Liu, Jian; Zhang, Jia-liang [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China)

    2015-01-29

    In this paper, the microstructure and mechanical property of a graded aluminum silicon alloy were investigated and a new preparation method for the graded material was proposed. The cup-shaped sample was fabricated by the backward extrusion process during the semi-solid state of A390 cast alloy. Characteristics and distribution of the primary particles were assessed by the optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive spectrum (EDS) and image analyzer software. The results showed that the content of primary Si gradually decreased from the bottom region to the upper region. The hardness and wear rate of the samples were measured to evaluate the variation in the mechanical properties corresponding to the variation in microstructure. The hardness values and wear resistance along the axis of the cup-shaped sample gradually increased from the upper region to the bottom region and from the inner region to the outer layer, respectively. The maximum average hardness value is 138.7 HB. The observations of fracture surface were analyzed by scanning electron microscopy to understand the fracture mechanism. The results also indicated that the ultimate tensile strength (UTS) of the graded material after T6 treatment are 275 MPa, increases 32.3% compared to the original backward extrusion alloy. Optical microscopy and electron probe micro-analyzer were used to study the distribution of elements and the microstructure of different intermetallic phases formed. Electron microprobe analysis (EMPA) results showed that the content of the prominent elements (Cu, Fe, Mg) in the upper region was higher than for the bottom part of the cup-shaped specimens.

  5. Predicting the properties of the lead alloys from DFT calculations

    Energy Technology Data Exchange (ETDEWEB)

    Buimaga-Iarinca, L., E-mail: luiza.iarinca@itim-cj.ro; Calborean, A. [National Institute for Research and Development of Isotopic and Molecular Technologies, 67-103 Donat, 400293 Cluj-Napoca (Romania)

    2015-12-23

    We provide qualitative results for the physical properties of the lead alloys at atomic scale by using DFT calculations. Our approach is based on the two assumptions: (i) the geometric structure of lead atoms provides a matrix where the alloying elements can take their positions in the structure as substitutions and (ii) there is a small probability of a direct interaction between the alloying elements, thus the interactions of each alloying element may be approximated by the interactions to the lead matrix. DFT calculations are used to investigate the interaction between several types of impurities and the lead matrix for low concentrations of the alloying element. We report results such as the enthalpy of formation, charge transfer and mechanical stress induced by the impurities in the lead matrix; these results can be used as qualitative guide in tuning the physico-chemical properties of the lead alloys.

  6. Improvement in hydriding property of LaNi{sub 4.8}Al{sub 0.2} alloy encapsulated by SiO{sub 2} sol

    Energy Technology Data Exchange (ETDEWEB)

    Qian, Xiaojing, E-mail: eagleqq@sina.com; Huang, Guoqiang

    2014-12-15

    Highlights: • LaNi{sub 4.8}Al{sub 0.2} powder can be enwrapped in the SiO{sub 2} network effectively. • Fine pores can restrict impurities entering into matrix avoiding metal poisoning. • Anti-pulverization property of LaNi{sub 4.8}Al{sub 0.2} is enhanced after being encapsulated. • Anti-poisoning property of LaNi{sub 4.8}Al{sub 0.2} is enhanced after being encapsulated. - Abstract: LaNi{sub 4.8}Al{sub 0.2} alloy particles encapsulated by SiO{sub 2} matrix were prepared by the sol gel method. Scanning electron microscope (SEM) imaging was applied to determine the silica network outside the encapsulated alloy. The hydriding kinetics, pulverization and poisoning characteristics of LaNi{sub 4.8}Al{sub 0.2} alloy were investigated before and after being encapsulated by silica. The results reveal that the hydriding properties of encapsulated alloy are excellent. The hydrogenation rate of encapsulated alloy is faster than that of the original alloy. The quantities of hydrogen stored by the encapsulated and original alloy are 169.3 Nml/g and 147.1 Nml/g, respectively. The LaNi{sub 4.8}Al{sub 0.2} alloy particles are broken up into powder after 10 times hydrogen absorption/desorption cycles, while the encapsulated alloy do not show any breakdown after 30 times hydrogen adsorption/desorption cycles. The quantities of hydrogen absorbed by original alloy particles are less than 8.2 Nml/g in H{sub 2}-14.4% CO and 18.6 Nml/g in H{sub 2}-12.8% CO{sub 2}, while the quantities of hydrogen absorbed by encapsulated alloy agglomerations are 84.5 Nml/g in H{sub 2}-14.4% CO and 168.9 Nml/g in H{sub 2}-12.8% CO{sub 2}. These results clearly indicate that the pulverization and poisoning resistance properties of LaNi{sub 4.8}Al{sub 0.2} alloy are evidently enhanced after being encapsulated by silica network.

  7. Comparison of Microstructure and Properties of Ti-6Al-7Nb Alloy Processed by Different Powder Metallurgy Routes

    OpenAIRE

    Bolzoni, Leandro; Hari Babu, N; Ruiz Navas, Elisa María; Gordo Odériz, Elena

    2013-01-01

    Proceedings of: The Minerals, Metals and Materials Society 2013: 142nd Annual meeting and Exhibition. San Antonio, Texas, USA, March 3-7, 2013. The Ti-6Al-7Nb alloy was specially developed to replace the well-known Ti-6Al-4V alloy in biomedical applications due to supposed cytotoxicity of vanadium in the human body. This alloy is normally fabricated by conventional ingot metallurgy by forging bulk material. Nevertheless, powder metallurgy techniques could be used to obtain this alloy with ...

  8. Structural and mechanical properties of EN AW 6082 aluminum alloy produced by equal-channel angular pressing

    OpenAIRE

    Greger, Miroslav; Madaj, Michal; Žáček, David

    2014-01-01

    At the VSB-TU Ostrava a piece of equipment was installed for verifying the equal-channel-angular-pressing (ECAP) technology, used for investigating the effect of deformation on the evolution of the structure and mechanical properties of alloy EN AW 6082. This alloy was subjected to ECAP consisting of four passes. During the pressing deformation forces were measured and the pressure in the die was calculated. Higher values of strain hardening were found and a higher pressure was me...

  9. Influence of copper content on the property of Cu–W alloy prepared by microwave vacuum infiltration sintering

    International Nuclear Information System (INIS)

    Highlights: • Cu–W alloy was prepared under vacuum conditions through microwave infiltration sintering. • The phase of alloy with Cu content of 5% and 8% is mainly Cu0.4W0.6. • With the increasing of copper content, porosity of Cu–W alloy decreased obviously. • The copper components coated better on the tungsten particles utilization of microwave infiltration sintering. - Abstract: Cu–W alloy was prepared by utilizing microwave vacuum infiltration sintering furnace to assess the influence of different proportions of copper on the structure of Cu–W alloy. The microstructures of alloy and infiltration characteristics of Cu–W alloy were characterized using metallographic microscopy and scanning electron microscopy, while XRD was utilized to identify the structure changes. The pore distribution was also assessed. Experimental results showed that Cu–W alloy could be quickly prepared under vacuum conditions through microwave infiltration sintering with the main phase of alloy being Cu0.4W0.6 (PDF:50-1451) indicating stronger combination of tungsten and copper

  10. Structural analysis and magnetic properties of solid solutions of Co–Cr system obtained by mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Betancourt-Cantera, J.A. [Área Académica de Ciencias de la Tierra y Materiales, UAEH Carr., Pachuca-Tulancingo Km. 4.5, Pachuca, Hidalgo 42184 (Mexico); Sánchez-De Jesús, F., E-mail: fsanchez@uaeh.edu.mx [Área Académica de Ciencias de la Tierra y Materiales, UAEH Carr., Pachuca-Tulancingo Km. 4.5, Pachuca, Hidalgo 42184 (Mexico); Bolarín-Miró, A.M. [Área Académica de Ciencias de la Tierra y Materiales, UAEH Carr., Pachuca-Tulancingo Km. 4.5, Pachuca, Hidalgo 42184 (Mexico); Betancourt, I.; Torres-Villaseñor, G. [Departamento de Materiales Metálicos y Cerámicos, Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, México D.F. 04510 (Mexico)

    2014-03-15

    In this paper, a systematic study on the structural and magnetic properties of Co{sub 100−x}Cr{sub x} alloys (0by mechanical alloying is presented. Co and Cr elemental powders were used as precursors, and mixed in an adequate weight ratio to obtain Co{sub 1−x}Cr{sub x} (0by the Cr content and by the competition between ferromagnetic and antiferromagnetic exchange interactions. The coercivity increases up to 34 kA/m (435 Oe) for Co{sub 40}Cr{sub 60}. For Cr rich compositions, it is observed an important decrease reaching 21 kA/m (272 Oe) for Co{sub 10}Cr{sub 90,} it is related to the grain size and the structural change. Besides, the magnetic anisotropy constant was determined for each composition. Magnetic thermogravimetric analysis allowed to obtain Curie temperatures corresponding to the formation of hcp-Co(Cr) and fcc-Co(Cr) solid solutions. - Highlights: • Mechanical alloying (MA) induces the formation of solid solutions of Co–Cr system in non-equilibrium. • We report the crystal structure and the magnetic behavior of Co–Cr alloys produced by MA. • MA improves the magnetic properties of Co–Cr system.

  11. Structure and optical properties of ternary alloy BeZnO and quaternary alloy BeMgZnO films growth by molecular beam epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Su, Longxing, E-mail: sulx@mail2.sysu.edu.cn [State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yet-Sen University, Guangzhou 510275 (China); Zhu, Yuan, E-mail: zhuy9@mail.sysu.edu.cn [State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yet-Sen University, Guangzhou 510275 (China); Physics Department, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon (Hong Kong); Zhang, Quanlin; Chen, Mingming; Wu, Tianzhun; Gui, Xuchun [State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yet-Sen University, Guangzhou 510275 (China); Pan, Bicai [Department of Physics and Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui 230026 (China); Xiang, Rong [State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yet-Sen University, Guangzhou 510275 (China); Tang, Zikang, E-mail: phzktang@ust.hk [State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yet-Sen University, Guangzhou 510275 (China); Physics Department, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon (Hong Kong)

    2013-06-01

    Ternary alloy BeZnO and quaternary alloy BeMgZnO films were prepared on sapphire (0 0 1) substrate by radio-frequency plasma-assisted molecular beam epitaxy (RF-PAMBE). Based on X-ray diffraction (XRD) analysis, no phase segregation is observed for all the alloys. However, Be{sub x}Zn{sub 1−x}O alloys exhibit a constantly worse crystal quality than Be{sub x}Mg{sub y}Zn{sub 1−x−y}O alloys at the similar incorporation contents (i.e. x in BeZnO approximately equals to x + y in BeMgZnO). Optical transmittance spectra were recorded to determine the energy band gap of the films. BeMgZnO was revealed more effective in widening the band gap. Finally, BeZnO and BeMgZnO based MSM structure UV detectors were fabricated. BeMgZnO alloys with better crystal quality showed a favorable optical response and the cutoff wavelength shifted continuously to deep ultraviolet range, while BeZnO based detectors were found no response. This is the first report on BeMgZnO based UV detector, which is a meaningful step forward to the real application.

  12. Fatigue properties of alloy 718 overlay-coated with a Co-based X40 alloy by the Micro Spark Coating

    Science.gov (United States)

    Kamma, Ryohta; Sakaguchi, Motoki; Okazaki, Masakazu; Shimoda, Yukihiro; Uchiyama, Takehiko; Ochiai, Hiroyuki; Watanabe, Mitsutoshi

    Micro Spark Coating (MSC) has been developed as a new functional coating process for Ni-based superalloys used in advanced gas turbines. In this study, some metallurgical and mechanical properties of a MSC layer made of a Co-based wear resisting alloy (X40), and its influence on the high temperature fatigue properties of Ni-based superalloy, Alloy718, were investigated. Prior evaluation of the metallurgical and mechanical properties of the MSC layer that the cavity fraction of MSC layer significantly decreased during the thermal exposure period at 650°C associating with the generation of an oxide phase, progressive sintering and the subsequent increase in hardness and elastic modulus of MSC layer. However, at 480°C these changes were not significant even after 1000hrs exposure. It was found from the high temperature fatigue tests at 480°C and 650°C that the fatigue life of the specimen with MSC layer was almost comparable to that of bare Alloy718 specimen at 480°C, while at 650°C the life of the former was slightly longer than that of the latter. These results suggested that the MSC would have a potential to add a new function to Ni-based superalloy without a reduction in fatigue properties at elevated temperature.

  13. Effect of alloying addition and microstructural parameters on mechanical properties of 93% tungsten heavy alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ravi Kiran, U., E-mail: uravikiran@gmail.com [Defence Metallurgical Research Laboratory, Kanchanbagh, Hyderabad 500 058 (India); Panchal, A.; Sankaranarayana, M. [Defence Metallurgical Research Laboratory, Kanchanbagh, Hyderabad 500 058 (India); Nageswara Rao, G.V.S. [National Institute of Technology, Warangal 506004 (India); Nandy, T.K. [Defence Metallurgical Research Laboratory, Kanchanbagh, Hyderabad 500 058 (India)

    2015-07-29

    Liquid phase sintering, heat treatment and swaging studies on three tungsten heavy alloys, 93W–4.9Ni–2.1Fe (wt%), 93W–4.2Ni–1.2Fe–1.6Co (wt%) and 93W–4.9Ni–1.9Fe–0.2Re (wt%) were carried out in detail with respect to microstructure, tensile and impact properties. All the alloys were sintered and swaged to 40% deformation. The results indicate that Re addition reduces the grain size of the alloy compared to W–Ni–Fe and W-Ni-Fe-Co alloys. W–Ni–Fe–Re alloy shows superior tensile properties in heat treated condition as compared to W–Ni–Fe and W–Ni–Fe–Co alloys. SEM study of fractured specimens clearly indicates that the failure in case of W–Ni–Fe–Re was due to transgranular cleavage of tungsten grains and W–W de-cohesion. W–Ni–Fe and W–Ni–Fe–Co alloys also failed by mixed mode failure. However, in these cases, ductile dimples corresponding the failure of the matrix phase was rarely seen. Thermo-mechanical processing resulted in significant changes in mechanical properties. While W–Ni–Fe–Re alloy showed the highest tensile strength (1380 MPa), W–Ni–Fe–Co exhibited the highest elongation (12%) to failure. A detailed analysis involving microstructure, mechanical properties and failure behavior was undertaken in order to understand the property trends.

  14. Improvement of mechanical and biological properties of TiNi alloys by addition of Cu and Co to orthodontic archwires.

    Science.gov (United States)

    Phukaoluan, Aphinan; Khantachawana, Anak; Kaewtatip, Pongpan; Dechkunakorn, Surachai; Kajornchaiyakul, Julathep

    2016-09-01

    The purpose of this study was to investigate improved performances of TiNi in order to promote tooth movement. Special attention was paid to the effect on the clinical properties of TiNi of adding Cu and Co to this alloy. Ti49.4Ni50.6, Ti49Ni46Cu5 and Ti50Ni47Co3 (at %) alloys were prepared. Specimens were cold-rolled at 30% reduction and heat-treated at 400°C for 60min. Then, the test results were compared with two types of commercial archwires. The findings showed that superelasticity properties were confirmed in the manufactured commercial alloys at mouth temperature. The difference of stress plateau in TiNi, TiNiCo and commercial wires B at 25°C changed significantly at various testing temperatures due to the combination of martensite and austenite phases. At certain temperatures the alloys exhibited zero recovery stress at 2% strain and consequently produced zero activation force for moving teeth. The corrosion test showed that the addition of Cu and Co to TiNi alloys generates an increase in corrosion potential (Ecorr) and corrosion current densities (Icorr). Finally, we observed that addition of Cu and Co improved cell viability. We conclude that addition of an appropriate amount of a third alloying element can help enhance the performances of TiNi orthodontic archwires. PMID:27520713

  15. Evolution of structure, microstructure and hyperfine properties of nanocrystalline Fe50Co50 powders prepared by mechanical alloying

    International Nuclear Information System (INIS)

    Nanostructured Fe50Co50 powders were prepared by mechanical alloying of Fe and Co elements in a vario-planetary high-energy ball mill. The structural properties, morphology changes and local iron environment variations were investigated as a function of milling time (in the 0-200 h range) by means of X-ray diffraction, scanning electron microscopy (SEM), energy dispersive X-ray analysis and 57Fe Moessbauer spectroscopy. The complete formation of bcc Fe50Co50 solid solution is observed after 100 h milling. As the milling time increases from 0 to 200 h, the lattice parameter decreases from 0.28655 nm for pure Fe to 0.28523 nm, the grain size decreases from 150 to 14 nm, while the meal level of strain increases from 0.0069% to 1.36%. The powder particle morphology at different stages of formation was observed by SEM. The parameters derived from the Moessbauer spectra confirm the beginning of the formation of Fe50Co50 phase at 43 h of milling. After 200 h of milling the average hyperfine magnetic field of 35 T suggests that a disordered bcc Fe-Co solid solution is formed. - Highlights: → Nanostructured Fe50Co50 powders were successfully prepared by mechanical alloying process. → Final average grain size value achieved after 200 h of milling was 14 nm. → For the longest milling time the majority of particle grains observed by SEM exhibits a round shape with small diameter.

  16. Dynamic Compression Properties of an Ultrafine-Grained Al-26 wt.% Si Alloy Fabricated by Equal-Channel Angular Pressing

    Science.gov (United States)

    Jiang, Jinghua; Shi, Jun; Yao, YiHong; Ma, Aibin; Song, Dan; Yang, Donghui; Chen, Jianqing; Lu, Fumin

    2015-05-01

    The grains of a hypereutectic Al-26 wt.% Si alloy were drastically refined by multi-pass equal-channel angular pressing (ECAP). Compression deformation characteristics of the alloy with different microstructure were examined at two dynamic strain rates (700, 1000 s-1) by a split-Hopkinson pressure bar system and at a quasi-static strain rate (0.001 s-1) by a universal testing machine, respectively. The results reveal that the Al-26 wt.% Si alloy is strain-rate sensitive under those compression conditions, i.e., the initial yield stress and the flow stress considerably increase with the strain rate. Grain refinement through ECAP improves the strain-rate sensitivity of the alloy. With rising the ECAP temperature, the yield stress of the ultrafine-grained alloy decreases but the strain value increases during dynamic compression.

  17. Cast bulk glassy alloys:fabrication,alloy development and properties

    Institute of Scientific and Technical Information of China (English)

    Qingsheng Zhang; Chunling Qin; Akihisa Inoue

    2010-01-01

    Metallic glasses represent an interesting group of materials as they possess outstanding physical, chemical and mechanical properties compared to their crystalline counterparts. Currently, with well designed compositions it is possible to cast liquid alloys into the glassy state at low critical cooling rates from 100 K·s-1 to 1 K·s-1 and in large critical sample sizes up to several centimeters, which significantly enhances the promise for possible applications as advanced engineering materials. This paper reviews the development of(ZrCu)-based bulk metallic glasses with large sizes by copper mold casting and their unique properties. Additionally, the ex-situ and in-situ second phases reinforced BMG composites with large plasticity are also presented.

  18. Properties Evaluation and Studying Production Mechanism of Nanocrystalline NiAl Intermetallic Compound by Mechanical Alloying

    Science.gov (United States)

    Khajesarvi, Ali; Akbari, Golamhossein

    2016-04-01

    Ni50Al50 intermetallic compound was synthesized by mechanical alloying (MA) of elemental mixtures of Ni and Al powders in a planetary ball mill. After 16 hours of milling and obtaining crystallites with a critical size, the initial NiAl compound was formed along with the combustive reaction after opening the vial lid. In the time interval of 16 to 128 hours, the reaction from combustive state reached the explosive state. Finally, after 128 hours of milling, the initial powders were wholly transformed into NiAl before completion of the milling time. Structural changes of powder particles during MA were studied by X-ray diffractometry and scanning electron microscopy. The crystallite size measurements revealed that the grain size of the NiAl phase decreased from 155 to 26 nm with increasing MA time from 8 to 128 hours. Microhardness for nanocrystalline Ni50Al50 intermetallic compound produced after 128 hours of milling was measured as about 350 Hv.

  19. Lubrication properties of silver-palladium alloy prepared by ion plating method for high temperature stud bolt

    Institute of Scientific and Technical Information of China (English)

    Jung-Dae KWON; Sunghun LEE; Koo-Hyun LEE; Jong-Joo RHA; Kee-Seok NAN; Se-Hun KWON

    2011-01-01

    As a solid lubricant, silver-palladium (Ag-Pd) alloy coating was investigated for the application to high temperature studbolt. A glue layer nickel (Ni) film was deposited on the surface of the hex bolt sample and then Ag-Pd alloy coating was performed on it using ion plating method. The friction coefficient of Ag-Pd alloy film coated bolt was lower than that of N-5000 oil coated bolt by the result of axial force measurement. The cyclic test of heat treatment was conducted to evaluate the durability of Ag-Pd alloy film coated bolt. In a cycle, sample was assembled into the block using torque wrench, followed by heating and disassembling. It was not successful to disassemble the N-5000 oil coated bolt from the block after only one cycle. However, the Ag-Pd alloy film coated bolt was able to be disassembled softly till 12 cycles.

  20. Mechanical properties of AZ31 alloy processed by a green metallurgy route; Propiedades mecanicas de la aleacion AZ31 procesada por una ruta eco-sostenible

    Energy Technology Data Exchange (ETDEWEB)

    D' Enrico, F.; Garces, G.; Hofer, M.; Kim, S. K.; Perez, P.; Cabeza, S.; Adeva, P.

    2013-07-01

    Recently it has been proved that molding of defect-free components of various commercial alloys of magnesium can be carried out successfully when small amounts of CaO are added to the melt, making unnecessary the use of SF{sub 6} coverage. In the case of AZ alloys, this process also remarkably improves their mechanical properties not only by the greater cleaning of alloys but also by the formation of CaAl{sub 2} phase. This work, part of the Green project Metallurgy (http://www.green-metallurgy.eu) funded by the European Union (LIFE+2009), studies the influence of different CaO additions on the microstructure and mechanical properties of AZ31 Eco-Mg alloy. The alloy was processed by a conventional route involving extrusion of as-cast rods as well as by a powder metallurgy route (PM) using chips as starting material. The objective was to analyze the viability of recycling machining chips to manufacture components for the automobile industry and transportation in general, because of its low cost and environmental impact. It has been demonstrated that alloys processed from chips exhibit the highest tensile stress values, close to 320 MPa. (Author)

  1. Microstructural and magnetic properties of Nd-Fe-B alloys processed by equal-channel angular pressing

    Science.gov (United States)

    Onal, E.; Lapovok, R.; Kishimoto, H.; Kato, A.; Davies, C. H. J.; Suzuki, K.

    2015-05-01

    Equal-channel angular pressing (ECAP) is a well-established thermo-mechanical processing technique. This technique allows virtually unlimited strain and manipulation of texture by processing route, while the cross-section of the sample remains unchanged during processing. In order to clarify the effectiveness of ECAP on preparing anisotropic permanent magnets, the microstructure and magnetic properties of a melt-spun Nd13.5Fe73.8Co6.7B5.6Ga0.4 alloy processed at 773 K for 300 s by ECAP were investigated. Macrotexture analysis carried out for the exit channel of ECAP shows that the basal plane of the tetragonal Nd2Fe14B crystal aligns parallel to the shear band, i.e., the c-axis texture formation normal to the shear band induced by the ECAP process. Due to this texture formation, the technical magnetization behaviour becomes anisotropic, and the remanent magnetization is clearly enhanced along the direction perpendicular to the shear band. This anisotropic microstructure is realized at a relatively low processing temperature of 773 K, well below the melting point of the Nd-rich intergranular phase. As a consequence of this lower processing temperature, the nanostructure of the melt-spun alloy remains approximately 20 to 30 nm, considerably smaller than the typical grain size obtained after conventional die-upsetting. Our study demonstrates that equal-channel angular pressing has a potential for realising anisotropic nanostructured magnets.

  2. Microstructure and mechanical properties of 7075 aluminum alloy nanostructured composites processed by mechanical milling and indirect hot extrusion

    International Nuclear Information System (INIS)

    Nanostructured composites of 7075 aluminum alloy and carbon coated silver nanoparticles were produced by mechanical milling and indirect hot extrusion. The milling products were obtained in a high energy SPEX ball mill, and then were compacted by uniaxial load and pressure-less sintered under argon atmosphere. Finally, the sintered product was hot extruded. Carbon coated silver nanoparticles were well distributed in the matrix of the extruded material. Tensile tests were carried out to corroborate the hypothesis that second phase particles, well dispersed in the matrix, improve the strength of the material. High resolution transmission electron microscopy was employed to locate and make sure that the silver nanoparticles were homogeneously and finely dispersed. Highlights: ► 7075 Al nanostructured composites can be produced by mechanical milling. ► Carbon coated silver nanoparticles are well dispersed into aluminum matrix. ► Ductile Ag–C NP's improve the mechanical properties of the 7075 Al-alloy. ► Ag–C NP's content has an important effect in the particle and crystallite size. ►Ag–C NP's keep their morphology after milling and conformation processes.

  3. Microstructure and mechanical properties of 7075 aluminum alloy nanostructured composites processed by mechanical milling and indirect hot extrusion

    Energy Technology Data Exchange (ETDEWEB)

    Flores-Campos, R., E-mail: ruben.flores@itesm.mx [Centro de Investigacion en Materiales Avanzados (CIMAV), Laboratorio Nacional de Nanotecnologia, Miguel de Cervantes No. 120, CP 31109, Chihuahua, Chih., Mexico (Mexico); Tecnologico de Monterrey Campus Saltillo, Departamento de Ingenieria, Prol. Juan de la Barrera No. 1241 Ote., Col. Cumbres, CP 25270, Saltillo, Coah., Mexico (Mexico); Estrada-Guel, I., E-mail: ivanovich.estrada@cimav.edu.mx [Centro de Investigacion en Materiales Avanzados (CIMAV), Laboratorio Nacional de Nanotecnologia, Miguel de Cervantes No. 120, CP 31109, Chihuahua, Chih., Mexico (Mexico); Miki-Yoshida, M., E-mail: mario.miki@cimav.edu.mx [Centro de Investigacion en Materiales Avanzados (CIMAV), Laboratorio Nacional de Nanotecnologia, Miguel de Cervantes No. 120, CP 31109, Chihuahua, Chih., Mexico (Mexico); Martinez-Sanchez, R., E-mail: roberto.martinez@cimav.edu.mx [Centro de Investigacion en Materiales Avanzados (CIMAV), Laboratorio Nacional de Nanotecnologia, Miguel de Cervantes No. 120, CP 31109, Chihuahua, Chih., Mexico (Mexico); Herrera-Ramirez, J.M., E-mail: martin.herrera@cimav.edu.mx [Centro de Investigacion en Materiales Avanzados (CIMAV), Laboratorio Nacional de Nanotecnologia, Miguel de Cervantes No. 120, CP 31109, Chihuahua, Chih., Mexico (Mexico)

    2012-01-15

    Nanostructured composites of 7075 aluminum alloy and carbon coated silver nanoparticles were produced by mechanical milling and indirect hot extrusion. The milling products were obtained in a high energy SPEX ball mill, and then were compacted by uniaxial load and pressure-less sintered under argon atmosphere. Finally, the sintered product was hot extruded. Carbon coated silver nanoparticles were well distributed in the matrix of the extruded material. Tensile tests were carried out to corroborate the hypothesis that second phase particles, well dispersed in the matrix, improve the strength of the material. High resolution transmission electron microscopy was employed to locate and make sure that the silver nanoparticles were homogeneously and finely dispersed. Highlights: Black-Right-Pointing-Pointer 7075 Al nanostructured composites can be produced by mechanical milling. Black-Right-Pointing-Pointer Carbon coated silver nanoparticles are well dispersed into aluminum matrix. Black-Right-Pointing-Pointer Ductile Ag-C NP's improve the mechanical properties of the 7075 Al-alloy. Black-Right-Pointing-Pointer Ag-C NP's content has an important effect in the particle and crystallite size. Black-Right-Pointing-Pointer Ag-C NP's keep their morphology after milling and conformation processes.

  4. Preparation of TiFe based alloys melted by CaO crucible and its hydrogen storage properties

    Energy Technology Data Exchange (ETDEWEB)

    Li, Chong-he, E-mail: chli@staff.shu.edu.cn [Shanghai Key Laboratory of Modern Metallurgy and Materials Processing, Shanghai University, Shanghai 200072 (China); Shanghai Special Casting Engineering Technology Research Center, Shanghai 201605 (China); He, Jin; Zhang, Zhao; Yang, Bo; Leng, Hai-yan [Shanghai Key Laboratory of Modern Metallurgy and Materials Processing, Shanghai University, Shanghai 200072 (China); Lu, Xiong-gang, E-mail: luxg@staff.shu.edu.cn [Shanghai Key Laboratory of Modern Metallurgy and Materials Processing, Shanghai University, Shanghai 200072 (China); Shanghai Special Casting Engineering Technology Research Center, Shanghai 201605 (China); Li, Zhi-lin; Wu, Zhu [Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China); Wang, Hong-bin [Shanghai Key Laboratory of Modern Metallurgy and Materials Processing, Shanghai University, Shanghai 200072 (China); Shanghai Special Casting Engineering Technology Research Center, Shanghai 201605 (China)

    2015-01-05

    Highlights: • The home-made CaO crucible was used to prepare the TiFe based alloys. • The compositions as well as the content of oxygen can be effectively controlled. • The microstructure of the alloy melted by CaO crucible is dendrite. • The samples performed a good hydrogen storage performance. • The CaO crucible may be the promising candidate for melting the TiFe based alloys. - Abstract: The carbon contamination of alloys prepared by the electro graphite crucible is impossible to avoid due to the inherit reaction between the melt and the crucible. In this study, the TiFe-based alloy is prepared by VIM process using CaO crucible as well as the electro graphite crucible. The samples are examined by means of Optical Microscopy (OM), Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD) and Energy Dispersive Spectrometer (EDS), and the PCT curves are also measured. It is resulted that, the oxygen content of alloys melted by CaO crucible is almost equal to the one melted by graphite crucible and without the carbon contamination, meanwhile the carbon content of alloys obtained by the electro graphite crucible is 1860 ppm, which exceeds the tolerance of the commercial alloy (1000 ppm). The microstructure of the alloy melted by CaO crucible is dendrite, while it is composed of the equiaxed crystal with the lamellar structure and the spherical TiC particles distributed along grain boundaries or within the grain when melted by the graphite crucible; the interfacial reaction of the electro graphite crucible with TiFe alloy melt is serious and the interaction layer is formed up to 200 μm in thickness, the carbon in TiFe-based alloys forms TiC. The hydrogen desorption plateau pressure of alloys melted by CaO crucible is (0.11–0.4) × 10{sup 5} Pa, and that by the graphite crucible is (0.6–1) × 10{sup 5} Pa. This may imply that the CaO crucible may be the promising candidate for melting the high performance TiFe based hydrogen storage alloys.

  5. Elastic properties of fcc Fe-Mn-X (X = Cr, Co, Ni, Cu) alloys studied by the combinatorial thin film approach and ab initio calculations.

    Science.gov (United States)

    Reeh, S; Kasprzak, M; Klusmann, C D; Stalf, F; Music, D; Ekholm, M; Abrikosov, I A; Schneider, J M

    2013-06-19

    The elastic properties of fcc Fe-Mn-X (X = Cr, Co, Ni, Cu) alloys with additions of up to 8 at.% X were studied by combinatorial thin film growth and characterization and by ab initio calculations using the disordered local moments (DLM) approach. The lattice parameter and Young's modulus values change only marginally with X. The calculations and experiments are in good agreement. We demonstrate that the elastic properties of transition metal alloyed Fe-Mn can be predicted by the DLM model.

  6. Microstructure and magnetic properties of Fe-Co-Nd-Y-B alloys obtained by suction casting method

    Institute of Scientific and Technical Information of China (English)

    J.Olszewski; J.Zbroszczyk; M.Hasiak; J.Kaleta; M.Nabia(l)ek; P.Bragiel; K.Sobczyk; W.Ciurzy(n)ska; J.(S)wierczek; A.(L)ukiewska

    2009-01-01

    The phase composition,magnetic properties i.e.coercivity and the magnetic polarization at room temperature for the bulk Fe67Co5Nd3Y6B19 and Fe64Co5Nd6Y6B19 alloys were studied.The bulk amorphous Fe67Co5Nd3Y6B19 alloy,inhomogeneous in the as-quenched state,crystallized after annealing at 948 K for 0.5 h and consisted of Nd2Fel4B-type,Fe2B and paramagnetic phases.The rapidly solidified Fe67Co5Nd3Y6B19 alloy contained the Nd2Fe14B-type and paramagnetic phases.The annealing of the bulk Fe67Co5Nd3Y6B19 alloy at 948 K for 0.5 h led to hard magnetic properties.However,the bulk Fe67Co5Nd3Y6B19 alloy exhibited good hard magnetic properties directly after preparation.

  7. COMPUTER NUMERICAL SIMULATION OF MECHANICAL PROPERTIES OF TUNGSTEN HEAVY ALLOYS

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    A microstructure model of tungsten heavy alloys has been developed. On the basis of the model and several assumptions, the macro-mechanical properties of 90 W heavy alloy under quasi-static tensile deformation and the effects of microstructural parameters (mechanical properties of the matrix phase and tungsten content) on them have been analyzed by computer numerical simulation. The mechanical properties of the alloy have been found to be dependent on the mechanical parameters of the matrix phase. As the elastic modulus and yield strength of the matrix phase increase, the tensile strength of the alloy increases, while the elongation decreases. If the mechanical parameters except the tensile strength of the matrix phase are constant, both the tensile strength and the elongation of the alloy increase linearly with the increase of tensile strength of the matrix phase. The properties of the alloy are very sensitive to the hardening modulus of the matrix phase. As the hardening modulus increases, both the tensile strength and the elongation of the alloy exponentially decrease. The elongation of the alloys monotonically decreases with the increase of tungsten content, while the decrease of tensile strength is not monotonic. When the tungsten content < 85 %, the strength of tungsten heavy alloys increases with the increase of tungsten content, while decreases when the tungsten content >85 %. The maximum of tensile strength of the alloys appears at the tungsten content of 85 %. The results showed that the binder phase with a higher strength and a lower hardening modulus is advantageous to obtaining an optimum combination of mechanical properties of tungsten heavy alloys.

  8. Estimation of thermal expansion properties of quasicrystalline alloys

    Institute of Scientific and Technical Information of China (English)

    齐育红; 张占平; 黑祖昆

    2004-01-01

    By investigating the thermal expansion properties of three quasicrystalline alloys Al65 Cu20 Cr15 quenched,Al65Cu20Cr15 cast and Al65Cu20Fe15 cast particles reinforced Al matrix composites from 25 ℃ to 500 ℃, the thermal expansion coefficients of three quasicrystalline alloys were theoretically estimated. The results show that the thermal expansion coefficients of the composites are much lower than that of pure Al, and the thermal expansion coefficients of the composites reinforced by Al-Cu-Cr quasicrystalline particles are lower than those of the composites reinforced by Al-Cu-Fe quasicrystalline particles. According to estimating, quasicrystalline alloys have negative thermal expansion coefficients, and the thermal expansion coefficients of Al-Cu-Cr quasicrystalline alloys are lower than those of Al-Cu-Fe quasicrystalline alloys. In the alloys, the more the qusicrystalline content, the lower the thermal expansion coefficient.

  9. Microstructure and mechanical properties relation in cold rolled Al 2024 alloy determined by X-ray line profile analysis

    International Nuclear Information System (INIS)

    Solution treated aluminum 2024 alloy sheets were subjected to rolling at room and cryogenic temperatures. Aging time and mechanical properties were evaluated by microhardness measurements and tensile test, respectively. Microstructural parameters were assessed by applying modified Williamson–Hall and modified Warren–Averbach methods to the X-ray diffraction patterns. Interestingly, the mechanical behavior of the different as-rolled and post-roll aged samples was in correlation with the sub-grain sizes and dislocation densities. The sub-grain sizes of the as-rolled samples were smaller than 40 nm, and the dislocation densities were larger than 7.7×1015 m−2, which is related to the high strength of the as-rolled samples. After aging treatment, the ductility of the rolled samples increased significantly, this was justified by the decline in the dislocation density

  10. Influence of yttrium on microstructure and properties of NieAl alloy coatings prepared by laser cladding

    Institute of Scientific and Technical Information of China (English)

    Cun-shan WANG

    2014-01-01

    NieAl alloy coatings with different Y additions are prepared on 45# medium steel by laser cladding. The influence of Y contents on the microstructure and properties of NieAl alloy coatings is investigated using X-ray diffraction, scanning electron microscopy, electron probe microanalyzer, Vickers hardness tester, friction wear testing machine, and thermal analyzer. The results show that the cladding layers are mainly composed of NiAl dendrites, and the dendrites are gradually refined with the increase in Y additions. The purification effect of Y can effectively prevent Al2O3 oxide from forming. However, when the atomic percent of Y addition exceeds 1.5%, the extra Y addition will react with O to form Y2O3 oxide, even to form Al5Y3O12 oxide, depending on the amount of Y added. The Y addition in a range of 1.5e3.5 at.%reduces the hardness and anti-attrition of cladding layer, but improves obviously its wear and oxidation resistances.

  11. Influence of yttrium on microstructure and properties of Ni–Al alloy coatings prepared by laser cladding

    Directory of Open Access Journals (Sweden)

    Cun-shan Wang

    2014-03-01

    Full Text Available Ni–Al alloy coatings with different Y additions are prepared on 45# medium steel by laser cladding. The influence of Y contents on the microstructure and properties of Ni–Al alloy coatings is investigated using X-ray diffraction, scanning electron microscopy, electron probe microanalyzer, Vickers hardness tester, friction wear testing machine, and thermal analyzer. The results show that the cladding layers are mainly composed of NiAl dendrites, and the dendrites are gradually refined with the increase in Y additions. The purification effect of Y can effectively prevent Al2O3 oxide from forming. However, when the atomic percent of Y addition exceeds 1.5%, the extra Y addition will react with O to form Y2O3 oxide, even to form Al5Y3O12 oxide, depending on the amount of Y added. The Y addition in a range of 1.5–3.5 at.% reduces the hardness and anti-attrition of cladding layer, but improves obviously its wear and oxidation resistances.

  12. Thermodynamic properties of average-atom interatomic potentials for alloys

    Science.gov (United States)

    Nöhring, Wolfram Georg; Curtin, William Arthur

    2016-05-01

    The atomistic mechanisms of deformation in multicomponent random alloys are challenging to model because of their extensive structural and compositional disorder. For embedded-atom-method interatomic potentials, a formal averaging procedure can generate an average-atom EAM potential and this average-atom potential has recently been shown to accurately predict many zero-temperature properties of the true random alloy. Here, the finite-temperature thermodynamic properties of the average-atom potential are investigated to determine if the average-atom potential can represent the true random alloy Helmholtz free energy as well as important finite-temperature properties. Using a thermodynamic integration approach, the average-atom system is found to have an entropy difference of at most 0.05 k B/atom relative to the true random alloy over a wide temperature range, as demonstrated on FeNiCr and Ni85Al15 model alloys. Lattice constants, and thus thermal expansion, and elastic constants are also well-predicted (within a few percent) by the average-atom potential over a wide temperature range. The largest differences between the average atom and true random alloy are found in the zero temperature properties, which reflect the role of local structural disorder in the true random alloy. Thus, the average-atom potential is a valuable strategy for modeling alloys at finite temperatures.

  13. Measurement of Thermodynamic Properties of Titanium Aluminum Alloys

    Science.gov (United States)

    Mehrotra, Gopal

    1995-01-01

    This final report is a summary of the work done by Professor Mehrotra at NASA Lewis Research Center. He has worked extensively on the measurement of thermodynamic properties of titanium aluminum alloys over the past six years.

  14. Fabrication of CoZn alloy nanowire arrays: Significant improvement in magnetic properties by annealing process

    Energy Technology Data Exchange (ETDEWEB)

    Koohbor, M. [Department of Physics, University of Kurdistan, Sanandaj (Iran, Islamic Republic of); Soltanian, S., E-mail: s.soltanian@gmail.com [Department of Physics, University of Kurdistan, Sanandaj (Iran, Islamic Republic of); Department of Electrical and Computer Engineering, University of British Columbia, Vancouver (Canada); Najafi, M. [Department of Physics, University of Kurdistan, Sanandaj (Iran, Islamic Republic of); Department of Physics, Hamadan University of Technology, Hamadan (Iran, Islamic Republic of); Servati, P. [Department of Electrical and Computer Engineering, University of British Columbia, Vancouver (Canada)

    2012-01-05

    Highlights: Black-Right-Pointing-Pointer Increasing the Zn concentration changes the structure of NWs from hcp to amorphous. Black-Right-Pointing-Pointer Increasing the Zn concentration significantly reduces the Hc value of NWs. Black-Right-Pointing-Pointer Magnetic properties of CoZn NWs can be significantly enhanced by appropriate annealing. Black-Right-Pointing-Pointer The pH of electrolyte has no significant effect on the properties of the NW arrays. Black-Right-Pointing-Pointer Deposition frequency has considerable effects on the magnetic properties of NWs. - Abstract: Highly ordered arrays of Co{sub 1-x}Zn{sub x} (0 {<=} x {<=} 0.74) nanowires (NWs) with diameters of {approx}35 nm and high length-to-diameter ratios (up to 150) were fabricated by co-electrodeposition of Co and Zn into pores of anodized aluminum oxide (AAO) templates. The Co and Zn contents of the NWs were adjusted by varying the ratio of Zn and Co ion concentrations in the electrolyte. The effect of the Zn content, electrodeposition conditions (frequency and pH) and annealing on the structural and magnetic properties (e.g., coercivity (Hc) and squareness (Sq)) of NW arrays were investigated using X-ray diffraction (XRD), scanning electron microscopy, electron diffraction, and alternating gradient force magnetometer (AGFM). XRD patterns reveal that an increase in the concentration of Zn ions of the electrolyte forces the hcp crystal structure of Co NWs to change into an amorphous phase, resulting in a significant reduction in Hc. It was found that the magnetic properties of NWs can be significantly improved by appropriate annealing process. The highest values for Hc (2050 Oe) and Sq (0.98) were obtained for NWs electrodeposited using 0.95/0.05 Co:Zn concentrations at 200 Hz and annealed at 575 Degree-Sign C. While the pH of electrolyte is found to have no significant effect on the structural and magnetic properties of the NW arrays, the electrodeposition frequency has considerable effects on

  15. HIGH CYCLE FATIGUE PROPERTIES OF NICKEL-BASE ALLOY 718

    Institute of Scientific and Technical Information of China (English)

    K.Kobayashi; K.Yamaguchi; M.Hayakawa; M.Kimura

    2004-01-01

    The fatigue properties of nickel-base Alloy 718 with fine- and grain-coarse grains were investigated. In the fine-grain alloy, the fatigue strength normalized by the tensile strengtn was 0.51 at 107 cycles. In contrast, the fatigue strength of the coarse-grain alloy was 0.32 at the same cycles, although the fatigue strengths in the range from 103to 105 cycles are the same for both alloys. The fracture appearances fatigued at around 106 cycles showed internal fractures originating from the flat facets of austenite grains for both alloys. The difference in fatigue strength at 107 cycles between the fine- and coarse-grain alloys could be explained in terms of the sizes of the facets from which the fractures originated.

  16. Microstructures and properties of Cr-Cu/W-Cu bi-layer composite coatings prepared by mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jiaping; Feng, Xiaomei; Shen, Yifu; Chen, Cheng; Duan, Cuiyuan [Nanjing Univ. of Aeronautics and Astronautics (China). Dept. of Materials Science and Technology

    2016-06-15

    Cr-Cu/W-Cu bi-layer coatings with composite structures were fabricated by means of mechanical alloying. The Cr-Cu layer and the W-Cu layer were deposited successively and the as-synthesized bi-layer coating was made up of an inner Cr-Cu layer and an outer W-Cu layer. Microstructures, chemical and phase compositions of the as-prepared coatings were characterized. The results indicated that the bonding between the inner coating and the substrate was improved with the increase of Cu in the raw powder. The annealing treatment of the inner Cr-Cu layer was beneficial to the bonding between the inner Cr-Cu coating and the outer W-Cu coating layer. Mechanical properties such as microhardness, friction and wear resistance were tested. The as-synthesized coating could effectively improve the hardness and wear resistance of the Cu substrate.

  17. Characterization and properties of ZnO1-xSx alloy films fabricated by radio-frequency magnetron sputtering

    International Nuclear Information System (INIS)

    A series of ZnO1-xSx alloy films (0 ≤ x ≤ 1) were grown on quartz substrates by radio-frequency (rf) magnetron sputtering of ZnS ceramic target, using oxygen and argon as working gas. X-ray diffraction measurement shows that the ZnO1-xSx films have wurtzite structure with (0 0 2) preferential orientation in O-rich side (0 ≤ x ≤ 0.23) and zinc blende structure with (1 1 1) preferential orientation in S-rich side (0.77 ≤ x ≤ 1). However, when the S content is in the range of 0.23 1-xSx film consists of two phases of wurtzite and zinc blende or amorphous ZnO1-xSx phase. The band gap energy of the films shows non-linear dependence on the S content, with an optical bowing parameter of about 2.9 eV. The photoluminescence (PL) measurement reveals that the PL spectrum of the wurtzite ZnO1-xSx is dominated by visible band and its PL intensity and intensity ratio of UV to visible band decrease greatly compared with undoped ZnO. All as-grown ZnO1-xSx films behave insulating, but show n-type conductivity for w-ZnO1-xSx and maintain insulating properties for β-ZnO1-xSx after annealed. Mechanisms of effects of S on optical and electrical properties of the ZnO1-xSx alloy are discussed in the present work.

  18. Microstructure and mechanical properties of biomedical alloys produced by Rapid Manufacturing techniques

    OpenAIRE

    Facchini, Luca

    2010-01-01

    Rapid Manufacturing (RM) technologies as Electron Beam Melting (EBM) and Selective Laser Melting (SLM) are able to produce fully dense parts from pre-alloyed powders in a layer-wise way. Moreover, they are able to create tailored surfaces with interconnected porosity. Applied to biomedical prostheses, such porosity can favour cell adhesion and osteointegration. The most important intrinsic characteristic of RM techniques is the large undercooling the parts undergo during the process. This ...

  19. Microstructural, phase transformation and magnetic properties of Ni-Mn-Ga alloy fabricated by spark plasma sintering

    Institute of Scientific and Technical Information of China (English)

    Tian Xiao-Hua; Sui Jie-He; Zhang Xin; Feng Xue; Cai Wei

    2011-01-01

    The microstructural, phase transformation and magnetic properties of Ni-Mn-Ga alloy fabricated using the spark plasma sintering method have been investigated. The results show that both the as-sintered and annealed sintered specimens exhibit typical martensitic transformation behaviours. The martensite of the sintered specimen after annealing exhibits a ferromagnetic nature. Moreover, study of the fracture surface indicates that the transgranular fracture contributes to the higher ductility of sintered Ni-Mn-Ga alloy. In addition, the transformation strain in sintered Ni-Mn-Gaalloy is studied for the first time.

  20. Microstructure and Mechanical Properties of MWCNTs Reinforced A356 Aluminum Alloys Cast Nanocomposites Fabricated by Using a Combination of Rheocasting and Squeeze Casting Techniques

    Directory of Open Access Journals (Sweden)

    Abou Bakr Elshalakany

    2014-01-01

    Full Text Available A356 hypoeutectic aluminum-silicon alloys matrix composites reinforced by different contents of multiwalled carbon nanotubes (MWCNTs were fabricated using a combination of rheocasting and squeeze casting techniques. A novel approach by adding MWCNTs into A356 aluminum alloy matrix with CNTs has been performed. This method is significant in debundling and preventing flotation of the CNTs within the molten alloy. The microstructures of nanocomposites and the interface between the aluminum alloy matrix and the MWCNTs were examined by using an optical microscopy (OM and scanning electron microscopy (SEM equipped with an energy dispersive X-ray analysis (EDX. This method remarkably facilitated a uniform dispersion of nanotubes within A356 aluminum alloy matrix as well as a refinement of grain size. In addition, the effects of weight fraction (0.5, 1.0, 1.5, 2.0, and 2.5 wt% of the CNT-blended matrix on mechanical properties were evaluated. The results have indicated that a significant improvement in ultimate tensile strength and elongation percentage of nanocomposite occurred at the optimal amount of 1.5 wt% MWCNTs which represents an increase in their values by a ratio of about 50% and 280%, respectively, compared to their corresponding values of monolithic alloy. Hardness of the samples was also significantly increased by the addition of CNTs.

  1. Investigation of surface properties of high temperature nitrided titanium alloys

    OpenAIRE

    Koyuncu, E.; F. Kahraman; Ö. Karadeniz

    2009-01-01

    Purpose: The purpose of paper is to investigate surface properties of high temperature nitrided titanium alloys.Design/methodology/approach: In this study, surface modification of Ti6Al4V titanium alloy was made at various temperatures by plasma nitriding process. Plasma nitriding treatment was performed in 80% N2-20% H2 gas mixture, for treatment times of 2-15 h at the temperatures of 700-1000°C. Surface properties of plasma nitrided Ti6Al4V alloy were examined by metallographic inspection, ...

  2. Effect of Specific Energy Input on Microstructure and Mechanical Properties of Nickel-Base Intermetallic Alloy Deposited by Laser Cladding

    Science.gov (United States)

    Awasthi, Reena; Kumar, Santosh; Chandra, Kamlesh; Vishwanadh, B.; Kishore, R.; Viswanadham, C. S.; Srivastava, D.; Dey, G. K.

    2012-12-01

    This article describes the microstructural features and mechanical properties of nickel-base intermetallic alloy laser-clad layers on stainless steel-316 L substrate, with specific attention on the effect of laser-specific energy input (defined as the energy required per unit of the clad mass, kJ/g) on the microstructure and properties of the clad layer, keeping the other laser-cladding parameters same. Defect-free clad layers were observed, in which various solidified zones could be distinguished: planar crystallization near the substrate/clad interface, followed by cellular and dendritic morphology towards the surface of the clad layer. The clad layers were characterized by the presence of a hard molybdenum-rich hexagonal close-packed (hcp) intermetallic Laves phase dispersed in a relatively softer face-centered cubic (fcc) gamma solid solution or a fine lamellar eutectic phase mixture of an intermetallic Laves phase and gamma solid solution. The microstructure and properties of the clad layers showed a strong correlation with the laser-specific energy input. As the specific energy input increased, the dilution of the clad layer increased and the microstructure changed from a hypereutectic structure (with a compact dispersion of characteristic primary hard intermetallic Laves phase in eutectic phase mixture) to near eutectic or hypoeutectic structure (with reduced fraction of primary hard intermetallic Laves phase) with a corresponding decrease in the clad layer hardness.

  3. Properties of electrodeposited amorphous Fe-Ni-W alloy deposits

    Institute of Scientific and Technical Information of China (English)

    HE Feng-jiao; WANG Miao; LU Xin

    2006-01-01

    A new technique of electroplating amorphous Fe-Ni-W alloy deposits was proposed. The structure and morphology of Fe-Ni-W alloy deposit were detected by XRD and SEM. The friction and wear behavior of Fe-Ni-W alloy deposit were studied and compared with that of chromium deposit. The corrosion properties against 5% sodium chloride, 5% sulfuric acid and 5% sodium hydroxide were also discussed. The experimental results indicate that Fe-Ni-W alloy deposits have superior properties against wear than hard chromium deposits under dry sliding condition. Under oil sliding condition, except their better wear resistance, the deposits can protect their counterparts against wear. The deposits plated on brass and AISI 1045 steel show good behavior against corrosion of 5% sodium chloride, 5% sulfuric acid and 5% sodium hydroxide. The bath of electroplating amorphous Fe-Ni-W alloy deposits is environmentally friendly and would find widely use in industry.

  4. Mechanical properties of Cu sbnd Cr sbnd Zr alloy and SS316 joints fabricated by friction welding method

    Science.gov (United States)

    Tsuchiya, Kunihiko; Kawamura, Hiroshi

    1996-10-01

    Copper alloys with high-strength and high-conductivity are being considered for several magnetic fusion energy applications such as the first wall in high power-density devices, resistive magnetic coils, and high-heat flux components. For example, the stainless steel is a structural material while Cu-alloy acts as a heat sink material for the surface heat flux in the first wall. Therefore, development of reliable joints between Cu-alloys and stainless steel (SS316) is required. In the present work, joining tests on Cu—1%Cr—1%Zr/SS316 by friction welding were performed, and optimum fabricating conditions of the Cu-alloy/SS316 joint were determined. Additionally, the characteristics of tensile strength, hardness, metallographical observation and SEM/EPMA analyses on Cu—1%Cr—1%Zr/SS316 fabricated by friction welding were evaluated.

  5. Rheo-Cast Microstructure and Mechanical Properties of AM60 Alloy Produced by Self-Inoculation Rheo-Diecasting Process

    Directory of Open Access Journals (Sweden)

    Bo Xing

    2016-03-01

    Full Text Available Rheo-forming is becoming the choice for production of high quality parts with diminished defects and fine integrity. In this paper, the novel self-inoculation rheo-diecasting (SIRD process, in which semisolid slurry is produced by mixing two precursory solid and liquid alloys and subsequently pouring them through a multi-stream fluid director, has been proposed. Microstructural characteristics of AM60 alloy slurry and the microstructure and mechanical properties of rheo-diecasting AM60 samples were investigated. Quenching experiments reveal that the slurry microstructure of AM60 was well refined to irregular α-Mg particles with the average size of approximately 20–40 μm after pouring with the self-inoculation process, and these particles were evolved to globular and coarse morphology while continuously keeping in semisolid state. After rheo-diecasting, the microstructure of the sample was dominated by fine primary α-Mg globules accompanied with tiny secondary α-Mg particles while the sample from conventional liquid die casting was characterized by developed dendrite and porosity. Microscopic analysis indicates that there are three stages of remaining liquid solidification in die cavity in SIRD: α-Mg nucleation and growth on primary α-Mg surface, α-Mg nucleated independently in liquid, and, finally, formation of skeleton devoiced eutectic. Due to diminished porosity and hot tearing, tensile strength and elongation of SIRD samples were increased by 12.9% and 35.3%, respectively, compared to a conventional liquid die casting sample.

  6. Structure changes and mechanical properties of laser alloyed magnesium cast alloys

    Directory of Open Access Journals (Sweden)

    W. Kwaśny

    2009-02-01

    Full Text Available Purpose: The aim of this work was to investigate structure and mechanical properties of the MCMgAl12Zn1 casting magnesium alloys after laser treatment. The laser treatment was carried out using a high power diode laser (HPDL.Design/methodology/approach: The laser processing of TiC, WC, SiC particles in MCMgAl12Zn1 and the resulted microstructures and properties are discussed in this paper. The resulting microstructure in the modified surface layer was examined. Phase composition was determined by the X-ray diffraction method using XPert device. The measurements of hardness after laser melt injection was also studied.Findings: Structure of the solidyifying material after laser alloying is characteristic with occurrences of areas with the diversified morphology, dependent on solidification rate of the magnesium alloys, is characteristic of structure of the solidified material after laser alloying. The MCMgAl12Zn1 casting magnesium alloys after laser alloying demonstrate similar hardness tests results, in reference to hardness of the alloys before their laser treatment.Research limitations/implications: In this research three powders (titanium carbide, tungsten carbide and silicon carbide were used to reinforcing the surface of the MCMgAl12Zn1 casting magnesium alloys.Practical implications: High power diode laser can be used as an economical substitute for CO2 and Nd:YAG lasers to modify the surface magnesium alloy by feeding the carbide particles.Originality/value: The originality of this work is applying of High Power Diode Laser for laser treatment of cast magnesium alloy consisting in fusion penetration of the hard particles of titanium, tungsten, and silicon carbides into the remelted surface layer of the alloy.

  7. Microstructure and mechanical properties of ZE10 magnesium alloy prepared by equal channel angular pressing

    Institute of Scientific and Technical Information of China (English)

    Ying Liu; Wei Li; Yuan-yuan Li

    2009-01-01

    ZE10 magnesium alloy was subjected to equal-channel angular pressing (ECAP) up to 12 passes in a die with an angle of 120° between the two channels at 250-300°C. An inhomogeneous microstructure of bimodal grains including fine grains of 1-2 μm as well as coarse grains of about 20 °tm was obtained after the initial 1-4 ECAP passes. The grain size became increasingly homoge-neous with further ECAP processing and the grains were significantly refined to 1-2 μm after 8 passes and further refined to 0.5-1 μm after 12 passes. The alloy's yield strength changed slightly but the ductility improved greatly initially up to 4-6 passes corre-sponding to the bimodal grain microstrueture. And after the subsequent pressing of more than 8 passes, the tensile strength including yield strength improved while the elongation decreased gradually.

  8. Structure and properties of nitrided surface layer produced on NiTi shape memory alloy by low temperature plasma nitriding

    Science.gov (United States)

    Czarnowska, Elżbieta; Borowski, Tomasz; Sowińska, Agnieszka; Lelątko, Józef; Oleksiak, Justyna; Kamiński, Janusz; Tarnowski, Michał; Wierzchoń, Tadeusz

    2015-04-01

    NiTi shape memory alloys are used for bone and cardiological implants. However, on account of the metallosis effect, i.e. the release of the alloy elements into surrounding tissues, they are subjected to various surface treatment processes in order to improve their corrosion resistance and biocompatibility without influencing the required shape memory properties. In this paper, the microstructure, topography and morphology of TiN surface layer on NiTi alloy, and corrosion resistance, both before and after nitriding in low-temperature plasma at 290 °C, are presented. Examinations with the use of the potentiodynamic and electrochemical impedance spectroscopy methods were carried out and show an increase of corrosion resistance in Ringer's solution after glow-discharge nitriding. This surface titanium nitride layer also improved the adhesion of platelets and the proliferation of osteoblasts, which was investigated in in vitro experiments with human cells. Experimental data revealed that nitriding NiTi shape memory alloy under low-temperature plasma improves its properties for bone implant applications.

  9. Microstructures and mechanical properties of Co-29Cr-6Mo alloy fabricated by selective laser melting process for dental applications.

    Science.gov (United States)

    Takaichi, Atsushi; Suyalatu; Nakamoto, Takayuki; Joko, Natsuka; Nomura, Naoyuki; Tsutsumi, Yusuke; Migita, Satoshi; Doi, Hisashi; Kurosu, Shingo; Chiba, Akihiko; Wakabayashi, Noriyuki; Igarashi, Yoshimasa; Hanawa, Takao

    2013-05-01

    The selective laser melting (SLM) process was applied to a Co-29Cr-6Mo alloy, and its microstructure, mechanical properties, and metal elution were investigated to determine whether the fabrication process is suitable for dental applications. The microstructure was evaluated using scanning electron microscopy with energy-dispersed X-ray spectroscopy (SEM-EDS), X-ray diffractometry (XRD), and electron back-scattered diffraction pattern analysis. The mechanical properties were evaluated using a tensile test. Dense builds were obtained when the input energy of the laser scan was higher than 400 J mm⁻³, whereas porous builds were formed when the input energy was lower than 150 J mm⁻³. The microstructure obtained was unique with fine cellular dendrites in the elongated grains parallel to the building direction. The γ phase was dominant in the build and its preferential orientation was confirmed along the building direction, which was clearly observed for the builds fabricated at lower input energy. Although the mechanical anisotropy was confirmed in the SLM builds due to the unique microstructure, the yield strength, UTS, and elongation were higher than those of the as-cast alloy and satisfied the type 5 criteria in ISO22764. Metal elution from the SLM build was smaller than that of the as-cast alloy, and thus, the SLM process for the Co-29Cr-6Mo alloy is a promising candidate for fabricating dental devices.

  10. Microstructures and mechanical properties of Co-29Cr-6Mo alloy fabricated by selective laser melting process for dental applications.

    Science.gov (United States)

    Takaichi, Atsushi; Suyalatu; Nakamoto, Takayuki; Joko, Natsuka; Nomura, Naoyuki; Tsutsumi, Yusuke; Migita, Satoshi; Doi, Hisashi; Kurosu, Shingo; Chiba, Akihiko; Wakabayashi, Noriyuki; Igarashi, Yoshimasa; Hanawa, Takao

    2013-05-01

    The selective laser melting (SLM) process was applied to a Co-29Cr-6Mo alloy, and its microstructure, mechanical properties, and metal elution were investigated to determine whether the fabrication process is suitable for dental applications. The microstructure was evaluated using scanning electron microscopy with energy-dispersed X-ray spectroscopy (SEM-EDS), X-ray diffractometry (XRD), and electron back-scattered diffraction pattern analysis. The mechanical properties were evaluated using a tensile test. Dense builds were obtained when the input energy of the laser scan was higher than 400 J mm⁻³, whereas porous builds were formed when the input energy was lower than 150 J mm⁻³. The microstructure obtained was unique with fine cellular dendrites in the elongated grains parallel to the building direction. The γ phase was dominant in the build and its preferential orientation was confirmed along the building direction, which was clearly observed for the builds fabricated at lower input energy. Although the mechanical anisotropy was confirmed in the SLM builds due to the unique microstructure, the yield strength, UTS, and elongation were higher than those of the as-cast alloy and satisfied the type 5 criteria in ISO22764. Metal elution from the SLM build was smaller than that of the as-cast alloy, and thus, the SLM process for the Co-29Cr-6Mo alloy is a promising candidate for fabricating dental devices. PMID:23500549

  11. Effects of Fe content on the microstructure and properties of CuNi10FeMn1 alloy tubes fabricated by HCCM horizontal continuous casting

    Science.gov (United States)

    Jiang, Yan-bin; Xu, Jun; Liu, Xin-hua; Xie, Jian-xin

    2016-04-01

    Heating-cooling combined mold (HCCM) horizontal continuous casting technology developed by our research group was used to produce high axial columnar-grained CuNi10FeMn1 alloy tubes with different Fe contents. The effects of Fe content (1.08wt%-2.01wt%) on the microstructure, segregation, and flushing corrosion resistance in simulated flowing seawater as well as the mechanical properties of the alloy tubes were investigated. The results show that when the Fe content is increased from 1.08wt% to 2.01wt%, the segregation degree of Ni and Fe elements increases, and the segregation coefficient of Ni and Fe elements falls from 0.92 to 0.70 and from 0.92 to 0.63, respectively. With increasing Fe content, the corrosion rate of the alloy decreases initially and then increases. When the Fe content is 1.83wt%, the corrosion rate approaches the minimum and dense, less-defect corrosion films, which contain rich Ni and Fe elements, form on the surface of the alloy; these films effectively protect the α-matrix and reduce the corrosion rate. When the Fe content is increased from 1.08wt% to 2.01wt%, the tensile strength of the alloy tube increases from 204 MPa to 236 MPa, while the elongation to failure changes slightly about 46%, indicating the excellent workability of the CuNi10FeMn1 alloy tubes.

  12. Plasma surface alloying of titanium alloy for enhancing burn-resistant property

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ping-ze; XU Zhong; ZHANG Gao-hui; HE Zhi-yong; YAO Zheng-jun

    2006-01-01

    Conventional titanium alloy may be ignited and burnt under high temperature, high pressure and high gas flow velocity condition. In order to avoid this problem, burn-resistant alloying layers were made on the surface of Ti-6Al-4V and Ti-6.5Al-0.3Mo-1.5Zr-0.25Si titanium alloys by using double glow plasma surface alloying technology (DG Technology). Two typical burn-resistant layers Ti-Cr and Ti-Mo were made by DG plasma chromizing and DG plasma molybdenizing, respectively. Burn-resistant properties were tested by layer ignition method using 2 kW laser machine. Ignition experiments result reveals that the ignition temperature of alloyed layer with Mo and Cr concentration above 10% is about 200℃ higher than ignition temperature of Ti-6Al-4V substrate.

  13. The Microstructure-Processing-Property Relationships in an Al Matrix Composite System Reinforced by Al-Cu-Fe Alloy Particles

    Energy Technology Data Exchange (ETDEWEB)

    Fei Tang

    2004-12-19

    Metal matrix composites (MMC), especially Al matrix composites, received a lot of attention during many years of research because of their promise for the development of automotive and aerospace materials with improved properties and performance, such as lighter weight and better structural properties, improved thermal conductivity and wear resistance. In order to make the MMC materials more viable in various applications, current research efforts on the MMCs should continue to focus on two important aspects, including improving the properties of MMCs and finding more economical techniques to produce MMCs. Solid state vacuum sintering was studied in tap densified Al powder and in hot quasi-isostatically forged samples composed of commercial inert gas atomized or high purity Al powder, generated by a gas atomization reaction synthesis (GARS) technique. The GARS process results in spherical Al powder with a far thinner surface oxide. The overall results indicated the enhanced ability of GARS-processed Al and Al alloy powders for solid state sintering, which may lead to simplification of current Al powder consolidation processing methods. Elemental Al-based composites reinforced with spherical Al-Cu-Fe alloy powders were produced by quasi-isostatic forging and vacuum hot pressing (VHP) consolidation methods. Microstructures and tensile properties of AYAl-Cu-Fe composites were characterized. It was proved that spherical Al-Cu-Fe alloy powders can serve as an effective reinforcement particulate for elemental Al-based composites, because of their high hardness and a preferred type of matrix/reinforcement interfacial bonding, with reduced strain concentration around the particles. Ultimate tensile strength and yield strength of the composites were increased over the corresponding Al matrix values, far beyond typical observations. This remarkable strengthening was achieved without precipitation hardening and without severe strain hardening during consolidation because of

  14. Energy investigations on the mechanical properties of magnesium alloyed by X = C, B, N, O and vacancy

    KAUST Repository

    Wu, Xiaozhi

    2013-10-25

    The generalized stacking fault (GSF) energies and surface energies of magnesium and its alloys with alloying atoms X = C, B, N, O and vacancy have been investigated using the first-principles methods. It is found that the predominant reducing effects of the alloying atoms and vacancy on the stacking fault energy are resulted from the position of them in the 1st layer near the slip plane. The stacking fault energies are nearly the same as the pure magnesium while the alloying atoms and vacancy are placed in the 2nd, 3rd, 4th, 5th and 6th layers. It has been shown that O strongly reduces the GSF energy of Mg. The alloying atoms C, B and N increase the surface energy, but O and vacancy reduce the surface energy of Mg. The ductilities of Mg and Mg alloys have been discussed based on the Rice criterion by using the ratio between surface energy and unstable stacking fault energy. © 2013 Higher Education Press and Springer-Verlag Berlin Heidelberg.

  15. Microstructure, mechanical properties, bio-corrosion properties and antibacterial properties of Ti-Ag sintered alloys.

    Science.gov (United States)

    Chen, Mian; Zhang, Erlin; Zhang, Lan

    2016-05-01

    In this research, Ag element was selected as an antibacterial agent to develop an antibacterial Ti-Ag alloy by a powder metallurgy. The microstructure, phase constitution, mechanical properties, corrosion resistance and antibacterial properties of the Ti-Ag sintered alloys have been systematically studied by X-ray diffraction (XRD), scanning electron microscope (SEM), compressive test, electrochemical measurements and antibacterial test. The effects of the Ag powder size and the Ag content on the antibacterial property and mechanical property as well as the anticorrosion property have been investigated. The microstructure results have shown that Ti-Ag phase, residual pure Ag and Ti were the mainly phases in Ti-Ag(S75) sintered alloy while Ti2Ag was synthesized in Ti-Ag(S10) sintered alloy. The mechanical test indicated that Ti-Ag sintered alloy showed a much higher hardness and the compressive yield strength than cp-Ti but the mechanical properties were slightly reduced with the increase of Ag content. Electrochemical results showed that Ag powder size had a significant effect on the corrosion resistance of Ti-Ag sintered alloy. Ag content increased the corrosion resistance in a dose dependent way under a homogeneous microstructure. Antibacterial tests have demonstrated that antibacterial Ti-Ag alloy was successfully prepared. It was also shown that the Ag powder particle size and the Ag content influenced the antibacterial activity seriously. The reduction in the Ag powder size was benefit to the improvement in the antibacterial property and the Ag content has to be at least 3wt.% in order to obtain a strong and stable antibacterial activity against Staphylococcus aureus bacteria. The bacterial mechanism was thought to be related to the Ti2Ag and its distribution.

  16. Microstructure, mechanical properties, bio-corrosion properties and antibacterial properties of Ti-Ag sintered alloys.

    Science.gov (United States)

    Chen, Mian; Zhang, Erlin; Zhang, Lan

    2016-05-01

    In this research, Ag element was selected as an antibacterial agent to develop an antibacterial Ti-Ag alloy by a powder metallurgy. The microstructure, phase constitution, mechanical properties, corrosion resistance and antibacterial properties of the Ti-Ag sintered alloys have been systematically studied by X-ray diffraction (XRD), scanning electron microscope (SEM), compressive test, electrochemical measurements and antibacterial test. The effects of the Ag powder size and the Ag content on the antibacterial property and mechanical property as well as the anticorrosion property have been investigated. The microstructure results have shown that Ti-Ag phase, residual pure Ag and Ti were the mainly phases in Ti-Ag(S75) sintered alloy while Ti2Ag was synthesized in Ti-Ag(S10) sintered alloy. The mechanical test indicated that Ti-Ag sintered alloy showed a much higher hardness and the compressive yield strength than cp-Ti but the mechanical properties were slightly reduced with the increase of Ag content. Electrochemical results showed that Ag powder size had a significant effect on the corrosion resistance of Ti-Ag sintered alloy. Ag content increased the corrosion resistance in a dose dependent way under a homogeneous microstructure. Antibacterial tests have demonstrated that antibacterial Ti-Ag alloy was successfully prepared. It was also shown that the Ag powder particle size and the Ag content influenced the antibacterial activity seriously. The reduction in the Ag powder size was benefit to the improvement in the antibacterial property and the Ag content has to be at least 3wt.% in order to obtain a strong and stable antibacterial activity against Staphylococcus aureus bacteria. The bacterial mechanism was thought to be related to the Ti2Ag and its distribution. PMID:26952433

  17. Microstructure and some mechanical properties of fly ash particulate reinforced AA6061 aluminum alloy composites prepared by compocasting

    International Nuclear Information System (INIS)

    Highlights: ► Fabrication of AA6061/fly ash AMC by compocasting method. ► Incorporation of fly ash particles into the semi solid aluminum melt. ► No interfacial reaction between the aluminum matrix and fly ash particle. ► Uniform distribution of fly ash particles having clear interface and good bonding. ► Fly ash particles enhanced the mechanical properties of the AMC. - Abstract: Fly ash has gathered widespread attention as a potential reinforcement for aluminum matrix composites (AMCs) to enhance the properties and reduce the cost of production. Aluminum alloy AA6061 reinforced with various amounts (0, 4, 8 and 12 wt.%) of fly ash particles were prepared by compocasting method. Fly ash particles were incorporated into the semi solid aluminum melt. X-ray diffraction patterns of the prepared AMCs revealed the presence of fly ash particles without the formation of any other intermetallic compounds. The microstructures of the AMCs were analyzed using scanning electron microscopy. The AMCs were characterized with the homogeneous dispersion of fly ash particles having clear interface and good bonding to the aluminum matrix. The incorporation of fly ash particles improved the microhardness and ultimate tensile strength (UTS) of the AMCs

  18. Investigation of surface properties of high temperature nitrided titanium alloys

    Directory of Open Access Journals (Sweden)

    E. Koyuncu

    2009-12-01

    Full Text Available Purpose: The purpose of paper is to investigate surface properties of high temperature nitrided titanium alloys.Design/methodology/approach: In this study, surface modification of Ti6Al4V titanium alloy was made at various temperatures by plasma nitriding process. Plasma nitriding treatment was performed in 80% N2-20% H2 gas mixture, for treatment times of 2-15 h at the temperatures of 700-1000°C. Surface properties of plasma nitrided Ti6Al4V alloy were examined by metallographic inspection, X-Ray diffraction and Vickers hardness.Findings: Two layers were determined by optic inspection on the samples that were called the compound and diffusion layers. Compound layer contain TiN and Ti2N nitrides, XRD results support in this formations. Maximum hardness was obtained at 10h treatment time and 1000°C treatment temperature. Micro hardness tests showed that hardness properties of the nitrided samples depend on treatment time and temperature.Practical implications: Titanium and its alloys have very attractive properties for many industries. But using of titanium and its alloys is of very low in mechanical engineering applications because of poor tribological properties.Originality/value: The nitriding of titanium alloy surfaces using plasma processes has already reached the industrial application stage in the biomedical field.

  19. Physical preparation and optical properties of CuSbS2 nanocrystals by mechanical alloying process

    Science.gov (United States)

    Zhang, Huihui; Xu, Qishu; Tan, Guolong

    2016-09-01

    CuSbS2 nanocrystals have been synthesized through mechanical alloying Cu, Sb and S elemental powders for 40 hs. The optical spectrum of as-milled CuSbS2 nano-powders demonstrates a direct gap of 1.35 eV and an indirect gap of 0.36 eV, which are similar to that of silicon and reveals the evidence for the indirect semiconductor characterization of CuSbS2. Afterwards, CuSbS2 nanocrystals were capped with trioctylphosphine oxide/trioctylphosphine/pyridine (TOPO/TOP). There appear four sharp absorption peaks within the region of 315 to 355 nm for the dispersion solution containing the capped nanocrystals. The multiple peaks are proposed to be originating from the energy level splitting of 1S electronic state into four discrete sub-levels, where electrons were excited into the conduction band and thus four exciton absorption peaks were produced.

  20. The effect of mechanical alloying on microstructure and mechanical properties of MoSi{sub 2} prepared by spark plasma sintering

    Energy Technology Data Exchange (ETDEWEB)

    Kermani, Milad, E-mail: miladkermani.mk@gmail.com; Razavi, Mansour; Rahimipour, Mohammad Reza; Zakeri, Mohammad

    2014-04-01

    Highlights: • Powders of Mo and Si according to MoSi{sub 2} stoichiometry were mechanically alloyed. • The as milled powder mixture was sintered using spark plasma sintering. • We investigated the microstructure and mechanical properties of samples. - Abstract: In this research the effect of mechanical alloying on the in situ synthesis–sintering behavior and mechanical properties of MoSi{sub 2} has been investigated. The Mo and Si powders according to MoSi{sub 2} stoichiometric composition were mechanically alloyed at different times. Then, the powders were subjected to spark plasma sintering process for preparing monolithic MoSi{sub 2}. X-ray diffraction pattern of the sintered samples showed that by increasing the mechanical alloying time, Mo{sub 5}Si{sub 3} has been formed. It seems that the formation of Mo{sub 5}Si{sub 3} is due to the effect of mechanical alloying on microstructure and thermodynamic condition of the reaction.

  1. Hydrogen sorption properties of Mg-20wt.%Fe 23 Y8 composite prepared by reactive mechanical alloying

    Institute of Scientific and Technical Information of China (English)

    LI Zhinian; LIU Xiaopeng; HUANG Zuo; JIANG Lijun; WANG Shumao

    2006-01-01

    Mg-20wt.% Fe23Y8 composite was successfully prepared by reactive mechanical alloying (RMA). X-ray diffraction (XRD) measurement shows that the main phases of composite are MgH2 and Mg2FeH6. The composite exhibits excellent hydrogen abs/desorption properties and can absorb 4.36wt.% and 5.72wt.% hydrogen at 473 and 573 K in 10 min under 3.0 Mpa hydrogen pressure, respectively. The composite can desorb 5.27wt.% hydrogen at 573 K in 30 min under 0.02 Mpa hydrogen pressure. Compared with the pure MgH2, the hydrogen desorption temperature of Mg-20wt.% Fe23Y8 composite is decreased about 40 ℃. It is supposed that both the catalyst effect of Fe-Y distributed in Mg substrate and the crystal defects play the main role in improving hydrogen sorption properties of Mg-20wt.% Fe23Y8 composite.

  2. Microstructure and mechanical properties of newly developed aluminum–lithium alloy 2A97 welded by fiber laser

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Banglong [Key Laboratory for Liquid–Solid Structural Evolution and Processing of Materials Ministry of Education, Shandong University, Jinan 250061 (China); Qin, Guoliang, E-mail: glqin@sdu.edu.cn [Key Laboratory for Liquid–Solid Structural Evolution and Processing of Materials Ministry of Education, Shandong University, Jinan 250061 (China); Meng, Xiangmeng; Ji, Yang; Zou, Yong [Key Laboratory for Liquid–Solid Structural Evolution and Processing of Materials Ministry of Education, Shandong University, Jinan 250061 (China); Lei, Zhen [Harbin Welding Institute, Harbin 150028 (China)

    2014-11-03

    The newly developed aluminum–lithium alloy 2A97 was for the first time joined by laser beam welding in order to meet the ever-increased long-term requirements of aerospace, aviation and armament industries. The weld appearance, microstructure, solute segregation, precipitate behavior, and their relationships with mechanical properties of welded joints were investigated. Sound joints with no crack and a few small porosities are obtained under appropriate heat inputs. As a result of heterogeneous nucleation involving the effect of Zr and Li, a non-dendritic equiaxed zone forms between partially melted zone and fusion zone. The crystal morphologies in fusion zone vary from columnar dendrite to equiaxed dendrite, with the increase of constitutional supercooling. Solute segregation leads to the variations of Cu content in grain interior and boundary, as well as the weak ability of re-precipitation of fusion zone. Most precipitates in the base metal dissolve during welding, and fusion zone contains a decreased quantity of δ′, β′, θ′, and T{sub 1}. The ultimate tensile strength of laser welded joints is 83.4% of that of the base metal, and can meet the application requirements from related industries, but the ductility still needs to be improved. Welding defects and loss of solid solution/precipitation hardened structure lead to the degradation of mechanical properties. Tensile fracture occurs in weld with the brittle intergranular dominated mode and premature failure occurs and extends in the equiaxed zone.

  3. Microstructural Evolution and Functional Properties of Fe-Mn-Al-Ni Shape Memory Alloy Processed by Selective Laser Melting

    Science.gov (United States)

    Niendorf, Thomas; Brenne, Florian; Krooß, Philipp; Vollmer, Malte; Günther, Johannes; Schwarze, Dieter; Biermann, Horst

    2016-06-01

    In the current study, a Fe-Mn-Al-Ni shape memory alloy is processed by additive manufacturing for the first time. Microstructural evolution upon processing is strongly affected by thermal gradients and solidification velocity and, thus, by processing parameters and the actual specimen geometry. By single-step solutionizing heat treatment pronounced grain growth is initiated leading to microstructures showing good reversibility. The compressive stress-strain response revealed maximum reversible pseudo-elastic strain of about 7.5 pct. Critical steps toward further optimization of additively manufactured Fe-Mn-Al-Ni shape memory alloys are discussed.

  4. Property measurements on spray formed Si-Al alloys

    Institute of Scientific and Technical Information of China (English)

    WEI Yan-guang; XIONG Bai-qing; ZHANG Yong-an; LIU Hong-wei; WANG Feng; ZHU Bao-hong

    2007-01-01

    A novel Si-Al alloy was prepared by spray forming process for electronic packaging. Property measurements on spray-formed Si-Al alloys after hot pressing were carried out. The results indicate that the alloys (Si-(30%-40%)Al) have advantageous physical and mechanical characteristics, including low coefficient of thermal expansion (6.9×10-6-8.7×10-6/K), high thermal conductivity (118-127 W/(m·K)), low density (2.421×103-2.465×103 kg/m3), high ultimate flexural strength (180-220 MPa) and Brinell hardness (162-261). The alloys are easy to machine to tight tolerances using standard machine tools and they can be electroplated with gold finishes and soldered with Sn-Pb alloy without any difficulty.

  5. Properties and Application of Iron-based Shape Memory Alloy

    Institute of Scientific and Technical Information of China (English)

    Li Jian-chen; Jiang Qing; Dai Jun

    2005-01-01

    The properties of FeMnSiCrNi shape memory alloy were investigated. The results show that the best shape memory effect of Fel4Mn6Si9Cr5Ni alloy is 85%. The transformation amount of the ε→γ transformation is not complete after heating the alloy to 1000 K, As and Af points drop with increased transformation enthalpy ( △Hγ→ε) by thermal cycling and increased prestrain. The alloy shows also good creep and stress relaxation resistance. In addition, the alloy having a tensile force of 20 kN and a sealing pressure of 6 MPa can satisfy requirements for possible industrial application on pipe joints.

  6. Microstructure and Mechanical Properties of Friction Welding Joints with Dissimilar Titanium Alloys

    OpenAIRE

    Yingping Ji; Sujun Wu; Dalong Zhao

    2016-01-01

    Titanium alloys, which are important in aerospace application, offer different properties via changing alloys. As design complexity and service demands increase, dissimilar welding of the titanium alloys becomes a particular interest. Linear friction welding (LFW) is a relatively novel bond technique and has been successfully applied for joining titanium alloys. In this paper, dissimilar joints with Ti-6Al-4V and Ti-5Al-2Sn-2Zr-4Mo-4Cr alloys were produced by LFW process. Microstructure was s...

  7. Bacteria Adherence Properties of Nitrogen-Doped TiO2 Coatings by Plasma Surface Alloying Technique

    Institute of Scientific and Technical Information of China (English)

    WANG Hefeng; TANG Bin; LIN Naiming; LI Xiuyan; FAN Ailan; SHU Xuefeng

    2012-01-01

    In order to obtain a high-performance surface on 316L stainless steel (S.S) that can meet the requirements in medical material field environment,nitrogen-doped titanium dioxide (TiO2-xNx) was synthesized by oxidative annealing the resulted TiNx coatings in air.Titanium nitride coatings on 316L S.S were obtained by plasma surface alloying technique.The as-prepared coatings were characterized by X-ray diffraction,glow discharge optical emission spectrometer (GDOES),scanning electron microscopy and X-ray photoelectron spectroscopy,respectively.The bacteria adherence property of the TiO2-xNx coatings on S.S on the oral bacteria Streptococcus Mutans was investigated and compared with that of S.S by fluorescence microscopy.The mechanism of the bacteria adherence was discussed.The results show that the TiO2-xNx coatings are composed of anatase crystalline structure.SEM measurement indicates a rough surface morphology with three-dimensional homogenous protuberances after annealing treatment.Because of the photocatalysis and positive adhesion free energy,the TiO2-xNx coatings inhibit the bacteria adherence.

  8. Microstructure and mechanical properties of Pb-4%Sb alloy processed by equal channel angular pressing

    Directory of Open Access Journals (Sweden)

    Roberto Braga Figueiredo

    2006-03-01

    Full Text Available Equal Channel Angular Pressing (ECAP is the most prominent SPD (Severe Plastic Deformation method for the production of ultrafine and nanostructured metals, and has been extensively employed and analyzed. This technique was applied to a Pb-4%Sb alloy at room temperature, in order to study its effect on a low melting point and multiphase metallic material. The material was subjected to effective strains higher than 9, after 8 passes of processing, where dynamic and static recrystallization are expected during and after each pass. This eliminates any grain refinement and allows the analysis only of the microstructural effects associated with second phase redistribution and eventual precipitate dissolution. ECAP followed route C, which eliminates structural alignment after each even ECAP pass, facilitating the study of the microstructural evolution. It is shown that three ECAP passes are necessary to completely break the lamellar structure of the as cast strucure and that antimony dissolves into the lead rich matrix. Dynamic recrystallization and structural changes reduce the material strength and change the flow curve format.

  9. Microstructure, mechanical properties and electrical conductivity of Cu–0.3Mg–0.05Ce alloy processed by equal channel angular pressing and subsequent annealing

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Guang [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Li, Zhou, E-mail: lizhou6931@csu.edu.cn [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); State Key Laboratory of Powder Metallurgy, Changsha 410083 (China); Yuan, Yuan [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Lei, Qian [School of Materials Science and Engineering, Central South University, Changsha 410083 (China); Key Laboratory of Nonferrous Metal Materials Science and Engineering, Ministry of Education, Changsha 410083 (China)

    2015-08-15

    Highlights: • Minor Ce addition can deprive harmful elements and purify the Cu–Mg alloy. • Decrease of Mg content can effectively enhance the conductivity of Cu–Mg alloy. • Ultrafine-grained Cu–Mg–Ce alloy was successfully gained by 8 passes of ECAP. • The strength of Cu–Mg–Ce alloy can be significantly improved by ECAP. • Better comprehensive properties than the commercial Cu–Mg alloy are gained. - Abstract: A Cu–0.3 wt.%Mg–0.05 wt.%Ce alloy was designed and prepared by melting and casting. After hot rolled, the ingot was cut into rod-shape samples for equal channel angular pressing (ECAP) with different passes at room temperature. The microstructure evolutions were investigated using transmission electron microscope (TEM) observation and electron backscatter diffraction (EBSD) analysis. The severe plastic deformation (SPD) caused by ECAP made the grains elongated significantly. With the increase of ECAP passes, the fraction of high-angle boundaries (HABs) (θ ⩾ 15°) increased and the microstructure was refined. Tension testing results indicated that the tensile strength was remarkably improved from 273.4 MPa before ECAP to 587.5 MPa after 8 passes of ECAP, maintaining an appropriate elongation of 11.4% and good electrical conductivity of 73.1%IACS. After annealing treatment at 300 °C for 2 h, the ECAP samples still maintained excellent comprehensive properties: tensile strength was 558.2 MPa, electrical conductivity was 74.7%IACS, and elongation was 13.2%, which showed bright prospect in high-speed railway as a contact wire material.

  10. Property Criteria for Automotive Al-Mg-Si Sheet Alloys

    Directory of Open Access Journals (Sweden)

    Ramona Prillhofer

    2014-07-01

    Full Text Available In this study, property criteria for automotive Al-Mg-Si sheet alloys are outlined and investigated in the context of commercial alloys AA6016, AA6005A, AA6063 and AA6013. The parameters crucial to predicting forming behavior were determined by tensile tests, bending tests, cross-die tests, hole-expansion tests and forming limit curve analysis in the pre-aged temper after various storage periods following sheet production. Roping tests were performed to evaluate surface quality, for the deployment of these alloys as an outer panel material. Strength in service was also tested after a simulated paint bake cycle of 20 min at 185 °C, and the corrosion behavior was analyzed. The study showed that forming behavior is strongly dependent on the type of alloy and that it is influenced by the storage period after sheet production. Alloy AA6016 achieves the highest surface quality, and pre-ageing of alloy AA6013 facilitates superior strength in service. Corrosion behavior is good in AA6005A, AA6063 and AA6016, and only AA6013 shows a strong susceptibility to intergranular corrosion. The results are discussed below with respect to the chemical composition, microstructure and texture of the Al-Mg-Si alloys studied, and decision-making criteria for appropriate automotive sheet alloys for specific applications are presented.

  11. Data on the impact of increasing the W amount on the mass density and compressive properties of Ni–W alloys processed by spark plasma sintering

    Science.gov (United States)

    Sadat, T.; Hocini, A.; Lilensten, L.; Faurie, D.; Tingaud, D.; Dirras, G.

    2016-01-01

    Bulk Ni–W alloys having composite-like microstructures are processed by spark plasma sintering (SPS) route of Ni and W powder blends as reported in a recent study of Sadat et al. (2016) (DOI of original article: doi:10.1016/j.matdes.2015.10.083) [1]. The present dataset deals with determination of mass density and evaluation of room temperature compressive mechanical properties as function of the amount of W (%wt. basis). The presented data concern: (i) measurement of the mass of each investigated Ni–W alloy which is subsequently used to compute the mass density of the alloy and (ii) the raw (stress (MPa) and strain (ΔLL0)) data, which can be subsequently used for stress/ strain plots. PMID:27158658

  12. Data on the impact of increasing the W amount on the mass density and compressive properties of Ni-W alloys processed by spark plasma sintering.

    Science.gov (United States)

    Sadat, T; Hocini, A; Lilensten, L; Faurie, D; Tingaud, D; Dirras, G

    2016-06-01

    Bulk Ni-W alloys having composite-like microstructures are processed by spark plasma sintering (SPS) route of Ni and W powder blends as reported in a recent study of Sadat et al. (2016) (DOI of original article: doi:10.1016/j.matdes.2015.10.083) [1]. The present dataset deals with determination of mass density and evaluation of room temperature compressive mechanical properties as function of the amount of W (%wt. basis). The presented data concern: (i) measurement of the mass of each investigated Ni-W alloy which is subsequently used to compute the mass density of the alloy and (ii) the raw (stress (MPa) and strain ([Formula: see text])) data, which can be subsequently used for stress/ strain plots. PMID:27158658

  13. Processing magnesium alloys by severe plastic deformation

    Science.gov (United States)

    Figueiredo, Roberto B.; Aguilar, Maria Teresa P.; Cetlin, Paulo Roberto; Langdon, Terence G.

    2014-08-01

    The use of severe plastic deformation techniques for processing magnesium alloys has moved from the early difficulties of processing to a stage of tailoring the best properties of these materials. The present paper reviews processing, structure and mechanical properties characterization. It is shown that ultrafine-grained structures are obtained in magnesium alloys processed by multiple passes of Equal-Channel Angular Pressing at moderate temperatures. Ultrafine-grained structures are also obtained by room temperature processing by High- Pressure Torsion. The ultrafine-grained structures increase strength and introduce excellent superplastic capabilities in many magnesium alloys. Moreover, processing magnesium alloys by severe plastic deformation leads to the development of anisotropy in mechanical behavior.

  14. Study on the microstructure, mechanical property and residual stress of SLM Inconel-718 alloy manufactured by differing island scanning strategy

    Science.gov (United States)

    Lu, Yanjin; Wu, Songquan; Gan, Yiliang; Huang, Tingting; Yang, Chuanguang; Junjie, Lin; Lin, Jinxin

    2015-12-01

    Inconel-718 has received an extensive using in mold industry. The selective laser melting (SLM) is providing an ideal means for manufacturing mold insert with complex geometrical features and internal architecture. During the manufacturing of high quality mold inserts with conformal cooling channel, the parameters play a vital role in the SLM process. In the study, the Inconel-718 alloys were manufactured by SLM with 2×2 mm2, 3×3 mm2, 5×5 mm2, and 7×7 mm2 island scanning strategies. The microstructure, mechanical property, and residual stress were investigated by optical microscope, tensile test and Vickers micro-indentation, respectively. It can be found that the relative density increased with enlarging the island size; the results on the microstructure indicated that the cracks and more pores were detected in the 22-specimen; whilst the microstructures of all specimens were composed of fine dendritic grains, cellular, and columnar structures; the tensile testing suggested that the ultimate tensile strength and yield strength of all samples was similar; while the outcome of the residual stress showed that the value of residual stress was ranked in the following sequence: 22-specimen<55-specimen<77-specimen<33-specimen. Although the 22-specimen had lower residual stress compared with the other groups, the occurrence of cracks limited its processing application in SLM. Through integrated into account, the 55-scanning strategy is a promising candidate for manufacturing of mold inserts.

  15. POWDER METALLURGY TiAl ALLOYS: MICROSTRUCTURES AND PROPERTIES

    Energy Technology Data Exchange (ETDEWEB)

    Hsiung, L

    2006-12-11

    The microstructures and properties of powder metallurgy TiAl alloys fabricated by hot extrusion of gas-atomized powder at different elevated temperatures were investigated. Microstructure of the alloy fabricated at 1150 C consisted of a mixture of fine ({gamma} + {alpha}{sub 2}) equiaxed grains and coarse ordered B2 grains. Particles of ordered hexagonal {omega} phase were also observed in some B2 grains. The alloy containing B2 grains displayed a low-temperature superplastic behavior: a tensile elongation of 310% was measured when the alloy was tested at 800 C under a strain rate of 2 x 10{sup -5} s{sup -1}. Microstructure of the alloy fabricated at 1250 C consisted of a mixture of fine ({gamma} + {alpha}{sub 2}) equiaxed grains, coarse {alpha}{sub 2} grains, and lamellar ({gamma} + {alpha}{sub 2}) colonies. An observation of stacking faults associated with fine {gamma} lamellae in {alpha}{sub 2} grains reveals that the stacking fault of {alpha}{sub 2} phase plays an important role in the formation of lamellar ({gamma} + {alpha}{sub 2}) colonies. Unlike the alloy fabricated at 1150{sup o}, the alloy fabricated at 1250{sup o} displayed no low-temperature superplasticity, but a tensile elongation of 260% at 1000 C was measured. Microstructure of the alloy fabricated at 1400 C consisted of fully lamellar ({gamma} + {alpha}{sub 2}) colonies with the colony size ranging between 50 {micro}m and 100 {micro}m, in which the width of {gamma} lamella is in a range between 100 nm and 350 nm, and the width of {alpha}{sub 2} lamella is in a range between 10 nm and 50 nm. Creep behavior of the ultrafine lamellar alloy and the effects of alloying addition on the creep resistance of the fully lamellar alloy are also investigated.

  16. Growth of epitaxial Pt1-xPbx alloys by surface limited redox replacement and study of their adsorption properties.

    Science.gov (United States)

    Mercer, M P; Plana, D; Fermίn, D J; Morgan, D; Vasiljevic, N

    2015-10-01

    The surface limited redox replacement (SLRR) method has been used to design two-dimensional Pt-Pb nanoalloys with controlled thickness, composition, and structure. The electrochemical behavior of these alloys has been systematically studied as a function of alloy composition. A single-cell, two-step SLRR protocol based on the galvanic replacement of underpotentially deposited monolayers of Pb with Pt was used to grow epitaxial Pt1-xPbx (x up to 10 ML thickness on Au substrates. It is shown that by varying the terminating potential of the galvanic replacement step, the Pb atomic content can be controlled in the films. Electrochemical analysis of the alloys showed that the adsorption of both H and CO exhibits similar, and systematic, decreases with small increases in the Pb content. These measurements, commonly used in electrocatalysis for the determination of active surface areas of Pt, suggested area values much lower than those expected based on the net Pt composition in the alloy as measured by XPS. These results show that Pb has a strong screening effect on the adsorption of both H and CO. Moreover, changes in alloy composition result in a negative shift in the potential of the peaks of CO oxidation that scales with the increase of Pb content. The results suggest electronic and bifunctional effects of incorporated Pb on the electrochemical behavior of Pt. The study illustrates the potential of the SLRR methodology, which could be employed in the design of 2-dimensional bimetallic Pt nanoalloys for fundamental studies of electrocatalytic behavior in fuel cell reactions dependent on the nature of alloying metal and its composition. PMID:26372676

  17. Effect of cathode vibration and heat treatment on electromagnetic properties of flake-shaped diatomite coated with Ni–Fe alloy by electroplating

    Energy Technology Data Exchange (ETDEWEB)

    Lan, Mingming, E-mail: lan_mingming@163.com; Li, Huiqin; Huang, Weihua; Xu, Guangyin; Li, Yan

    2015-03-01

    In this paper, flake-shaped diatomite particles were used as forming templates for the fabrication of the ferromagnetic functional fillers by way of electroplating Ni–Fe alloy method. The effects of cathode vibration frequency on the content of Ni–Fe alloy in the coating and the surface morphologies of the coatings were evaluated. The electromagnetic properties of the coated diatomite particles before and after heat treatment were also investigated in detail. The results show that the core-shell flake-shaped diatomite particles with high content of Ni–Fe alloy and good surface qualities of the coatings can be obtained by adjusting cathode vibration frequency. The coated diatomite particles with heat treatment filled paraffin wax composites exhibit a superior microwave absorbing and electromagnetic properties compared to the non-heat treated samples. Additionally, the peaks of reflection loss are found to be able to shift to lower frequency by the heat treatment process, which indicates the heat treatment can adjust microwave absorbing frequency band. - Highlights: • We used the diatomite particles as template to fabricate the flake-shaped ferromagnetic fillers. • The diatomite particles were deposited pure magnetic Ni–Fe alloy by electroplating methods. • The coated diatomite particles were lightweight ferromagnetic fillers. • The composites containing coated diatomite particles with heat treatment exhibited great potential in the field of electromagnetic absorbing.

  18. Structure and tensile properties of ferro-martensitic alloys hardened by chi phase precipitation

    International Nuclear Information System (INIS)

    Transformation of ferrite into austenite and of austenite into martensite, precipitation of intermetallic phases and tensile properties of the steel Cr13-Mo1.5 are studied in function of Ti additions (from 0 to 3%) and Ni additions (from 2 to 8%) for its mechanical resistance at 400-6500C. 12 references are given

  19. Electrochemical properties of TiV-based hydrogen storage alloys

    Institute of Scientific and Technical Information of China (English)

    朱云峰; 李锐; 高明霞; 刘永锋; 潘洪革; 王启东

    2003-01-01

    The electrochemical properties of the super-stoichiometric TiV-based hydrogen storage electrode alloys(Ti0.8Zr0.2)(V0.533Mn0.107Cr0.16Ni0.2)x(x=2, 3, 4, 5, 6) were studied. It is found by XRD analysis that all the al-loys mainly consist of a C14 Laves phase with hexagonal structure and a V-based solid solution phase with BCCstructure. The lattice parameters and the unit cell volumes of the two phases decrease with increasing x. The cyclelife, the linear polarization, the anode polarization and the electrochemical impedance spectra of the alloy electrodeswere investigated systematically. The overall electrochemical properties of the alloy electrode are found improvedgreatly as the result of super-stoichiometry and get to the best when x= 5.

  20. Deposition of DLC Coating on Biomedical TiNi Alloys by Plasma Based Ion Implantation to Improve Surface Properties

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Diamond-like carbon ( DLC ) -films were successfully deposited on Ti- 50.8at% Ni using plasma based ion implantation (PBII) technique. The influence of the pulsed negative bias voltage applied to the substrate from 12 kV to 40 kV on the microstructure, nano- indentation hardness and Young' s modulus, the surface characteristics and corrosion resistant property as well as hemocompatibility were investigated. The experimental results showed that C 1 s peak depended heavily on the bias voltage. With the increase of bias voltage , the ratio of sp2 / sp3 -first decreased, renching a minimum value at 20 kV, and then increased. The DLC coating deposited at20 kV showed the highest hardness and elastic modulus values as a result of lower sp2 / sp3 ratio. The RMS values first decreased from 7.202 nm( 12 kV) to 5.279 nm(20 kV), and then increased to 11.449 nm(30 kV) and7.060 nm(40 kV). The uncoated TiNi alloy showed severe pitting corrosion, due to the presence of Cl-ions in the solution. On the contrary, the DLC coated sample showed very little pitting corrosion and behaved better corrosion resistant property especially for the specimens deposited at 20 kV bias voltages. The platelet adhesion test show that the hemocompatibility of DLC coated TiNi alloy is much better than that of bare TiNi alloy, and the hemocompatibility performauce of DLC coated TiNi alloy deposited at 20 kV is superior to that of other coated specimens.

  1. Preparation of TiMn alloy by mechanical alloying and spark plasma sintering for biomedical applications

    Science.gov (United States)

    Zhang, F.; Weidmann, A.; Nebe, B. J.; Burkel, E.

    2009-01-01

    TiMn alloy was prepared by mechanical alloying and subsequently consolidated by spark plasma sintering (SPS) technique for exploration of biomedical applications. The microstructures, mechanical properties and cytotoxicity of the TiMn alloys were investigated in comparison with the pure Ti and Mn metals. Ti8Mn and Ti12Mn alloys with high relative density (99%) were prepared by mechanical alloying for 60 h and SPS at 700 °C for 5 min. The doping of Mn in Ti has decreased the transformation temperature from α to β phase, increased the relative density and enhanced the hardness of the Ti metal significantly. The Ti8Mn alloys showed 86% cell viability which was comparable to that of the pure Ti (93%). The Mn can be used as a good alloying element for biomedical Ti metal, and the Ti8Mn alloy could have a potential use as bone substitutes and dental implants.

  2. Production, Properties and Applications of Bulk Amorphous Alloys

    Institute of Scientific and Technical Information of China (English)

    Tao Zhang; Akihisa Inoue

    2000-01-01

    A review is given of recent work concerned with the production method, the characteristic properties(1) Bulk amorphous system; (2) Mechanical and magnetic properties of bulkamorphous alloys; (3)application of bulk amorphous alloys.

  3. Stability of metastable phase and soft magnetic properties of bulk Fe-B nano-eutectic alloy prepared by undercooling solidification combined with CU-mold chilling

    Science.gov (United States)

    Yang, Changlin; Zhang, Jun; Huang, Huili; Song, Qijiao; Liu, Feng

    2015-11-01

    Bulk Fe83B17 nano-eutectic alloys were prepared by undercooling solidification combined with Cu-mold chilling method. Stable phase Fe2B and metastable phase Fe3B were found to coexist in the as-solidified microstructure. The soft magnetic properties were improved significantly by the nano-lamellar eutectic and the metastable phase and, were increased further by annealing at 1173 K for 1.5 h after which the metastable phase was decomposed completely.

  4. Magnetic properties and microwave absorption properties of short carbon fibres coated by Ni–Fe alloy coatings

    Indian Academy of Sciences (India)

    Ying Liu; Chengwen Qiang

    2015-12-01

    Ni–Fe alloy coatings were successfully prepared on carbon fibre (CF) surfaces bymeans of electroplating at 25°C for 560 s. The structures and morphologies of the composite were characterized using X-ray diffraction and scanning electron microscopy. The coercivity () and saturation magnetization () of the Fe0.45Ni0.55/CF composites were 45.19 Oe and 1513.59 emu g−1, respectively. The reflectivity of Fe0.45Ni0.55/CF composites was less than −5 dB over the range of 1.1–5.4 GHz. The reflectivity of Fe0.45Ni0.55/CF composites was less than −10 dB over the range of 1.6–2.1 GHz. The lowest reflectivity of the Fe0.45Ni0.55/CF composites was −14.7 dB at 2.0 GHz and the corresponding thickness was 3.3 mm.

  5. Structure and tensile properties of ferro-martensitic alloys hardened by chi phase precipitation

    International Nuclear Information System (INIS)

    Transformation of ferrite into austenite and of austenite into martensite, precipitation of intermetallic phases and tensile properties of the steel Cr13-Mo1.5 are studied in function of Ti additions (from 0 to 3%) and Ni additions (from 2 to 8%) for its mechanical resistance at 400-6500C for using it as fuel cladding of fast neutron reactors. 12 references are given

  6. Mechanical and tribological properties of the surface layer of the hot work tool steel obtained by laser alloying

    Directory of Open Access Journals (Sweden)

    K. Lukaszkowicz

    2007-07-01

    Full Text Available Purpose: The paper presents results on the mechanical and tribological properties examinations of the X40CRMoV5-1 hot work alloy tool steel alloyed with carbide powders using the high power diode laser (HPDL.Design/methodology/approach: Metallographic examinations of the material structures after laser alloying of their surface layer were made on light microscope. The tribological wear relationships using pin-on-disc test were specified for surface layers subject to laser treatment, determining the friction coefficient, and mass loss of the investigated surfaces. Hardness tests were made with Rockwell method in C scale on specimens subjected to the standard heat treatment and alloyed using the high power diode laser at various parameters. X-ray diffraction (XRD technique was used to investigate crystalline structure and phases in the layers.Findings: Metallographic examinations carried out on the light microscope confirm that the structure of the material solidifying after laser remelting is diversified, which is dependant on the solidification rate of the investigated steels. The investigations carried out made it possible to state that due to the heat treatment and remelting of the X40CrMoV5-1tool steel with the WC, TaC or TiC powders it is possible to obtain the high quality surface layer with no cracks and defects and with hardness significantly higher than the substrate metal.Research limitations/implications: In order to evaluate with more detail the possibility of applying these surface layers in tools, further investigations should be concentrated on the determination of the thermal fatigue resistance of the layers.Practical implications: The alloyed layers which were formed on the surface of the hot work steel have shown significant improvement. Good properties of the laser treatment make these layers suitable for various technical and industrial applications.Originality/value: A modification of tool steels surface using a laser beam

  7. Optical properties of Mn doped ZnO films and wires synthesized by thermal oxidation of ZnMn alloy

    Energy Technology Data Exchange (ETDEWEB)

    Sima, M., E-mail: msima@infim.ro [National Institute of Materials Physics, 105bis Atomistilor Street, 077125 Magurele (Romania); Mihut, L. [National Institute of Materials Physics, 105bis Atomistilor Street, 077125 Magurele (Romania); Vasile, E. [University “Politehnica”of Bucharest, Faculty of Applied Chemistry and Material Science, Department of Oxide Materials and Nanomaterials, No. 1-7 Gh. Polizu Street, 011061 Bucharest (Romania); Sima, Ma.; Logofatu, C. [National Institute of Materials Physics, 105bis Atomistilor Street, 077125 Magurele (Romania)

    2015-09-01

    Mn doped ZnO films and wires, having different manganese concentrations were synthesized by thermal oxidation of the corresponding ZnMn alloy films and wires electrodeposited on a gold substrate. Structural and optical properties were addressed with scanning electron microscopy, X-ray diffraction (XRD), Raman scattering and photoluminescence (PL). To estimate the manganese concentration in Mn doped ZnO films, X-ray photoelectron spectroscopy was used. XRD patterns indicate that the incorporation of Mn{sup 2+} ions into the Zn{sup 2+} site of ZnO lattice takes place. Quenching of the ZnO PL appears due to Mn{sup 2+} ions in the ZnO lattice. Moreover, a significant decrease in the green emission of ZnO is reported in the case of the Mn doped ZnO wire array with a Mn concentration of 1.45%. The wurtzite ZnO has a total of 12 phonon modes, namely, one longitudinal acoustic (LA), two transverse acoustic (TA), three longitudinal optical (LO), and six transverse optical branches. Compared to the undoped ZnO, a gradual up-shift of the Raman lines assigned to the 2LA and A{sub 1} (LO) vibrational modes, from 482 and 567 cm{sup −1} to 532 and 580 cm{sup −1}, respectively, takes place for the Mn doped ZnO films having a Mn concentration between 2 and 15%. Additionally, in the case of the Mn doped ZnO films with 7 and 15% Mn concentration, Raman spectra show the appearance and increase in the relative intensity of the ZnO Raman line assigned to the TA + LO vibrational mode in the 600–750 cm{sup −1} spectral range. For the Mn-doped ZnO wires, the presence of the Raman line peaking at 527 cm{sup −1} confirms the insertion of Mn{sup 2+} ions in ZnO lattice. - Highlights: • Mn doped ZnO films and wires grown by thermal oxidation of ZnMn alloy • Incorporation of Mn{sup 2+} ions into Zn{sup 2+} site of ZnO lattice • Appearance of a strong Raman line in the spectral range 600–800 cm{sup −1} at high Mn concentration • Compensation of the oxygen vacancy at higher

  8. On the mechanical properties of TiNb based alloys

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Y. [SIMAP-CNRS, Institut Polytechnique de Grenoble, BP 75, St. Martin d’Hères 38402 (France); Georgarakis, K. [WPI Advanced Institute for Materials Research, Tohoku University, Sendai (Japan); SIMAP-CNRS, Institut Polytechnique de Grenoble, BP 75, St. Martin d’Hères 38402 (France); Yokoyama, Y. [WPI Advanced Institute for Materials Research, Tohoku University, Sendai (Japan); Yavari, A.R., E-mail: euronano@minatec.inpg.fr [SIMAP-CNRS, Institut Polytechnique de Grenoble, BP 75, St. Martin d’Hères 38402 (France)

    2013-09-15

    Highlights: •Systematic study of compressive behaviors of TiNb based alloys in different states. •Comparison between X-ray diffraction results in reflection and transmission mode. •High melting temperature TiNb based alloys were fabricated by copper mold casting. •Textures of studied alloys are analyzed through synchrotron radiation data. -- Abstract: A series of TiNb(Sn) alloys were synthesized by copper mold suction casting and subjected to different heat treatments (furnace cooling or water quenching). The microstructure, thermal and mechanical properties of the as-cast and heat treated samples were investigated. For the Ti–8.34 at.% Nb alloy, the as-cast and water quenched samples possess martensitic α′′ phase at room temperature and compression tests of these samples show occurrence of shape memory effect. For β phase Ti–25.57 at.% Nb alloys, stress-induced martensitic transformation was found during compression in the as-cast and water quenched samples. For the ternary Ti–25.05 at.%Nb–2.04 at.%Sn alloy, conventional linear elastic behavior was observed. It is shown that the addition of Sn increases the stability of the β phase. The Young’s moduli of these alloys were also measured by ultrasonic measurements. Water-quenched Ti–25.57 at.%Nb alloy was found to exhibit the lowest Young’s modulus value. Sn addition has small impact on the Young’s moduli of the TiNb alloys.

  9. An Analysis of Selected Properties of ZA Alloys

    Science.gov (United States)

    Gervais, E.; Barnhurst, R. J.; Loong, C. A.

    1985-11-01

    Zinc-aluminum (ZA) alloys are a relatively new family of zinc foundry alloys having superior melting and casting characteristics and attractive mechanical properties. The ZA-8 and ZA-12 alloys are moderate to high strength materials while ZA-27 is a high-strength alloy. All can be sand cast, permanent molded and pressure die cast. An extensive characterization program is being implemented to develop appropriate and reliable engineering data for designers. Property development in all aspects of ZA metallurgy is welladvanced. The data available on selected physical and mechanical properties of ZA alloys is compared here with the properties of traditional casting alloys.

  10. Microstructural evolution and mechanical, and corrosion property evaluation of Cu-30Ni alloy formed by Direct Metal Deposition process

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharya, S., E-mail: sudipb@umich.edu [University of Michigan, 2350 Hayward Street, 2040 G.G. Brown Laboratories, Ann Arbor, MI 48109 (United States); Dinda, G.P.; Dasgupta, A.K. [Center for Advanced Technologies, Focus: HOPE, Detroit, MI 48238 (United States); Natu, H.; Dutta, B. [POM Group Inc., Auburn Hills, MI 48326 (United States); Mazumder, J. [University of Michigan, 2350 Hayward Street, 2040 G.G. Brown Laboratories, Ann Arbor, MI 48109 (United States); POM Group Inc., Auburn Hills, MI 48326 (United States)

    2011-06-02

    Research highlights: > Cu-30Ni alloy was successfully deposited with CO{sub 2} laser DMD system on C71500 substrate. > The microstructure consists of a single solid solution phase. > Columnar dendrites growing into equiaxed dendrites form layer microstructure. > Dendrite growth direction and angle relative to substrate was maintained in each layer. > Lattice parameter of solid solution phase is longer than reported lattice parameters. - Abstract: In the current investigation Cu-30Ni alloy was successfully laser deposited on a rolled C71500 plate substrate by Direct Metal Deposition technology. The microstructural investigation of the clad was performed using optical and scanning electron microscopy. The phase and crystal structure analysis was performed using X-ray diffraction technique and transmission electron microscopy. The microstructure consisted of columnar and equiaxed dendrites with face centered cubic crystal structure. The dendrites grew epitaxially from the substrate and layer and bead boundaries. Dendrites' growth direction <0 0 1> and growth angle 60{sup o} was maintained in each layer. The average primary dendritic arm spacing at the bottom part of the layers was about 7.5 {mu}m and average secondary dendritic arm spacing in the upper part of the layer varied between 2 {mu}m and 4.5 {mu}m. The lattice parameter of the identified phase was found to be longer than that reported in literature. The reported lattice parameters in literature are however from samples processed under equilibrium conditions. The microhardness of the clad was found to be less than the substrate but very consistent along the clad. Cu-30Ni clad specimen showed higher ultimate tensile strength but lower yield strength and percentage elongation as compared to the C71500 substrate. DMD Cu-30Ni clad/C71500 substrate specimen showed the worst mechanical properties. The corrosion resistance of the specimens was found to decrease in the order DMD Cu-30Ni clad, half-and-half DMD Cu

  11. Microstructure Characteristics and Mechanical Properties of Al-12Si Coatings on AZ31 Magnesium Alloy Produced by Cold Spray Technique

    Science.gov (United States)

    Hao, Yi; Wang, Ji-qiang; Cui, Xin-yu; Wu, Jie; Li, Tie-fan; Xiong, Tian-ying

    2016-06-01

    The cold spray technique was to deposit Al-12Si coatings on AZ31 magnesium alloy. The influence of gas pressure and gas temperature on the microstructure of coatings was investigated so as to optimize the process parameters. OM, SEM, and XRD were used to characterize the as-sprayed coatings. Mechanical properties including Vickers microhardness and adhesion strength were measured in order to evaluate coating quality. Test results indicate that the Al-12Si coatings possess the same crystal structure with powders, sufficient thickness, low porosity, high hardness, and excellent adhesion strength under optimal cold spray process parameters.

  12. Role of alloying additions on the properties of Cu–Al–Mn shape memory alloys

    Energy Technology Data Exchange (ETDEWEB)

    Dasgupta, Rupa, E-mail: rupadasgupta@ampri.res.in; Jain, Ashish Kumar; Kumar, Pravir; Hussain, Shahadat; Pandey, Abhishek

    2015-01-25

    Highlights: • Cu based SMAs with high transition temperature could be made using LM route. • The properties depend on alloying composition. • Property characterisation establishes feasibility of making SMAs. - Abstract: The effect of alloying seven different elements [Zn, Si, Fe, Ni, Mg, Cr and Ti] on the microstructure, hardness, phase precipitation and transformation temperature in a Cu–12.5Al–5Mn alloy with a view to possible improvements as a result of these additions is the focus of the reported study. The base alloy has been chosen keeping in mind its ability to exhibit shape memory properties and improved ductility over other Cu-based SMAs. The objective was to ascertain changes or improvements attained due to the individual tertiary additions. The samples were prepared through liquid metallurgy route using pure copper, aluminum, manganese and the respective quaternary alloying elements in right quantities to weigh 1000 g of the alloy in total and were melted together. Samples from the cast alloys were subject to homogenisation treatment at 200 °C for 2 h in a muffle furnace and furnace cooled. Samples from the homogenised alloys were heated and held for 2 h at 920 °C followed by ice quenching to obtain the desired martensitic structure for shape memory behaviour. The alloys in the cast, homogenised and quenched conditions were metallographically polished to observe the martensitic phase formation mainly in quenched samples which is a pre requisite for exhibiting shape memory properties in these alloys. X-ray Diffraction studies were carried out on the cast and quenched samples using Cu Kα target; and the phases identified indicate martensitic phase precipitation; however in some cases the precipitation is incomplete. Differential Scanning Calorimetric [DSC] studies were carried out on quenched samples from room temperature to 600 °C maintaining a constant rate of 10 °C/min. Results indicate clear transformation peaks in all the samples which

  13. Supercoducting property of Zr-Cu-Al-Ni-Nb alloys

    Science.gov (United States)

    Okai, D.; Motoyama, G.; Kimura, H.; Inoue, A.

    The superconducting property of Zr55Cu(30-X)Al10Ni5NbX alloys prepared by arc melting and liquid quenching methods was investigated by magnetic susceptibility measurements. The crystalline alloys with X = 0∼25 at.% prepared by arc melting method exhibited superconductivity with maximum Tc,on of 10.1 K. The alloys (X = 10∼23 at.%) with crystalline particles embedded in an amorphous structure, which were fabricated by melt spinning method, showed superconductivity with Tc,on of less than 4.0 K. The superconducting property of the Zr-Cu-Al-Ni-Nb alloys was attributed to superconducting phases of Zr2Cu, Zr2Ni, Zr65Al10Nb25 and Zr-Nb contained in the Zr-Cu-Al-Ni-Nb alloys. The melt-spun Zr55Cu(30-X)Al10Ni5NbX (X = 10∼20 at.%) alloys exhibited glass transition at 718∼743 K and were found to be superconducting metallic glasses.

  14. Anisotropic Transport Properties of Complex Metallic Alloys

    OpenAIRE

    Smontara, Ana; Dolinšek, Janez

    2010-01-01

    Anisotropic transport properties (electrical resistivity, ρ, and thermal conductivity, κ) of the Y-phase Al-Ni-Co, o-Al13Co4 and Al4(Cr,Fe) complex metallic alloys were investigated. They belong to the class of decagonal approximant phases with stacked-layer crystallographic structure and allowed us to study the evolution of anisotropic transport properties with increasing structural complexity and the unit cell size.

  15. Mechanical Properties of Niobium Alloyed Gray Iron

    OpenAIRE

    Hanna, Ivil

    2011-01-01

    The influence of adding an amount of 0.1% and 0.3% niobium to the gray iron alloy used for brake discs, these disc materials are called disc 16 respective 17, have been investigated at RT (room temperature). That is together with two other alloys, the reference disc which contains 0.32% molybdenum but lacks niobium and another one with neither niobium nor molybdenum in it, this is called disc material 15. Focus in this thesis work is on the mechanical properties of the studied materials and f...

  16. Evolution of Hydrogen Storage Alloys Prepared by Special Methods

    Institute of Scientific and Technical Information of China (English)

    Guo Hong; Zhang Ximin; Jing Hai; Li Chengdong; Xu Jun

    2004-01-01

    Microstructure characteristics and electrochemical properties of hydrogen storage alloys prepared by gas atomization, melt spinning and strip casting respectively were outlined.The advantages, disadvantages and research development of the above methods for preparing hydrogen storage alloys were explained.The strip casting is a new special means for preparing AB5 rare earth hydrogen storage alloys of high performance and low cost, and the study of the strip casting for preparing hydrogen storage alloys is presented specially.

  17. Effects of Al-Mn-Ti-P-Cu master alloy on microstructure and properties of Al-25Si alloy

    OpenAIRE

    Xu Chunxiang; Zhao Gaozhan; Zhang Jinshan

    2013-01-01

    To obtain a higher microstructural refining efficiency, and improve the properties and processing ability of hypereutectic Al-25Si alloy, a new environmentally friendly Al-20.6Mn-12Ti-0.9P-6.1Cu (by wt.%) master alloy was fabricated; and its modification and strengthening mechanisms on the Al-25Si alloy were studied. The mechanical properties of the unmodified, modified and heat treated alloys were investigated. Results show that the optimal addition amount of the Al-20.6Mn-12Ti-0.9P-6.1Cu ma...

  18. Investigation of mechanical properties for open cellular structure CoCrMo alloy fabricated by selective laser melting process

    Science.gov (United States)

    Azidin, A.; Taib, Z. A. M.; Harun, W. S. W.; Che Ghani, S. A.; Faisae, M. F.; Omar, M. A.; Ramli, H.

    2015-12-01

    Orthodontic implants have been a major focus through mechanical and biological performance in advance to fabricate shape of complex anatomical. Designing the part with a complex mechanism is one of the challenging process and addition to achieve the balance and desired mechanical performance brought to the right manufacture technique to fabricate. Metal additive manufacturing (MAM) is brought forward to the newest fabrication technology in this field. In this study, selective laser melting (SLM) process was utilized on a medical grade cobalt-chrome molybdenum (CoCrMo) alloy. The work has focused on mechanical properties of the CoCrMo open cellular structures samples with 60%, 70%, and 80% designed volume porosity that could potentially emulate the properties of human bone. It was observed that hardness values decreased as the soaking time increases except for bottom face. For compression test, 60% designed volume porosity demonstrated highest ultimate compressive strength compared to 70% and 80%.

  19. Effect of extrusion processing on the microstructure, mechanical properties, biocorrosion properties and antibacterial properties of Ti-Cu sintered alloys.

    Science.gov (United States)

    Zhang, Erlin; Li, Shengyi; Ren, Jing; Zhang, Lan; Han, Yong

    2016-12-01

    Ti-Cu sintered alloys, Ti-Cu(S) alloy, have exhibited good anticorrosion resistance and strong antibacterial properties, but low ductility in previous study. In this paper, Ti-Cu(S) alloys were subjected to extrusion processing in order to improve the comprehensive property. The phase constitute, microstructure, mechanical property, biocorrosion property and antibacterial activity of the extruded alloys, Ti-Cu(E), were investigated in comparison with Ti-Cu(S) by X-ray diffraction (XRD), optical microscopy (OM), scanning electronic microscopy (SEM) with energy disperse spectroscopy (EDS), mechanical testing, electrochemical testing and plate-count method in order to reveal the effect of the extrusion process. XRD, OM and SEM results showed that the extrusion process did not change the phase constitute but refined the grain size and Ti2Cu particle significantly. Ti-Cu(E) alloys exhibited higher hardness and compressive yield strength than Ti-Cu(S) alloys due to the fine grain and Ti2Cu particles. With the consideration of the total compressive strain, it was suggested that the extrusion process could improve the ductility of Ti-Cu alloy(S) alloys. Electrochemical results have indicated that the extrusion process improved the corrosion resistance of Ti-Cu(S) alloys. Plate-count method displayed that both Ti-Cu(S) and Ti-Cu(E) exhibited strong antibacterial activity (>99%) against S. aureus. All these results demonstrated that hot forming processing, such as the extrusion in this study, refined the microstructure and densified the alloy, in turn improved the ductility and strength as well as anticorrosion properties without reduction in antibacterial properties.

  20. Effect of extrusion processing on the microstructure, mechanical properties, biocorrosion properties and antibacterial properties of Ti-Cu sintered alloys.

    Science.gov (United States)

    Zhang, Erlin; Li, Shengyi; Ren, Jing; Zhang, Lan; Han, Yong

    2016-12-01

    Ti-Cu sintered alloys, Ti-Cu(S) alloy, have exhibited good anticorrosion resistance and strong antibacterial properties, but low ductility in previous study. In this paper, Ti-Cu(S) alloys were subjected to extrusion processing in order to improve the comprehensive property. The phase constitute, microstructure, mechanical property, biocorrosion property and antibacterial activity of the extruded alloys, Ti-Cu(E), were investigated in comparison with Ti-Cu(S) by X-ray diffraction (XRD), optical microscopy (OM), scanning electronic microscopy (SEM) with energy disperse spectroscopy (EDS), mechanical testing, electrochemical testing and plate-count method in order to reveal the effect of the extrusion process. XRD, OM and SEM results showed that the extrusion process did not change the phase constitute but refined the grain size and Ti2Cu particle significantly. Ti-Cu(E) alloys exhibited higher hardness and compressive yield strength than Ti-Cu(S) alloys due to the fine grain and Ti2Cu particles. With the consideration of the total compressive strain, it was suggested that the extrusion process could improve the ductility of Ti-Cu alloy(S) alloys. Electrochemical results have indicated that the extrusion process improved the corrosion resistance of Ti-Cu(S) alloys. Plate-count method displayed that both Ti-Cu(S) and Ti-Cu(E) exhibited strong antibacterial activity (>99%) against S. aureus. All these results demonstrated that hot forming processing, such as the extrusion in this study, refined the microstructure and densified the alloy, in turn improved the ductility and strength as well as anticorrosion properties without reduction in antibacterial properties. PMID:27612770

  1. Structure and properties of a layered steel/vanadium alloy/steel composite prepared by high-pressure torsion

    Science.gov (United States)

    Nikulin, S. A.; Rogachev, S. O.; Rozhnov, A. B.; Khatkevich, V. M.; Nechaikina, T. A.; Morozov, M. V.

    2016-04-01

    The microstructure and hardness of a layered steel 08Kh17T/V-10Ti-5Cr/steel 08Kh17T composite, which was prepared by torsion under a high hydrostatic pressure at temperatures of 20, 200, and 400°C, have been studied. Severe plastic deformation under used conditions is shown to provide good joining of layers, which is accompanied by their substantial hardening (from 2.0 to 3.5 times). During deformation at temperatures of 20 and 200°C, fragmentation of the vanadium alloy layer into thinner layers is observed; at 400°C, mainly a plane interface between the vanadium alloy and the steel layers is formed.

  2. Preparation Methods and Properties of PdCu Alloy Membrane for Hydrogen Transition

    Institute of Scientific and Technical Information of China (English)

    SUN Xiaoliang; MA Guang; LI Jin; ZHANG Ke

    2012-01-01

    Pd and Pd alloy membranes are of increasing interest for hydrogen separation and purification due to their good thermal stability,high permeability and perfect selectivity.PdCu alloy (60wt% Pd) membranes have similar hydrogen permeability compared with PdAg alloy; meanwhile,it is cheaper than PdAg alloy.Furthermore,it has been reported that PdCu membrane has better resistance to poisoning and deactivation by H2S impurity.This paper reviews the properties and manufacturing methods of PdCu alloy membrane,finally,introduced some achievement made by us on PdCu alloy membrane.

  3. Influence of phytic acid concentration on coating properties obtained by MAO treatment on magnesium alloys

    International Nuclear Information System (INIS)

    Anodic coatings were prepared by microarc oxidation (MAO) on AZ91HP in a base solution of 10 g/L NaOH with and without the addition of 0-12 g/L phytic acid (C6H18O24P6). The influences of C6H18O24P6 and its concentration on the conductivity and breakdown voltage were studied. The morphologies and compositions of anodic coatings were determined by environmental scanning electron microscope (ESEM) and energy dispersive X-ray spectroscopy (EDX). Potentiodynamic polarization test was performed in 3.5 wt.% NaCl solution to evaluate the corrosion resistance of anodic coatings. The results showed that with the increase of C6H18O24P6 concentration, the solution conductivity decreased while the values of breakdown voltage increased. EDX analysis showed that the coatings formed in solutions with C6H18O24P6 addition contained Mg, Al, O, C, P and a trance of Na. The addition of C6H18O24P6 into the base solution was helpful in coating formation and the coatings formed in the solution containing 8 g/L C6H18O24P6 exhibited the best pore uniformity and corrosion resistance.

  4. Influence of phytic acid concentration on coating properties obtained by MAO treatment on magnesium alloys

    Science.gov (United States)

    Zhang, R. F.; Zhang, S. F.; Duo, S. W.

    2009-06-01

    Anodic coatings were prepared by microarc oxidation (MAO) on AZ91HP in a base solution of 10 g/L NaOH with and without the addition of 0-12 g/L phytic acid (C 6H 18O 24P 6). The influences of C 6H 18O 24P 6 and its concentration on the conductivity and breakdown voltage were studied. The morphologies and compositions of anodic coatings were determined by environmental scanning electron microscope (ESEM) and energy dispersive X-ray spectroscopy (EDX). Potentiodynamic polarization test was performed in 3.5 wt.% NaCl solution to evaluate the corrosion resistance of anodic coatings. The results showed that with the increase of C 6H 18O 24P 6 concentration, the solution conductivity decreased while the values of breakdown voltage increased. EDX analysis showed that the coatings formed in solutions with C 6H 18O 24P 6 addition contained Mg, Al, O, C, P and a trance of Na. The addition of C 6H 18O 24P 6 into the base solution was helpful in coating formation and the coatings formed in the solution containing 8 g/L C 6H 18O 24P 6 exhibited the best pore uniformity and corrosion resistance.

  5. Properties and electrochemical behaviors of AuPt alloys prepared by direct-current electrodeposition for lithium air batteries

    International Nuclear Information System (INIS)

    AuPt catalyst has a prospective application in a lithium air battery because of its bi-function on catalyzing Oxygen Reduction Reaction (ORR) and Oxygen Evolution Reaction (OER). Electrodeposition is an in-situ convenient technology for catalyst preparation without chemical residue. In an acid electrolyte, AuPt alloy catalysts were electrodeposited on carbon paper. The effect of main salt concentration, electrodeposition time and current density were studied by deposit micromorphology observation, structure analyses and composition testing. Catalytic abilities of AuPt alloys were measured by cyclic voltammetry (CV) in an ionic liquid of EMI-TFSI/Li-TFSI [1- Ethyl - 3- methylimidazolium–bis (trifluoromethanesulphonyl) imide/lithium–bis (trifluoromethanesulphonyl) imide]. The electrochemical behaviors of Au, Pt and AuPt deposits were also measured. An optimized direct-current electrodeposition process of getting high active AuPt catalyst is concluded, which is an aqueous solution containing 6.7∼10 mmol · L−1 HAuCl4, 10∼13.3 mmol · L−1 H2PtCl6 and 0.5 mol · L−1 H2SO4 as the electrolyte, current density of 20mA · cm−2 and electrodeposition time of 8∼34 s. The co-deposition of AuPt alloy is an irregular co-deposition controlled by diffusion, while gold atoms enter the platinum’s crystal lattice in the structure of AuPt alloy. The increase of the concentration of H2PtCl6 in the electrolyte, the extension of the electrodeposition time or the raise of the current density can improve the content of Pt in the deposit. The clusters’ diameters of AuPt catalysts decrease to 150∼250 nm by adjusting current densities during electrodeposition

  6. Influence of phytic acid concentration on coating properties obtained by MAO treatment on magnesium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, R.F., E-mail: rfzhang-10@163.com [Jiangxi Key Laboratory of Surface Engineering, Jiangxi Science and Technology Normal University, Nanchang 330013 (China) and School of Material Science and Engineering, Jiangxi Science and Technology Normal University, Nanchang 330013 (China); Zhang, S.F.; Duo, S.W. [Jiangxi Key Laboratory of Surface Engineering, Jiangxi Science and Technology Normal University, Nanchang 330013 (China); School of Material Science and Engineering, Jiangxi Science and Technology Normal University, Nanchang 330013 (China)

    2009-06-30

    Anodic coatings were prepared by microarc oxidation (MAO) on AZ91HP in a base solution of 10 g/L NaOH with and without the addition of 0-12 g/L phytic acid (C{sub 6}H{sub 18}O{sub 24}P{sub 6}). The influences of C{sub 6}H{sub 18}O{sub 24}P{sub 6} and its concentration on the conductivity and breakdown voltage were studied. The morphologies and compositions of anodic coatings were determined by environmental scanning electron microscope (ESEM) and energy dispersive X-ray spectroscopy (EDX). Potentiodynamic polarization test was performed in 3.5 wt.% NaCl solution to evaluate the corrosion resistance of anodic coatings. The results showed that with the increase of C{sub 6}H{sub 18}O{sub 24}P{sub 6} concentration, the solution conductivity decreased while the values of breakdown voltage increased. EDX analysis showed that the coatings formed in solutions with C{sub 6}H{sub 18}O{sub 24}P{sub 6} addition contained Mg, Al, O, C, P and a trance of Na. The addition of C{sub 6}H{sub 18}O{sub 24}P{sub 6} into the base solution was helpful in coating formation and the coatings formed in the solution containing 8 g/L C{sub 6}H{sub 18}O{sub 24}P{sub 6} exhibited the best pore uniformity and corrosion resistance.

  7. Structural and magnetic properties of holmium-scandium alloys and superlattices

    DEFF Research Database (Denmark)

    Bryn-Jacobsen, C.; Cowley, R.A.; McMorrow, D.F.;

    1997-01-01

    The properties of Ho-Sc alloys and superlattices grown by molecular-beam epitaxy have been investigated using x-ray and neutron-diffraction techniques. Structural studies reveal that the alloy samples have different a lattice parameters for the Sc-seed layer and the Ho:Sc alloy grown on top of th...

  8. Effects of Ce and Sb on the microstructure and properties of AZ91D magnesium alloy prepared by the EPC process

    Institute of Scientific and Technical Information of China (English)

    LI Jiqiang; DONG Xuanpu; FAN Zitian; WANG Yuanqing

    2008-01-01

    The effects of small amounts of cerium and antimony additions on the microstructure and the mechanical properties of AZ91D (Mg-9A1-Zn)based alloy were researched via the expendable pattern casting (EPC) process.The results show that the microstructure is obviously refined and the tensile strength of the AZ91D based alloy at ambient temperature is significantly improved.When compared to AZ91D,the AZ91D-1.0%Ce-0.4%Sb alloy has higher ultimate tensile strength and elongation.Its ultimate tensile strength and elongation are enhanced by 39% and 47%,respectively.The morphology of the tensile fracture of the AZ91D-1.0%Ce-0.4%Sb alloy has more characteristics of quasi-cleavage,This indicates that it has had a larger plastic deformation before failure.The tensile strength and elongation decrease with the increase of Ce and Sb contents because of the coarsening and volume increase of Cesb and Al11Ce3 phases.

  9. Electronic structure and mechanical properties of ternary ZrTaN alloys studied by ab initio calculations and thin-film growth experiments

    Science.gov (United States)

    Abadias, G.; Kanoun, M. B.; Goumri-Said, S.; Koutsokeras, L.; Dub, S. N.; Djemia, Ph.

    2014-10-01

    The structure, phase stability, and mechanical properties of ternary alloys of the Zr-Ta-N system are investigated by combining thin-film growth and ab initio calculations. Zr1-xTaxN films with 0≤x≤1 were deposited by reactive magnetron cosputtering in Ar +N2 plasma discharge and their structural properties characterized by x-ray diffraction. We considered both ordered and disordered alloys, using supercells and special quasirandom structure approaches, to account for different possible metal atom distributions on the cation sublattice. Density functional theory within the generalized gradient approximation was employed to calculate the electronic structure as well as predict the evolution of the lattice parameter and key mechanical properties, including single-crystal elastic constants and polycrystalline elastic moduli, of ternary Zr1-xTaxN compounds with cubic rocksalt structure. These calculated values are compared with experimental data from thin-film measurements using Brillouin light scattering and nanoindentation tests. We also study the validity of Vegard's empirical rule and the effect of growth-dependent stresses on the lattice parameter. The thermal stability of these Zr1-xTaxN films is also studied, based on their structural and mechanical response upon vacuum annealing at 850 °C for 3 h. Our findings demonstrate that Zr1-xTaxN alloys with Ta fraction 0.51⩽x⩽0.78 exhibit enhanced toughness, while retaining high hardness ˜30 GPa, as a result of increased valence electron concentration and phase stability tuning. Calculations performed for disordered or ordered structures both lead to the same conclusion regarding the mechanical behavior of these nitride alloys, in agreement with recent literature findings [H. Kindlund, D. G. Sangiovanni, L. Martinez-de-Olcoz, J. Lu, J. Jensen, J. Birch, I. Petrov, J. E. Greene, V. Chirita, and L. Hultman, APL Materials 1, 042104 (2013), 10.1063/1.4822440].

  10. Effect of hydrogen on mechanical properties of -titanium alloys

    Indian Academy of Sciences (India)

    H-J Christ; A Senemmar; M Decker; K Prüßner

    2003-06-01

    Conflicting opinions exist in the literature on the manner in which hydrogen influences the mechanical properties of -titanium alloys. This can be attributed to the -stabilizing effect of hydrogen in these materials leading to major changes in the microstructure as a result of hydrogen charging. The resulting (extrinsic) effect of hydrogen on the mechanical properties can possibly cover up the direct (intrinsic) influences. On the basis of experimentally determined thermodynamic and kinetic data regarding the interaction of hydrogen with -titanium alloys, hydrogen concentrations of up to 8 at.% were established in three commercial alloys by means of hydrogen charging from the gas phase. In order to separate intrinsic and extrinsic effects the charging was carried out during one step of the two-step heat treatment typical of metastable -titanium alloys, while the other step was performed in vacuum. The results on the single-phase condition represent the intrinsic hydrogen effect. Monotonic and cyclic strength increase at the expense of ductility with increasing hydrogen concentration. The brittle to ductile transition temperature shifts to higher values and the fatigue crack propagation threshold value decreases. The microstructure of the metastable, usually two-phase -titanium alloys is strongly affected by hydrogen, although the extent of this effect depends not only on the hydrogen concentration but also on the temperature of charging. This microstructural influence (extrinsic effect) changes the mechanical properties in the opposite direction as compared to the intrinsic hydrogen effect.

  11. Study of Mechanical Properties of AZ91 Magnesium Alloy Welded by Laser Process Taking into Account the Anisotropy Microhardness and Residual Stresses by X-Ray Diffraction

    Science.gov (United States)

    Kouadri, A.; Barrallier, L.

    2011-07-01

    The objective of this investigation was to study the mechanical properties of a magnesium alloy welded by a CO2 laser. Residual stresses were measured by X-ray diffraction. They were calculated by the classic sin2 ψ method in the isotropic zones by using the orientation distribution function (ODF) in the textured zones. The results demonstrated that laser welding results in the formation of several different zones with different microstructural and mechanical properties. Welding principally leads to a reduction in grain size and a new distribution of phases. The most remarkable observation was that of a superficial layer on the surface of the welded zone. This layer has a marked crystallographic texture, a reduction in the level of aluminum, and an elevated microhardness. These characteristics disappear at a depth of 200 μm under the welded zone. These modifications can be explained by the nature of the solidification, which occurs under nonequilibrium conditions resulting in an equiaxial columnar transition. This transition is evident also within the profile of residual tensile stresses, which are at their maximum at the interface between the superficial layer and the rest of the welded zone. These results are explained by the anisotropic properties of the textured layer in relation to the plasticity.

  12. Phase composition, microstructure, and mechanical properties of porous Ti-Nb-Zr alloys prepared by a two-step foaming powder metallurgy method.

    Science.gov (United States)

    Rao, X; Chu, C L; Zheng, Y Y

    2014-06-01

    Porous Ti-Nb-Zr alloys with different porosities from 6.06 to 62.8% are prepared by a two-step foaming powder metallurgy method using TiH2, Nb, and Zr powders together with 0 to 50wt% of NH4HCO3. The effects of the amounts of Nb and Zr as well as the sintering temperature (1473 to 1673K) on their phase composition, porosity, morphology, and mechanical characteristics are investigated. By controlling the porosity, Nb and Zr concentrations as well as the sintering temperature, porous Ti-Nb-Zr alloys with different mechanical properties can be obtained, for example, the hardness between 290 and 63HV, the compressive strength between 1530.5 and 73.4MPa, and the elastic modulus between 10.8 and 1.2GPa. The mechanical properties of the sintered porous Ti-Nb-Zr alloys can be tailored to match different requirements for the human bones and are thus potentially useful in the hard tissue implants.

  13. Thermodynamic properties and solidification kinetics of intermetallic Ni{sub 7}Zr{sub 2} alloy investigated by electrostatic levitation technique and theoretical calculations

    Energy Technology Data Exchange (ETDEWEB)

    Li, L. H.; Hu, L.; Yang, S. J.; Wang, W. L.; Wei, B., E-mail: bbwei@nwpu.edu.cn [Department of Applied Physics, Northwestern Polytechnical University, Xi' an 710072 (China)

    2016-01-21

    The thermodynamic properties, including the density, volume expansion coefficient, ratio of specific heat to emissivity of intermetallic Ni{sub 7}Zr{sub 2} alloy, have been measured using the non-contact electrostatic levitation technique. These properties vary linearly with temperature at solid and liquid states, even down to the obtained maximum undercooling of 317 K. The enthalpy, glass transition, diffusion coefficient, shear viscosity, and surface tension were obtained by using molecular dynamics simulations. Ni{sub 7}Zr{sub 2} has a relatively poor glass forming ability, and the glass transition temperature is determined as 1026 K. The inter-diffusivity of Ni{sub 7}Zr{sub 2} alloy fitted by Vogel–Fulcher–Tammann law yields a fragility parameter of 8.49, which indicates the fragile nature of this alloy. Due to the competition of increased thermodynamic driving force and decreased atomic diffusion, the dendrite growth velocity of Ni{sub 7}Zr{sub 2} compound exhibits double-exponential relationship to the undercooling. The maximum growth velocity is predicted to be 0.45 m s{sup −1} at the undercooling of 335 K. Theoretical analysis reveals that the dendrite growth is a diffusion-controlled process and the atomic diffusion speed is only 2.0 m s{sup −1}.

  14. The influence of initial powder properties on the mechanical alloying process and the final powders structure

    OpenAIRE

    Szymczak, M.; R. Nowosielski; W. Pilarczyk

    2011-01-01

    Purpose: The main aim of this work is to study the influence of initial powder properties on the mechanical alloying process and final powders structure and the production of chosen powder alloy by mechanical alloying method.Design/methodology/approach: The test material was the pure niobium, tin and copper powders. The powders were ground for 2 and 10 hrs. The mechanical alloying process was conducted in a high energy SPEX mill under inert argon atmosphere. The chemical constitution and conc...

  15. Effect of Surface Pretreatment on Adhesive Properties of Aluminum Alloys

    Institute of Scientific and Technical Information of China (English)

    Jinsheng ZHANG; Xuhui ZHAO; Yu ZUO; Jinping XIONG; Xiaofeng ZHANG

    2008-01-01

    The lap-shear strength and durability of adhesive bonded AI alloy joints with different pretreatments were studied by the lap-shear test and wedge test. The results indicate that the maximum lap-shear strength and durability of the bonding joints pretreated by different processes are influenced by the grade of abrasive papers and can be obviously improved by phosphoric acid anodizing. Alkali etching can obviously improve the durability of bonding joints although it slightly influences the maximum lap-shear strength. The process which is composed of grit-finishing, acetone degreasing, alkali etching and phosphoric acid anodizing, provides a better adhesive bonding property of AI alloy.

  16. Influence of vacuum hot-pressing temperature on the microstructure and mechanical properties of Ti–3Al–2.5V alloy obtained by blended elemental and master alloy addition powders

    International Nuclear Information System (INIS)

    This study addresses the processing of near-net-shape, chemically homogeneous and fine-grained Ti–3Al–2.5V components using vacuum hot-pressing. Two Ti–3Al–2.5V starting powders were considered. On one side, hydride–dehydride (HDH) elemental titanium was blended with an HDH Ti–6Al–4V prealloyed powder. On the other side, an Al:V master alloy was added to the HDH elemental titanium powder. The powders were processed applying a uniaxial pressure of 30 MPa. The sintering temperatures studied varied between 900 °C and 1300 °C. The relative density of the samples increased with processing temperature and almost fully dense materials were obtained. The increase of the sintering temperature led also to a strong reaction between the titanium powders and the processing tools. This phenomenon occurred particularly with boron nitride (BN) coating, which was used to prevent the direct contact between titanium and graphite tools. The flexural properties of the Ti–3Al–2.5V samples increased with vacuum hot-pressing temperature and are comparable to those specified for wrought titanium medical devices. Therefore, the produced materials are promising candidates for load bearing applications as implant materials. -- Highlights: ► Almost fully dense Ti–3Al–2.5V alloy components are obtained by means of hot-pressing. ► The bending properties of the Ti–3Al–2.5V alloy are studied in details. ► The reaction that occurs between the Ti–3Al–2.5V powder and the BN coating is analysed. ► Microstructural evolution of blending elemental and master alloy materials with the temperature.

  17. Mechanical properties of hot rolled 2519 aluminum alloy plate

    Institute of Scientific and Technical Information of China (English)

    彭大暑; 陈险峰; 林启权; 张辉

    2003-01-01

    The effects of differences of temper on mechanical properties of T6, T7 and T8 plates of aluminum alloy 2519 were studied. The stress corrosion cracking(SCC) sensitivity was evaluated with parameters such as Kσ and Kδ.Tensile tests were divided into two groups: one was performed on tensile specimens without pre-corrosion, the other was performed on tensile specimens which were pre-corroded in 3.5%NaCl+1%H2O2 solution at 25 ℃.The results show that SCC resistance of alloy 2519 ranks in the order of T8>T7>T6 and the mechanical properties rank in the order of T6>T8>T7. SEM fractographs of the failed specimen show that the SCC sensitivity can be determined by the distribution of the second phase particles and size and the shape of grains in the alloy.

  18. ESTIMATION OF LOCAL HYSTERETIC PROPERTIES FOR SHAPE MEMORY ALLOYS

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The applicability of shape memory alloys (SMAs) in structural dynamics, particularly as hysteretic damping elements, is limited by the difficulties in modelling their deformation characteristics. At typical engineering design levels of loading SMAs exhibit pseudo-elastic properties. A combined experimental and simulation approach suitable for the characterisation of novel smart devices based on the pseudo-elastic effect is described.

  19. Microstructure and magnetic properties of nanostructured (Fe{sub 0.8}Al{sub 0.2}){sub 100–x}Si{sub x} alloy produced by mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Boukherroub, N. [UR-MPE, M' hamed Bougara University, Boumerdes 35000 (Algeria); Guittoum, A., E-mail: aguittoum@gmail.com [Nuclear Research Centre of Algiers, 02 Bd Frantz Fanon, BP 399 Alger-Gare, Algiers (Algeria); Laggoun, A. [UR-MPE, M' hamed Bougara University, Boumerdes 35000 (Algeria); Hemmous, M. [Nuclear Research Centre of Algiers, 02 Bd Frantz Fanon, BP 399 Alger-Gare, Algiers (Algeria); Martínez-Blanco, D. [SCTs, University of Oviedo, EPM, 33600 Mieres (Spain); Blanco, J.A. [Department of Physics, University of Oviedo, Calvo Sotelo St., 33007 Oviedo (Spain); Souami, N. [Nuclear Research Centre of Algiers, 02 Bd Frantz Fanon, BP 399 Alger-Gare, Algiers (Algeria); Gorria, P. [Department of Physics and IUTA, EPI, University of Oviedo, 33203 Gijón (Spain); Bourzami, A. [Laboratoire d' Etudes des Surfaces et Interfaces des Matériaux Solides (LESIMS), Université Sétif1, 19000 Sétif (Algeria); Lenoble, O. [Institut Jean Lamour, CNRS-Université de Lorraine, Boulevard des aiguillettes, BP 70239, F-54506 Vandoeuvre lès Nancy (France)

    2015-07-01

    We report on how the microstructure and the silicon content of nanocrystalline ternary (Fe{sub 0.8}Al{sub 0.2}){sub 100–x}Si{sub x} powders (x=0, 5, 10, 15 and 20 at%) elaborated by high energy ball milling affect the magnetic properties of these alloys. The formation of a single-phase alloy with body centred cubic (bcc) crystal structure is completed after 72 h of milling time for all the compositions. This bcc phase is in fact a disordered Fe(Al,Si) solid solution with a lattice parameter that reduces its value almost linearly as the Si content is increased, from about 2.9 Å in the binary Fe{sub 80}Al{sub 20} alloy to 2.85 Å in the powder with x=20. The average nanocrystalline grain size also decreases linearly down to 10 nm for x=20, being roughly half of the value for the binary alloy, while the microstrain is somewhat enlarged. Mössbauer spectra show a sextet thus suggesting that the disordered Fe(Al,Si) solid solution is ferromagnetic at room temperature. However, the average hyperfine field diminishes from 27 T (x=0) to 16 T (x=20), and a paramagnetic doublet is observed for the powders with higher Si content. These results together with the evolution of both the saturation magnetization and the coercive field are discussed in terms of intrinsic and extrinsic properties. - Highlights: • Single-phase nanocrystalline (Fe{sub 0.8}Al{sub 0.2}){sub 100–x}Si{sub x} (x=0, 5, 10, 15 and 20 at%) powders were successfully fabricated by mechanical alloying for a milling time of 72 h. • The insertion of Si atoms leads to a unit-cell contraction and a decrease in the average crystallite size. • The hyperfine and magnetic properties of (Fe{sub 0.8}Al{sub 0.2}){sub 100–x}Si{sub x} were influenced by the Si content.

  20. The influence of chemical composition on the properties and structure Al-Si-Cu(Mg) alloys

    OpenAIRE

    M. Kaczorowski; A. Krzyńska

    2007-01-01

    The mechanical properties of different chemical composition AlSiCuMg type cast alloys after precipitation hardening are presented. The aim of the study was to find out how much the changes in chemistry of aluminum cast alloys permissible by EN-PN standards may influence the mechanical properties of these alloys. Eight AlSi5Cu3(Mg) type cast alloys of different content alloying elements were selected for the study. The specimens cut form test castings were subjected to precipitation hardening ...

  1. Tribology properties of composite layer of CrMoCu alloy cast iron by combined treatment of ion nitrocarburizing and sulphurizing

    Institute of Scientific and Technical Information of China (English)

    MA Shi-ning; HU Chun-hua; LI Xin; QIU Ji

    2004-01-01

    Composite layer with nitrocarbonide and sulfide was made on the surface of CrMoCu alloy cast iron by combined treatment of ion nitrocarburizing and sulphurizing. The composite layer is composed of sulfide layer, nitrocarbonide hypo-surface layer and its diffusing layer, the size of sulfide globular grains distributing equably on the surface is in nano-micron-scale, and the phase structure of the composite layer is composed of FeS, FeS1-x, Fe2C and Fe3N. Under oil lubrication, sulphurized surface shows good scuffing-resistance only under low velocity, and nitrocarburized and sulphurized surface greatly improves the scuffing-resistance and wear-resistance of CrMoCu alloy cast iron, its integrated friction and wear properties are better than those of the plain and sulphurized surfaces under all the velocities.

  2. The effect of location on the microstructure and mechanical properties of titanium aluminides produced by additive layer manufacturing using in-situ alloying and gas tungsten arc welding

    International Nuclear Information System (INIS)

    An innovative and low cost additive layer manufacturing (ALM) process is used to produce γ-TiAl based alloy wall components. Gas tungsten arc welding (GTAW) provides the heat source for this new approach, combined with in-situ alloying through separate feeding of commercially pure Ti and Al wires into the weld pool. This paper investigates the morphology, microstructure and mechanical properties of the additively manufactured TiAl material, and how these are affected by the location within the manufactured component. The typical additively layer manufactured morphology exhibits epitaxial growth of columnar grains and several layer bands. The fabricated γ-TiAl based alloy consists of comparatively large α2 grains in the near-substrate region, fully lamellar colonies with various sizes and interdendritic γ structure in the intermediate layer bands, followed by fine dendrites and interdendritic γ phases in the top region. Microhardness measurements and tensile testing results indicated relatively homogeneous mechanical characteristics throughout the deposited material. The exception to this homogeneity occurs in the near-substrate region immediately adjacent to the pure Ti substrate used in these experiments, where the alloying process is not as well controlled as in the higher regions. The tensile properties are also different for the vertical (build) direction and horizontal (travel) direction because of the differing microstructure in each direction. The microstructure variation and strengthening mechanisms resulting from the new manufacturing approach are analysed in detail. The results demonstrate the potential to produce full density titanium aluminide components directly using the new additive layer manufacturing method

  3. The crystallization and properties of alloys with Fe partly substituted by Cr and Cu fully substituted by Au in Finemet

    International Nuclear Information System (INIS)

    The structure, crystallization and magnetic properties of ribbons obtained by first making amorphous ribbons and then objecting them to a crystallization annealing have been published elsewhere by us previously. In the present work the soft magnetic ribbons Fe73.5-xCr xSi13.5B9Nb3Au1 (numbers indicate at.%, x = 1-5) are prepared by fast quenching on a single copper wheel. X-ray diffraction patterns show that the as-cast samples are amorphous. Differential scanning calorimetry analysis indicates that the crystallization temperature of the α-Fe(Si) phase is a little higher than that of pure Finemet. With the same annealing conditions, the crystallization volume fraction decreases with increasing Cr content substituted for Fe. Hysteresis loops of as-cast samples measured by Permagraph show that domain walls are pinned. After appropriate annealing, the ultrasoft magnetic properties of nanocomposite materials are established. The magnetic entropy change, vertical bar ΔS m vertical bar, of studied samples has been determined, and a giant magnetocaloric effect is found. Our materials could be considered as promising magnetic refrigerants working at high temperatures (several hundreds deg. C)

  4. Electrochemical and Optical Properties of Magnesium-Alloy Hydrides Reviewed

    Directory of Open Access Journals (Sweden)

    Thirugnasambandam G. Manivasagam

    2012-10-01

    Full Text Available As potential hydrogen storage media, magnesium based hydrides have been systematically studied in order to improve reversibility, storage capacity, kinetics and thermodynamics. The present article deals with the electrochemical and optical properties of Mg alloy hydrides. Electrochemical hydrogenation, compared to conventional gas phase hydrogen loading, provides precise control with only moderate reaction conditions. Interestingly, the alloy composition determines the crystallographic nature of the metal-hydride: a structural change is induced from rutile to fluorite at 80 at.% of Mg in Mg-TM alloy, with ensuing improved hydrogen mobility and storage capacity. So far, 6 wt.% (equivalent to 1600 mAh/g of reversibly stored hydrogen in MgyTM(1-yHx (TM: Sc, Ti has been reported. Thin film forms of these metal-hydrides reveal interesting electrochromic properties as a function of hydrogen content. Optical switching occurs during (dehydrogenation between the reflective metal and the transparent metal hydride states. The chronological sequence of the optical improvements in optically active metal hydrides starts with the rare earth systems (YHx, followed by Mg rare earth alloy hydrides (MgyGd(1-yHx and concludes with Mg transition metal hydrides (MgyTM(1-yHx. In-situ optical characterization of gradient thin films during (dehydrogenation, denoted as hydrogenography, enables the monitoring of alloy composition gradients simultaneously.

  5. Microstructures and mechanical properties of magnesium alloy and stainless steel weld-joint made by friction stir lap welding

    International Nuclear Information System (INIS)

    Highlights: → Friction stir lap welding technology with cutting pin was successfully employed to form lap joint of magnesium and steel. → The cutting pin made the lower steel participate in deformation and the interface was no longer flat. → A saw-toothed structure formed due to a mechanical mixing of the magnesium and steel was found at the interface. → A high-strength joint was produced which fractured in the magnesium side. -- Abstract: Friction stir lap welding was conducted on soft/hard metals. A welding tool was designed with a cutting pin of rotary burr made of tungsten carbide, which makes the stirring pin possible to penetrate and cut the surface layer of the hard metal. Magnesium alloy AZ31 and stainless steel SUS302 were chosen as soft/hard base metals. The structures of the joining interface were analyzed by scanning electron microscopy (SEM). The joining strength was evaluated by tensile shear test. The results showed that flower-like interfacial morphologies were presented with steel flashes and scraps, which formed bonding mechanisms of nail effect by long steel flashes, zipper effect by saw-tooth structure and metallurgical bonding. The shear strength of the lap joint falls around the shear strength of butt joint of friction stir welded magnesium alloy.

  6. Structure and magnetic properties of Fe-based amorphous alloys

    Directory of Open Access Journals (Sweden)

    K. Błoch

    2013-12-01

    Full Text Available Purpose: This paper presents studies relating to the structure, magnetic properties and thermal stability of the following bulk amorphous alloys: Fe61Co10Ti3-xY6+xB20 (where x = 0 or 1 Design/methodology/approach: The investigated samples were prepared in the form of rods by using the suction-casting method. The material structures were investigated using X-ray diffractometry and Mössbauer spectroscopy. The thermal stability was determined on the basis of Differential Scanning Calorimetry (DSC plots The magnetic properties were studied using a completely automated set up for measuring susceptibility and its disaccommodation. Findings: It was found that both alloys were amorphous in the as-cast state. The DSC curve obtained for Fe61Co10Ti2Y7B20 alloy exhibited one exothermic peak, while for the Fe61Co10Ti3Y6B20 sample, two peaks were distinguishable, corresponding to the crystallization of the sample. The bifurcation of the maximum on the DSC curve for the Fe61Co10Ti3Y6B20 sample may also testify to the presence of the primary crystallizing phase (FeCo23B6 [1,2]. Data obtained from the analysis of the magnetic susceptibility disaccommodation curves clearly show that in the Fe61Co10Ti3Y6B20 alloy there is less free volumes than in the second of the investigated alloys, this results in a lesser range of relaxation time. Moreover, Fe61Co10Ti3Y6B20 alloy exhibits the better time and thermal stability of magnetic properties In both of the studied alloys, at low frequencies, the total losses were comparable with those observed in classical silicon-iron alloys. Practical implications: A Ferrometer was used for the determination of core losses. Originality/value: The paper presents some researches of the Fe-based bulk amorphous alloys obtained by the suction-casting method.

  7. Effects of single pulse energy on the properties of ceramic coating prepared by micro-arc oxidation on Ti alloy

    Science.gov (United States)

    Wang, Jun-Hua; Wang, Jin; Lu, Yan; Du, Mao-Hua; Han, Fu-Zhu

    2015-01-01

    The effects of single pulse energy on the properties of ceramic coating fabricated on a Ti-6Al-4V alloy via micro-arc oxidation (MAO) in aqueous solutions containing aluminate, phosphate, and some additives are investigated. The thickness, micro-hardness, surface and cross-sectional morphology, surface roughness, and compositions of the ceramic coating are studied using eddy current thickness meter, micro-hardness tester, JB-4C Precision Surface roughness meter, scanning electron microscopy (SEM) and X-ray diffraction (XRD). Single pulse energy remarkably influences the ceramic coating properties. The accumulative time of impulse width is an important parameter in the scientific and rational measurement of the film forming law of ceramic coating. The ceramic coating thickness approximately linearly increases with the cumulative time of impulse width. Larger impulse width resulted in higher single pulse energy, film forming rates and thicker ceramic coating thickness. The sizes of oxide particles, micro-pores and micro-cracks slightly increase with impulse width and single pulse energy. The main surface conversion products generated during MAO process in aqueous solutions containing aluminate are rutile TiO2, anatase TiO2, and a large amount of Al2TiO5. The effects of single pulse energy on the micro-hardness and phase composition of ceramic coating are not as evident as those of frequency and duty cycle.

  8. Properties of amorphous FeCoB alloy particles (abstract)

    DEFF Research Database (Denmark)

    Charles, S. W.; Wells, S.; Meagher, A.;

    1988-01-01

    Amorphous and crystalline alloy particles (0.05–0.5 nm) of FexCoyBz in which the ratio x:y ranges from 0 to 1 have been prepared by the borohydride reduction of iron and cobalt salts in aqueous solution. The structure of the particles has been studied using Mössbauer spectroscopy and x....... 1). It has been shown that the fraction of boron in the alloys (10–35 at. %) is dependent upon the rate of addition of salts to borohydride and the concentration of cobalt present; this in turn influences the crystallinity and magnetic properties . Journal of Applied Physics is copyrighted...

  9. Property Criteria for Automotive Al-Mg-Si Sheet Alloys

    OpenAIRE

    Ramona Prillhofer; Gunther Rank; Josef Berneder; Helmut Antrekowitsch; Uggowitzer, Peter J.; Stefan Pogatscher

    2014-01-01

    In this study, property criteria for automotive Al-Mg-Si sheet alloys are outlined and investigated in the context of commercial alloys AA6016, AA6005A, AA6063 and AA6013. The parameters crucial to predicting forming behavior were determined by tensile tests, bending tests, cross-die tests, hole-expansion tests and forming limit curve analysis in the pre-aged temper after various storage periods following sheet production. Roping tests were performed to evaluate surface quality, for the deplo...

  10. Effect of Sc{sub 2}O{sub 3} particles on the microstructure and properties of tungsten alloy prepared by spark plasma sintering

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Hong-Yu [School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); Luo, Lai-Ma, E-mail: luolaima@126.com [School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); National–Local Joint Engineering Research Centre of Nonferrous Metals and Processing Technology, Hefei 230009 (China); Chen, Jing-Bo [School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); Li, Ping [School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); National–Local Joint Engineering Research Centre of Nonferrous Metals and Processing Technology, Hefei 230009 (China); Luo, Guang-Nan [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Cheng, Ji-Gui [School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); National–Local Joint Engineering Research Centre of Nonferrous Metals and Processing Technology, Hefei 230009 (China); Wu, Yu-Cheng, E-mail: ycwu@hfut.edu.cn [School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); National–Local Joint Engineering Research Centre of Nonferrous Metals and Processing Technology, Hefei 230009 (China)

    2015-07-15

    Highlights: • Effect of Sc{sub 2}O{sub 3} on microstructure and properties of tungsten alloy were studied. • Sc{sub 2}O{sub 3} significantly refined the grain size and increased the density of tungsten alloy. • The tensile strength values of the W–2 vol%Sc{sub 2}O{sub 3} samples were higher than the others. - Abstract: W–Sc{sub 2}O{sub 3} composite powders (W, W–0.5 vol%Sc{sub 2}O{sub 3}, and W–2 vol%Sc{sub 2}O{sub 3}) doped with highly uniform Sc{sub 2}O{sub 3} particles were successfully synthesized by mechanical alloying followed by hydrogen reduction with Sc{sub 2}O{sub 3} and WO{sub 3} powders. The reduced powders were then consolidated by spark plasma sintering at 1700 °C to suppress grain growth during sintering. Field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, and high-resolution transmission electron microscopy analyses, as well as tensile tests and thermal conductivity measurements, were used to characterize the samples. The results showed that the Sc{sub 2}O{sub 3} particles were uniformly distributed in the tungsten grains and grain boundaries. The W–2vol%Sc{sub 2}O{sub 3} composite possess the best relative density and Vickers micro-hardness up to 98.6% and 683.2 Hv, respectively. The Sc{sub 2}O{sub 3} particles significantly refine the grain size and increase the density of tungsten alloy. With increased Sc{sub 2}O{sub 3} content, the thermal conductivity decreased while tensile strength of the samples respectively increased at 700 and 800 °C.

  11. Increasing of founding properties of secondary aluminium alloys

    Directory of Open Access Journals (Sweden)

    O.V. Lyutova

    2013-06-01

    Full Text Available Purpose. To study the influence of metallurgical factors of production on casting properties of secondary aluminum alloy АК9М2. Methodology. For the experimental melts shaving amount in a charge, iron content and the quantity of modifier additive were chosen as independent variables. The components of modifier were being changed in the intervals of 25…40 % Na2CO3, 12…20 % SiC, 3…8 % Ti, the other – S. The microstructure of alloys was investigated under a light microscope, using the method of quantitative metallography. Influence analysis of certain parameters of alloys was conducted by mathematical statistics methods. The influence of shaving additions, iron and modifier amount on liquidity and porosity of the resulting alloys was studied. Findings. The paper shows that the increase of shaving content in the charge from 1 to 19 % and iron content in alloy from 0.66 to 2.34 % resulted in the decline of alloy liquidity on 30…35 %. Simultaneously the linear shrinkage reduction for 18…20 % and the porosity increase from 0.5 to 2.5 points were observed. The presented changes of alloy casting properties are conditioned by the amount of intermetallic phases of unfavorable form and its capacity for aeration. Increase of modifier additive from 0.02 to 0.15 % resulted in the liquidity increase on 10…15 %, the increase of linear shrinkage on 30…35 % and porosity decline from 2.5 to 0.5 points. At the same time a change of form of intermetallic phases and increase of their evenness were observed. Originality. The increase of iron concentration in silumin composition is accompanied by the decline of its liquidity. Thus, the rate of decline of alloy liquidity is proportional to the amount of dissolved iron. The character of iron influence is caused by formation of high temperature intermetallic compounds of the type Al3Fe, Al5SiFe, which promote the metal viscidity. Practical value. Practical use of the obtained scientific results would

  12. Microstructures and properties of aluminum die casting alloys

    Energy Technology Data Exchange (ETDEWEB)

    M. M. Makhlouf; D. Apelian; L. Wang

    1998-10-01

    This document provides descriptions of the microstructure of different aluminum die casting alloys and to relate the various microstructures to the alloy chemistry. It relates the microstructures of the alloys to their main engineering properties such as ultimate tensile strength, yield strength, elongation, fatigue life, impact resistance, wear resistance, hardness, thermal conductivity and electrical conductivity. Finally, it serves as a reference source for aluminum die casting alloys.

  13. Synthesis and Magnetic Properties of Nanoparticles of Fe-Co Alloys and Their Oxides Prepared by Chemical Vapor Condensation

    Institute of Scientific and Technical Information of China (English)

    Zhenhua WANG; Zhidong ZHANG; C.J. Choi; B.K. Kim; J.C. Kim

    2004-01-01

    Nanoparticles of Fe-Co alloys and their oxides with the particle size below 20 nm were prepared by chemical vapor condensation process. The pure Ar, Ar+1%O2, Ar+3%O2 and Ar+6%O2 were used as carrier gases, with iron carbonyl and cobalt carbonyl as the precursors. XRD patterns showed that Fe-Co metallic nanoparticles were synthesized by using pure Ar as carrier gas,and only metal oxides were obtained using Ar+(>3)%O2 as carrier gas. The HRTEM images and TG-DTA curves were used to study the core-shell structure of the different nanoparticles. The nanoparticles obtained in pure Ar consist of black core and light shell with thickness of 2~4 nm. However, in the particles obtained in Ar+6%O2, the oxides core with visible lattice fringes are surrounded by thin shell.

  14. Relationship between silver concentration with microstructural and mechanical properties of rolled AlZn alloy

    International Nuclear Information System (INIS)

    The relationship of Ag addition on microstructural and mechanical properties of rolled AlZn alloy was investigated. AlZn alloys were prepared by metal mould casting method and the Ag addition was done by Vortex technique. Microstructural characterization of AlZnAg specimens was analyzed by means of X-ray diffraction, scanning electron microscopy and transmission electron microscopy. Results show that the phases of the as-cast state alloy are solid solution zinc-rich hexagonal close-packed (hcp) crystal structure, named η-phase and α-Al solid solution with Zn dissolved into the matrix. The silver concentration in AlZn alloy influences the volume of AgZn3 precipitates. The mechanical properties, especially the flow stress and elongation of the alloy were improved by the Ag addition. The Vortex method was used in order to diminish the process cost, generating an alloy with homogenous microstructure, less casting porosity and better mechanical properties.

  15. Static and Vibrational Properties of Lithium Alloys

    Directory of Open Access Journals (Sweden)

    Aditya M. Vora

    2011-01-01

    Full Text Available The computations of the static and vibrational properties of four equiatomic lithium alloys viz. Li0.5Na0.5, Li0.5K0.5, Li0.5Rb0.5 and Li0.5Cs0.5 to second order in local model potential is discussed in terms of real-space sum of Born von Karman central force constants. The local field correlation functions due to Hartree (H, Ichimaru-Utsumi (IU and Sarkar et al. (S are used to investigate influence of the screening effects on the aforesaid properties. Results for the lattice constants i.e.С11, С12, С44, С12 – С44, С12/С44 and bulk modulus Å obtained using the Hartree (H local field correction function has higher values in comparison with the results obtained for the same properties using Ichimaru-Utsumi (IU and Sarkar et al. (S local field correction functions. The results for the Shear modulus (С′, deviation from Cauchy’s relation, Poisson’s ratio σ, Young modulus Y, propagation velocity of elastic waves, phonon dispel-rsion curves and degree of anisotropy A are highly appreciable for the four lithium alloys.

  16. Properties of thermally stable PM Al-Cr based alloy

    International Nuclear Information System (INIS)

    The presented paper describes properties of Al-6.0 wt.%Cr-2.3 wt.%Fe-0.4 wt.%Ti-0.7 wt.%Si alloy produced by powder metallurgy (PM). The powder alloy was prepared by the pressure nitrogen melt atomization. The granulometric powder fraction of less than 45 μm was then hot-extruded at 450 deg. C to produce a rod of 6 mm in diameter. Microstructure of the as-extruded material was composed of recrystallized α(Al) grains (the average grain size of 640 nm) and Al13Cr2 spheroids (the average particle diameter of 130 nm and interparticle spacing of 290 nm). Metastable phases were not observed due to their decomposition on the hot extrusion. Hardness of the as-extruded material was 108 HV1, ultimate tensile strength, 327 MPa, yield strength, 258 MPa and elongation, 14%. Mechanical properties resulted mainly from Hall-Petch strengthening. The room-temperature mechanical properties were also measured after a long-term annealing at 400 deg. C. The investigated PM material was compared with the commercial Al-11.8 wt.%Si-0.9 wt.%Ni-1.2 wt.%Cu-1.2 wt.%Mg casting alloy generally applied at elevated temperatures. The PM alloy showed much higher thermal stability, since its room temperature hardness and tensile properties did not degradate significantly even after annealing at 400 deg. C/200 h. In contrast, the hardness and strength of the casting alloy reduced rapidly already after a 30 min annealing. The excellent thermal stability of the investigated PM material was a consequence of very slow diffusivities and low equilibrium solubilities of chromium and iron in solid aluminium

  17. Properties of thermally stable PM Al-Cr based alloy

    Energy Technology Data Exchange (ETDEWEB)

    Vojtech, D. [Department of Metals and Corrosion Engineering, Institute of Chemical Technology, Prague, Technicka 5, 166 28 Prague 6 (Czech Republic)], E-mail: Dalibor.Vojtech@vscht.cz; Verner, J. [Department of Metals and Corrosion Engineering, Institute of Chemical Technology, Prague, Technicka 5, 166 28 Prague 6 (Czech Republic); Serak, J. [Department of Metals and Corrosion Engineering, Institute of Chemical Technology, Prague, Technicka 5, 166 28 Prague 6 (Czech Republic); Simancik, F. [Institute of Materials and Machine Mechanics, Slovak Academy of Sciences, Racianska 75, 831 02 Bratislava 3 (Slovakia); Balog, M. [Institute of Materials and Machine Mechanics, Slovak Academy of Sciences, Racianska 75, 831 02 Bratislava 3 (Slovakia); Nagy, J. [Institute of Materials and Machine Mechanics, Slovak Academy of Sciences, Racianska 75, 831 02 Bratislava 3 (Slovakia)

    2007-06-15

    The presented paper describes properties of Al-6.0 wt.%Cr-2.3 wt.%Fe-0.4 wt.%Ti-0.7 wt.%Si alloy produced by powder metallurgy (PM). The powder alloy was prepared by the pressure nitrogen melt atomization. The granulometric powder fraction of less than 45 {mu}m was then hot-extruded at 450 deg. C to produce a rod of 6 mm in diameter. Microstructure of the as-extruded material was composed of recrystallized {alpha}(Al) grains (the average grain size of 640 nm) and Al{sub 13}Cr{sub 2} spheroids (the average particle diameter of 130 nm and interparticle spacing of 290 nm). Metastable phases were not observed due to their decomposition on the hot extrusion. Hardness of the as-extruded material was 108 HV1, ultimate tensile strength, 327 MPa, yield strength, 258 MPa and elongation, 14%. Mechanical properties resulted mainly from Hall-Petch strengthening. The room-temperature mechanical properties were also measured after a long-term annealing at 400 deg. C. The investigated PM material was compared with the commercial Al-11.8 wt.%Si-0.9 wt.%Ni-1.2 wt.%Cu-1.2 wt.%Mg casting alloy generally applied at elevated temperatures. The PM alloy showed much higher thermal stability, since its room temperature hardness and tensile properties did not degradate significantly even after annealing at 400 deg. C/200 h. In contrast, the hardness and strength of the casting alloy reduced rapidly already after a 30 min annealing. The excellent thermal stability of the investigated PM material was a consequence of very slow diffusivities and low equilibrium solubilities of chromium and iron in solid aluminium.

  18. Study on preparation and properties of molybdenum alloys reinforced by nano-sized ZrO{sub 2} particles

    Energy Technology Data Exchange (ETDEWEB)

    Cui, Chaopeng; Gao, Yimin; Zhou, Yucheng [Xi' an Jiaotong University, State Key Laboratory for Mechanical Behavior of Materials, Xi' an, Shaanxi Province (China); Wei, Shizhong [Henan University of Science and Technology, School of Materials Science and Engineering, Luoyang (China); Henan University of Science and Technology, Engineering Research Center of Tribology and Materials Protection, Ministry of Education, Luoyang (China); Zhang, Guoshang; Zhu, Xiangwei; Guo, Songliang [Henan University of Science and Technology, School of Materials Science and Engineering, Luoyang (China)

    2016-03-15

    The nano-sized ZrO{sub 2}-reinforced Mo alloy was prepared by a hydrothermal method and a subsequent powder metallurgy process. During the hydrothermal process, the nano-sized ZrO{sub 2} particles were added into the Mo powder via the hydrothermal synthesis. The grain size of Mo powder decreases obviously with the addition of ZrO{sub 2} particles, and the fine-grain sintered structure is obtained correspondingly due to hereditation. In addition to a few of nano-sized ZrO{sub 2} particles in grain boundaries or sub-boundaries, most are dispersed in grains. The tensile strength and yield strength have been increased by 32.33 and 53.76 %. (orig.)

  19. Study on preparation and properties of molybdenum alloys reinforced by nano-sized ZrO2 particles

    International Nuclear Information System (INIS)

    The nano-sized ZrO2-reinforced Mo alloy was prepared by a hydrothermal method and a subsequent powder metallurgy process. During the hydrothermal process, the nano-sized ZrO2 particles were added into the Mo powder via the hydrothermal synthesis. The grain size of Mo powder decreases obviously with the addition of ZrO2 particles, and the fine-grain sintered structure is obtained correspondingly due to hereditation. In addition to a few of nano-sized ZrO2 particles in grain boundaries or sub-boundaries, most are dispersed in grains. The tensile strength and yield strength have been increased by 32.33 and 53.76 %. (orig.)

  20. Study on preparation and properties of molybdenum alloys reinforced by nano-sized ZrO2 particles

    Science.gov (United States)

    Cui, Chaopeng; Gao, Yimin; Wei, Shizhong; Zhang, Guoshang; Zhou, Yucheng; Zhu, Xiangwei; Guo, Songliang

    2016-03-01

    The nano-sized ZrO2-reinforced Mo alloy was prepared by a hydrothermal method and a subsequent powder metallurgy process. During the hydrothermal process, the nano-sized ZrO2 particles were added into the Mo powder via the hydrothermal synthesis. The grain size of Mo powder decreases obviously with the addition of ZrO2 particles, and the fine-grain sintered structure is obtained correspondingly due to hereditation. In addition to a few of nano-sized ZrO2 particles in grain boundaries or sub-boundaries, most are dispersed in grains. The tensile strength and yield strength have been increased by 32.33 and 53.76 %.

  1. The Effect of Post-Bond Heat Treatment on Tensile Property of Diffusion Bonded Austenitic Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Sunghoon; Kim, Sung Kwan; Jang, Changheui [KAIST, Daejeon (Korea, Republic of); Sah, Injin [KAERI, Daejeon (Korea, Republic of)

    2015-12-15

    Diffusion bonding is the key manufacturing process for the micro-channel type heat exchangers. In this study, austenitic alloys such as Alloy 800HT, Alloy 690, and Alloy 600, were diffusion bonded at various temperatures and the tensile properties were measured up to 650 ℃. Tensile ductility of diffusion bonded Alloy 800HT was significantly lower than that of base metal at all test temperatures. While, for Alloy 690 and Alloy 600, tensile ductility of diffusion bonded specimens was comparable to that of base metals up to 500 ℃, above which the ductility became lower. The poor ductility of diffusion bonded specimen could have caused by the incomplete grain boundary migration and precipitates along the bond-line. Application of post-bond heat treatment (PBHT) improved the ductility close to that of base metals up to 550 ℃. Changes in tensile properties were discussed in view of the microstructure in the diffusionbonded area.

  2. Microstructure and properties of new Mg-Li-Zn wrought alloys

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Cold-rolling workability, heat treatment characteristics and mechanical properties of Mg-5%-22 % Li-2 % Zn(mass fraction) wrought alloys were studied. Density of alloys is between 1.19 and 1.62 g/cm3. The limit of reduction for cold rolling of the β phase alloys at 16% and 22%Li exceeds 90% at room temperature. The properties and microstructures of Mg-Li-Zn alloys were studied, which were homogenized, cold rolled, then annealed at different temperatures. Recrystallization behaviors of the alloys were investigated through microstructures observing and hardness measuring. The results show that the cast billets are suitable for rolling after homogenization at 573K for 12 h for Mg-9Li-2Zn-2Ca alloy and at 523K for 24 h for Mg-9Li-2Zn-2Ca alloy. The cold rolled plates were completely recrystallizated by annealing at 573K for 1 h.

  3. Analysis Of Transport Properties of Mechanically Alloyed Lead Tin Telluride

    Science.gov (United States)

    Krishna, Rajalakshmi

    The work described in this thesis had two objectives. The first objective was to develop a physically based computational model that could be used to predict the electronic conductivity, Seebeck coefficient, and thermal conductivity of Pb1-xSnxTe alloys over the 400 K to 700 K temperature as a function of Sn content and doping level. The second objective was to determine how the secondary phase inclusions observed in Pb1-xSn xTe alloys made by consolidating mechanically alloyed elemental powders impact the ability of the material to harvest waste heat and generate electricity in the 400 K to 700 K temperature range. The motivation for this work was that though the promise of this alloy as an unusually efficient thermoelectric power generator material in the 400 K to 700 K range had been demonstrated in the literature, methods to reproducibly control and subsequently optimize the materials thermoelectric figure of merit remain elusive. Mechanical alloying, though not typically used to fabricate these alloys, is a potential method for cost-effectively engineering these properties. Given that there are deviations from crystalline perfection in mechanically alloyed material such as secondary phase inclusions, the question arises as to whether these defects are detrimental to thermoelectric function or alternatively, whether they enhance thermoelectric function of the alloy. The hypothesis formed at the onset of this work was that the small secondary phase SnO2inclusions observed to be present in the mechanically alloyed Pb1-xSnxTe would increase the thermoelectric figure of merit of the material over the temperature range of interest. It was proposed that the increase in the figure of merit would arise because the inclusions in the material would not reduce the electrical conductivity to as great an extent as the thermal conductivity. If this were to be true, then the experimentally measured electronic conductivity in mechanically alloyed Pb1-xSnxTe alloys that have

  4. Structural and mechanical properties of 7075 alloy strips fabricated by roll-casting in a static magnetic field

    Institute of Scientific and Technical Information of China (English)

    Xin Su; Guang-ming Xu; Jiu-wen Jiang

    2014-01-01

    The influences of a 0.2 T static magnetic field on the microstructure of 7075 aluminum alloys sheets produced with a twin-roll continuous caster at 675°C were investigated in this paper. Under a uniform magnetic field, the primary dendrites were refined and tended to be equiaxed. The microstructure consisted of an intermediate case between dendritic and equiaxed grains. Moreover, the use of an external static field in the twin-roll casting process can reduce heat discharge, resulting in a decrease in undercooling, and may also account for the abatement of segregation bands. In addition, the static magnetic field effectively improved the solute mixing capacity, and the added atoms more easily diffused from precipitates to theα-Al matrix, which resulted in an increase in the mechanical properties of the rolled sheets. Specimens prepared both in the presence of a static magnetic field and in the absence of a static magnetic field exhibited brittle-fracture characteristics.

  5. Influence of pH and bath composition on properties of Ni–Fe alloy films synthesized by electrodeposition

    Indian Academy of Sciences (India)

    Xinghua Su; Chengwen Qiang

    2012-04-01

    Fe–Ni films were electrodeposited on ITO glass substrates from the electrolytes with different molar ratio of Ni2+/Fe2+ and different pH values (2.1, 2.9, 3.7 and 4.3) at 25°C. The properties of Fe–Ni alloy films depend on both Ni2+ and Fe2+ concentrations in electrolyte and pH values. The content of Ni increases from 38% to 84% as the mole ratio of NiSO4/FeSO4 increasing from 0.50/0.50 to 0.90/0.10 in electrolyte and slightly decreases from 65% to 42% as the pH values increase from 2.1 to 4.3. The X-ray diffraction analysis reveals that the structures of the films strongly depend on the Ni content in the binary films. The magnetic performance of the films shows that the saturation magnetization (s) decreases from 1775.01 emu/cm3 to 1501.46 emu/cm3 with the pH value increasing from 2.1 to 4.3 and the saturation magnetization (s) and coercivity (c) move up from 1150.44 emu/cm3 and 58.86 Oe to 2498.88 emu/cm3 and 93.12 Oe with the increase of Ni2+ concentration in the electrolyte, respectively.

  6. Structural and tribological properties of CrTiAlN coatings on Mg alloy by closed-field unbalanced magnetron sputtering ion plating

    Science.gov (United States)

    Shi, Yongjing; Long, Siyuan; Yang, Shicai; Pan, Fusheng

    2008-09-01

    In this paper, a series of multi-layer hard coating system of CrTiAlN has been prepared by closed-field unbalanced magnetron sputtering ion plating (CFUBMSIP) technique in a gas mixture of Ar + N 2. The coatings were deposited onto AZ31 Mg alloy substrates. During deposition step, technological temperature and metallic atom concentration of coatings were controlled by adjusting the currents of different metal magnetron targets. The nitrogen level was varied by using the feedback control of plasma optical emission monitor (OEM). The structural, mechanical and tribological properties of coatings were characterized by means of X-ray photoelectron spectrometry, high-resolution transmission electron microscope, field emission scanning electron microscope (FESEM), micro-hardness tester, and scratch and ball-on-disc tester. The experimental results show that the N atomic concentration increases and the oxide on the top of coatings decreases; furthermore the modulation period and the friction coefficient decrease with the N 2 level increasing. The outstanding mechanical property can be acquired at medium N 2 level, and the CrTiAlN coatings on AZ31 Mg alloy substrates outperform the uncoated M42 high speed steel (HSS) and the uncoated 316 stainless steel (SS).

  7. Magnetic Properties of Nanocrystalline Fe{sub x}Cu{sub 1-x} Alloys Prepared by Ball Milling

    Energy Technology Data Exchange (ETDEWEB)

    Yousif, A.; Bouziane, K., E-mail: bouzi@squ.edu.om; Elzain, M. E. [Sultan Qaboos University, Physics Department, College of Science (Oman); Ren, X.; Berry, F. J. [The Open University, Department of Chemistry (United Kingdom); Widatallah, H. M. [Sudan Atomic Energy Commission, Institute of Nuclear Research (Sudan); Al Rawas, A.; Gismelseed, A.; Al-Omari, I. A. [Sultan Qaboos University, Physics Department, College of Science (Oman)

    2004-12-15

    X-ray diffraction, Moessbauer and magnetization measurements were used to study Fe{sub x}Cu{sub 1-x} alloys prepared by ball-milling. The X-ray data show the formation of a nanocrystalline Fe-Cu solid solution. The samples with x{>=}0.8 and x{<=}0.5 exhibit bcc or fcc phase, respectively. Both the bcc and fcc phases are principally ferromagnetic for x{>=}0.2, but the sample with x=0.1 remains paramagnetic down to 78 K. The influence of the local environment on the hyperfine parameters and the local magnetic moment are discussed using calculations based on the discrete-variational method in the local density approximation.

  8. Tensile properties of aluminized V-5Cr-5Ti alloy after exposure in air environment

    Energy Technology Data Exchange (ETDEWEB)

    Natesan, K.; Soppet, W.K. [Argonne National Lab., IL (United States)

    1997-08-01

    The objectives of this task are to (a) develop procedures to modify surface regions of V-Cr-Ti alloys in order to minimize oxygen uptake by the alloys when exposed to environments that contain oxygen, (b) evaluate the oxygen uptake of the surface-modified V-Cr-Ti alloys as a function of temperature an oxygen partial pressure in the exposure environment, (c) characterize the microstructures of oxide scales and oxygen trapped at the grain boundaries of the substrate alloys, and (d) evaluate the influence of oxygen uptake on the tensile properties of the modified alloys at room and elevated temperatures.

  9. Thermal Properties of Al-50%Si Alloys

    Institute of Scientific and Technical Information of China (English)

    Akio Nishimoto; Katsuya Akamatsu; Kazuyoshi Nakao; Kazuo Ichii

    2004-01-01

    In order to prepare a hypereutectic Al-Si alloy with low coefficients of thermal expansion (CTE), Al-50was produced by powder metallurgy (P/M) and ingot metallurgy (I/M). P/M specimen was prepared by mechanical alloying(MA) and pulsed electric-current sintering (PECS). The microstructures of specimens were characterized by optical microscopy and scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDS). Vickers microhardness and CTE measurements were performed. The grains in the P/M specimen were refined with increasing MA time. Primary Si and eutectic Si in the I/M specimen were remarkably refined by adding minute amounts of Sr. The CTE of P/M and I/M specimens were estimated as 7.8×10-6 and 10.7×10-6, respectively. These values were as same as a CTE of Al2O3 ceramics.

  10. Effects of Alloying Elements on Microstructure and Properties of Magnesium Alloys for Tripling Ball

    Science.gov (United States)

    Xiao, D. H.; Geng, Z. W.; Chen, L.; Wu, Z.; Diao, H. Y.; Song, M.; Zhou, P. F.

    2015-10-01

    In order to find good candidate materials for degradable fracturing ball applications, Mg-Al-Zn-Cu alloys with different contents of aluminum, zinc, and copper were prepared by ingot metallurgy. The effects of aluminum, zinc, and copper additions on the microstructure, compressive strength, and rapid decomposition properties of the alloys have been investigated using scanning electron microscopy, compressive tests, and immersion tests. The results show that the addition of high contents Al (15 to 20 wt pct) in pure magnesium promotes a large number of network-like β-Mg17All2 phases, which helps produce more micro-thermocouples to accelerate the corrosion process in 3 wt pct potassium chloride (KCl) at 366 K (93 °C). Adding different Zn contents improves the compressive properties of Mg-20Al alloys drastically. However, it decreases the decomposition rate in 3 wt pct KCl at 366 K (93 °C). Small amount of Cu will slightly reduce the compressive strength of Mg-20Al-5Zn alloy but dramatically increase its decomposition rate.

  11. Microstructure and properties of 2618-Ti heat resistant aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    王建华; 易丹青; 王斌

    2003-01-01

    The mechanical properties of alloy 2618 with 0.5%(mass fraction) titanium and its microstructures in different states such as as-cast and quenching-aging were investigated. Titanium was added into the alloy with Al-5%Ti master alloy that was extruded severely. Al3Ti particles in the microstructure of cast alloy 2618-Ti are very small because those of master alloy are also small. When titanium is used as an alloying element, it does not affect the morphology of Al9FeNi phase in cast alloy, but decreases the grain size of as-cast alloy remarkably. The grain size of quenching-aging alloy 2618 decreases apparently due to the existence of a great deal of dispersive Al3Ti particles. Adding 0.5%Ti has no effect on the room temperature tensile properties of alloy 2618, but apparently increases the elevated temperature instantaneous tensile properties and that of the alloy which is exposed at 250 ℃ for 100 h.

  12. Thermodynamic and surface properties of Sb-Sn and In-Sn liquid alloys

    Indian Academy of Sciences (India)

    B C Anusionwu

    2006-08-01

    The thermodynamic properties of Sb-Sn and In-Sn liquid alloys have been studied using the quasi-chemical model for compound forming binary alloys and that for simple regular alloys. The concentration fluctuation cc(0) and the Warren-Cowley short-range order parameter (1) were determined for the whole concentration range at a temperature of 770 K. The surface tensions of these liquid alloys were determined for the whole concentration range by using energetics determined from thermodynamic calculations. In all calculations, In{Sn manifested properties very close to alloys of ideal mixing, while Sb-Sn showed properties that are asymmetric about equiatomic composition. Our results suggest that a weak complex of the form SbSn2 could be present in the Sb-Sn alloy at a temperature of about 770 K.

  13. Microstructure And Functional Properties Of Prosthetic Cobalt Alloys CoCrW

    Directory of Open Access Journals (Sweden)

    Nadolski M.

    2015-09-01

    Full Text Available The material subject to investigation was two commercial alloys of cobalt CoCrW (No. 27 and 28 used in prosthodontics. The scope of research included performing an analysis of microstructure and functional properties (microhardness, wear resistance and corrosion resistance, as well as dilatometric tests. The examined alloys were characterized by diverse properties, which was considerably influenced by the morphology of precipitates in these materials. Alloy No. 27 has a higher corrosion resistance, whereas alloy No. 28 shows higher microhardness, better wear resistance and higher coefficient of linear expansion. Lower value of the expansion coefficient indicates less probability of initiation of a crack in the facing ceramic material.

  14. Unravelling the materials genome: Symmetry relationships in alloy properties

    Energy Technology Data Exchange (ETDEWEB)

    Toda-Caraballo, Isaac [Department of Materials Science and Metallurgy, University of Cambridge New Museums Site, Pembroke Street, Cambridge, CB2 3QZ (United Kingdom); Galindo-Nava, Enrique I. [Department of Materials Science and Metallurgy, University of Cambridge New Museums Site, Pembroke Street, Cambridge, CB2 3QZ (United Kingdom); Delft University of Technology, Mekelweg 2, Delft 2628 CD (Netherlands); Rivera-Díaz-del-Castillo, Pedro E.J., E-mail: pejr2@cam.ac.uk [Department of Materials Science and Metallurgy, University of Cambridge New Museums Site, Pembroke Street, Cambridge, CB2 3QZ (United Kingdom)

    2013-07-25

    Highlights: ► Research strategy for Accelerated Metallurgy project is outlined. ► Surprising symmetry among atomic, nanoscale and mechanical properties. ► Generalisation of Ashby diagrams via principal component analysis. ► Atomic-related properties can be described with linear regression. ► Mechanical properties modelled via Kocks–Mecking-type physical method. -- Abstract: Metals and alloys have been indispensable for technological progress, but only a fraction of the possible ternary systems (combinations of three elements) is known. Statistical inference methods combined with physical models are presented to discover new systems of enhanced properties. It is demonstrated that properties originating from atomic-level interactions can be described employing a linear regression analysis, but properties incorporating microstructural and thermal history effects require a balance between physical and statistical modelling. In spite of this, there is a remarkable degree of symmetry among all properties, and by employing a principal components analysis it is shown that ten properties essential to engineering can be described well in a three dimensional space. This will aid in the discovery of novel alloying systems.

  15. Unravelling the materials genome: Symmetry relationships in alloy properties

    International Nuclear Information System (INIS)

    Highlights: ► Research strategy for Accelerated Metallurgy project is outlined. ► Surprising symmetry among atomic, nanoscale and mechanical properties. ► Generalisation of Ashby diagrams via principal component analysis. ► Atomic-related properties can be described with linear regression. ► Mechanical properties modelled via Kocks–Mecking-type physical method. -- Abstract: Metals and alloys have been indispensable for technological progress, but only a fraction of the possible ternary systems (combinations of three elements) is known. Statistical inference methods combined with physical models are presented to discover new systems of enhanced properties. It is demonstrated that properties originating from atomic-level interactions can be described employing a linear regression analysis, but properties incorporating microstructural and thermal history effects require a balance between physical and statistical modelling. In spite of this, there is a remarkable degree of symmetry among all properties, and by employing a principal components analysis it is shown that ten properties essential to engineering can be described well in a three dimensional space. This will aid in the discovery of novel alloying systems

  16. Design of experiment (DOE) study of biodegradable magnesium alloy synthesized by mechanical alloying using fractional factorial design

    Science.gov (United States)

    Salleh, Emee Marina; Ramakrishnan, Sivakumar; Hussain, Zuhailawati

    2014-06-01

    The biodegradable nature of magnesium (Mg) makes it a most highlighted and attractive to be used as implant materials. However, rapid corrosion rate of Mg alloys especially in electrolytic aqueous environment limits its performance. In this study, Mg alloy was mechanically milled by incorporating manganese (Mn) as alloying element. An attempt was made to study both effect of mechanical alloying and subsequent consolidation processes on the bulk properties of Mg-Mn alloys. 2k-2 factorial design was employed to determine the significant factors in producing Mg alloy which has properties closes to that of human bones. The design considered six factors (i.e. milling time, milling speed, weight percentage of Mn, compaction pressure, sintering temperature and sintering time). Density and hardness were chosen as the responses for assessing the most significant parameters that affected the bulk properties of Mg-Mn alloys. The experimental variables were evaluated using ANOVA and regression model. The main parameter investigated was compaction pressure.

  17. Effect of alloying on elastic properties of ZrN based transition metal nitride alloys

    KAUST Repository

    Kanoun, Mohammed

    2014-09-01

    We report the effect of composition and metal sublattice substitutional element on the structural, elastic and electronic properties of ternary transition metal nitrides Zr1-xMxN with M=Al, Ti, Hf, V, Nb, W and Mo. The analysis of the elastic constants, bulk modulus, shear modulus, Young\\'s modulus, and Poisson\\'s ratio provides insights regarding the mechanical behavior of Zr1-xMxN. We predict that ternary alloys are more ductile compared to their parent binary compounds. The revealed trend in the mechanical behavior might help for experimentalists on the ability of tuning the mechanical properties during the alloying process by varying the concentration of the transition metal. © 2014 Elsevier B.V.

  18. The influence of chemical composition on the properties and structure Al-Si-Cu(Mg alloys

    Directory of Open Access Journals (Sweden)

    M. Kaczorowski

    2007-04-01

    Full Text Available The mechanical properties of different chemical composition AlSiCuMg type cast alloys after precipitation hardening are presented. The aim of the study was to find out how much the changes in chemistry of aluminum cast alloys permissible by EN-PN standards may influence the mechanical properties of these alloys. Eight AlSi5Cu3(Mg type cast alloys of different content alloying elements were selected for the study. The specimens cut form test castings were subjected to precipitation hardening heat treatment. The age hardened specimens were evaluated using tensile test, hardness measurements and impact test. Moreover, the structure investigation were carried out using either conventional light Metallography and scanning (SEM and transmission (TEM electron microscopy. The two last methods were used for fractography observations and precipitation process observations respectively. It was concluded that the changes in chemical composition which can reach even 2,5wt.% cause essential differences of the structure and mechanical properties of the alloys. As followed from quantitative evaluation and as could be predicted theoretically, copper and silicon mostly influenced the mechanical properties of AlSi5Cu3(Mg type cast alloys. Moreover it was showed that the total concentration of alloying elements accelerated and intensifies the process of decomposition of supersaturated solid solution. The increase of Cu and Mg concentration increased the density of precipitates. It increases of strength properties of the alloys which are accompanied with decreasing in ductility.

  19. Effect of Zn addition on microstructure and mechanical properties of an Al-Mg-Si alloy

    Institute of Scientific and Technical Information of China (English)

    Lizhen Yan; Yongan Zhang; Xiwu Li; Zhihui Li; Feng Wang; Hongwei Liu; Baiqing Xiong

    2014-01-01

    In the present work, an Al-0.66Mg-0.85Si-0.2Cu alloy with Zn addition was investigated by electron back scattering diffraction (EBSD), high resolution electron microscopy (HREM), tensile and Erichsen tests. The mechanical properties of the alloy after pre-aging met the standards of sheet forming. After paint baking, the yield strength of the alloy was improved apparently. GP(II) zones andηʹphases were formed during aging process due to Zn addition. With the precipitation of GP zones,β″phases, GP(II) zones andηʹphases, the alloys displayed excellent mechanical properties.

  20. Effect of hot extrusion process on microstructure and mechanical properties of hypereutectic Al-Si alloys

    OpenAIRE

    Li Runxia; Yu Fuxiao; Zuo Liang

    2011-01-01

    The hypereutectic Al-Si alloy was fabricated by hot extrusion process after solidified under electromagnetic stirring, and the microstructure and mechanical properties of the alloy were studied. The results show that the ultimate tensile strength and elongation of the alloy reached 229.5 MPa and 4.6%, respectively with the extrusion ratio of 10, and 263.2 MPa and 5.4%, respectively with extrusion ratio of 20. This indicates that the mechanical properties of the alloy are obviously improved w...

  1. Effect of Zn addition on microstructure and mechanical properties of an Al–Mg–Si alloy

    Directory of Open Access Journals (Sweden)

    Lizhen Yan

    2014-04-01

    Full Text Available In the present work, an Al–0.66Mg–0.85Si–0.2Cu alloy with Zn addition was investigated by electron back scattering diffraction (EBSD, high resolution electron microscopy (HREM, tensile and Erichsen tests. The mechanical properties of the alloy after pre-aging met the standards of sheet forming. After paint baking, the yield strength of the alloy was improved apparently. GP(II zones and ηʹ phases were formed during aging process due to Zn addition. With the precipitation of GP zones, β″ phases, GP(II zones and ηʹ phases, the alloys displayed excellent mechanical properties.

  2. Ideal solution behaviour of glassy Cu–Ti, Zr, Hf alloys and properties of amorphous copper

    Energy Technology Data Exchange (ETDEWEB)

    Ristić, R. [Department of Physics, University of Osijek, Trg Ljudevita Gaja 6, HR-3100 Osijek (Croatia); Cooper, J.R. [Department of Physics, Cavendish Laboratory, J.J. Thomson Avenue, CB3 0HE Cambridge (United Kingdom); Zadro, K.; Pajić, D. [Department of Physics, Faculty of Science, Bijenička cesta 32, HR-10002 Zagreb (Croatia); Ivkov, J. [Institute of Physics, Bijenička cesta 46, HR-10002 Zagreb (Croatia); Babić, E. [Department of Physics, Faculty of Science, Bijenička cesta 32, HR-10002 Zagreb (Croatia)

    2015-02-05

    Highlights: • Ideal solution behaviour (ISB) is established in all Cu–Ti, Zr, Hf glassy alloys. • ISB enables reliable estimates for various properties of amorphous Cu. • ISB also impacts glass forming ability in these and probably other similar alloys. - Abstract: A comprehensive study of selected properties of amorphous (a) Cu–TE alloys (TE = Ti, Zr and Hf) has been performed. Data for average atomic volumes of a-Cu–Hf, Ti alloys combined with literature data show that ideal solution behaviour (Vegard’s law) extends over the whole glass forming range (GFR) in all a-Cu–TE alloys. This enables one to obtain an insight into some properties and probable atomic arrangements for both, a-TEs (Ristić et al., 2010) and a-Cu by extrapolation of the data for alloys. Indeed the atomic volumes and other properties studied for all a-Cu–TE alloys extrapolate to the same values for a-Cu. Depending on the property, these values are either close to those of crystalline (c) Cu, or are close to those for liquid (L) Cu. In particular, the electronic transport properties of a-Cu seem close to those of L-Cu, whereas the static properties, such as the density of states, and Young’s modulus, converge to those of c-Cu. The possible impact of these results on our understanding of a-Cu–TE alloys, including glass forming ability, is discussed.

  3. Microstructure and corrosion properties of the laser treated SUPERSTON alloy

    OpenAIRE

    W. Serbiński; B. Majkowska

    2006-01-01

    Purpose: Results of laser treatment at cryogenic conditions and its influence on microstructure, microhardnessand properties of the SUPERSTON alloy are presented in this article.Design/methodology/approach: New method of the laser remelting specimens diped in liquid nitrogen madeby the CO2 laser with 6000W laser beam power and scanning velocity 1.0 m/min was employed. Observationmicrostructure was carried out by scanning electron microscope. Hardness of cross-section of the surface layerhas b...

  4. Influence of hot extrusion on microstructure and mechanical properties of AZ31 magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    WANG Ling; TIAN Su-gui; MENG Fan-lai; DU Hong-qiang

    2006-01-01

    Extrusion treatment is a common method to refine the grain size and improve the mechanical properties of metal material. The influence of hot extrusion on microstructure and mechanical properties of AZ31 magnesium alloy was investigated. The results show that the mechanical properties of AZ31 alloy are obviously improved by extrusion treatment. The ultimate tensile strength (UTS) of AZ31 alloy at room temperature is measured to be 222 MPa, and is enhanced to 265.8 MPa after extrusion at 420℃. The yield tensile strength (YTS) of AZ31 alloy at room temperature is measured to be 84 MPa, and is enhanced to 201 MPa after extrusion at 420℃. The effective improvements on mechanical properties result from the formation of the finer grains during extrusion and the finer particles precipitated by age treatment. The features of the microstructure evolution during hot extruded of AZ31 alloy are dislocation slipping on the matrix and occurrence of the dynamic recrystallization.

  5. Alloys and composites of polybenzoxazines properties and applications

    CERN Document Server

    Rimdusit, Sarawut; Tiptipakorn, Sunan

    2013-01-01

    This book provides an introduction to the unique and fascinating properties of alloys and composites from novel commercialized thermosetting resins based on polybenzoxazines. Their outstanding properties such as processability, thermal, mechanical, electrical properties as well as ballistic impact properties of polybenzoxazine alloys and composites make them attractive for various applications in electronic packaging encapsulation, light weight ballistic armour composites and bipolar plate in fuel cells.

  6. Effect of Pressure on Microstructure and Mechanical Properties of AM60B Alloy Used for Motorcycle Wheels Formed by Double Control Forming

    Institute of Scientific and Technical Information of China (English)

    Jufu Jiang; Yuansheng Cheng; Zhiming Du; Jun Liu; Yuanfa Li; Shoujing Luo

    2013-01-01

    A set of novel forming die combining the advantages of dies casting and forging was designed,by which double control forming idea was firstly proposed.The motorcycle wheel made of AM60B alloy was used as the typical component to demonstrate advantages of the double control forming.The effect of pressure on the mechanical properties and microstructure of the parts formed by double control forming was investigated.The results showed that high mechanical properties and complex shape were achieved in the parts formed by double control forming.Compared to die casting,the mechanical properties of the formed part significantly increased and the microstructure changed from the coarse dendrites to fine aquiaxed grains.The shrinkage voids and microcracks in the formed parts were obviously reduced or even completely eliminated with the increase of pressure.When a pressure of 4000 kN was applied,the optimal mechanical properties such as ultimate tensile strength of 265.6 MPa and elongation of 21% were achieved and the microstructure was characterized by fine and uniform equiaxed grains due to the large undercooling degree caused by the high pressure.

  7. Improving tensile properties of dilute Mg-0.27Al-0.13Ca-0.21Mn (at.%) alloy by low temperature high speed extrusion

    International Nuclear Information System (INIS)

    As-cast Mg-0.27Al-0.13Ca-0.21Mn (at.%) alloy was extruded at temperatures from 350 °C to 500 °C. We examined the microstructural changes during extrusion at different temperatures to clarify dynamic recrystallization mechanisms during extrusion, and also investigated the effect of extrusion temperature on microstructures and mechanical properties of the alloy. High extrusion exit speed of 60 m/min was successfully achieved at wide range of temperatures from 350 °C to 500 °C even when as-cast dilute Mg-0.27Al-0.13Ca-0.21Mn (at.%) alloy was used as a billet for the extrusion. The extrusion at low temperature refines grain size and weakens basal texture due to continuous dynamic recrystallization (CDRX) together with double twinning. As a result, the alloy sample extruded at 350 °C exhibits higher tensile proof stress of 206 MPa and higher tensile ductility of 29% than T5-treated 6063 aluminum alloy and commercial AZ31 magnesium alloy even in an as-extruded condition. Furthermore, Hall–Petch coefficient for compressive proof stress is 1.8 times larger than that for tensile one, resulting in improvement of yield stress anisotropy (compressive proof stress/tensile yield stress ratio). - Highlights: • Dilute Mg–Al–Ca–Mn alloy can be extruded at high die-exit speed of 60 m/min. • The extrusion at low temperature refines recrystallized grain size and weakens basal texture. • Grain refining improves mechanical properties of dilute Mg–Al–Ca–Mn alloys

  8. Improving tensile properties of dilute Mg-0.27Al-0.13Ca-0.21Mn (at.%) alloy by low temperature high speed extrusion

    Energy Technology Data Exchange (ETDEWEB)

    Nakata, T., E-mail: s123055@stn.nagaokaut.ac.jp [Nagaoka University of Technology, 1603-1, Kamitomioka, Nagaoka 940-2188 (Japan); Mezaki, T.; Xu, C.; Oh-ishi, K. [Nagaoka University of Technology, 1603-1, Kamitomioka, Nagaoka 940-2188 (Japan); Shimizu, K.; Hanaki, S. [Sankyo Tateyama, Inc., Sankyo Material-Company, 8-3, Nagonoe, Imizu, Toyama 934-8515 (Japan); Kamado, S. [Nagaoka University of Technology, 1603-1, Kamitomioka, Nagaoka 940-2188 (Japan)

    2015-11-05

    As-cast Mg-0.27Al-0.13Ca-0.21Mn (at.%) alloy was extruded at temperatures from 350 °C to 500 °C. We examined the microstructural changes during extrusion at different temperatures to clarify dynamic recrystallization mechanisms during extrusion, and also investigated the effect of extrusion temperature on microstructures and mechanical properties of the alloy. High extrusion exit speed of 60 m/min was successfully achieved at wide range of temperatures from 350 °C to 500 °C even when as-cast dilute Mg-0.27Al-0.13Ca-0.21Mn (at.%) alloy was used as a billet for the extrusion. The extrusion at low temperature refines grain size and weakens basal texture due to continuous dynamic recrystallization (CDRX) together with double twinning. As a result, the alloy sample extruded at 350 °C exhibits higher tensile proof stress of 206 MPa and higher tensile ductility of 29% than T5-treated 6063 aluminum alloy and commercial AZ31 magnesium alloy even in an as-extruded condition. Furthermore, Hall–Petch coefficient for compressive proof stress is 1.8 times larger than that for tensile one, resulting in improvement of yield stress anisotropy (compressive proof stress/tensile yield stress ratio). - Highlights: • Dilute Mg–Al–Ca–Mn alloy can be extruded at high die-exit speed of 60 m/min. • The extrusion at low temperature refines recrystallized grain size and weakens basal texture. • Grain refining improves mechanical properties of dilute Mg–Al–Ca–Mn alloys.

  9. Surface modification by alkali and heat treatments in titanium alloys.

    Science.gov (United States)

    Lee, Baek-Hee; Do Kim, Young; Shin, Ji Hoon; Hwan Lee, Kyu

    2002-09-01

    Pure titanium and titanium alloys are normally used for orthopedic and dental prostheses. Nevertheless, their chemical, biological, and mechanical properties still can be improved by the development of new preparation technologies. This has been the limiting factor for these metals to show low affinity to living bone. The purpose of this study is to improve the bone-bonding ability between titanium alloys and living bone through a chemically activated process and a thermally activated one. Two kinds of titanium alloys, a newly designed Ti-In-Nb-Ta alloy and a commercially available Ti-6Al-4V ELI alloy, were used in this study. In this study, surface modification of the titanium alloys by alkali and heat treatments (AHT), alkali treated in 5.0M NaOH solution, and heat treated in vacuum furnace at 600 degrees C, is reported. After AHT, the effects of the AHT on the bone integration property were evaluated in vitro. Surface morphologies of AHT were observed by optical microscopy (OM) and scanning electron microscopy (SEM). Chemical compositional surface changes were investigated by X-ray diffractometry (XRD), energy dispersive spectroscopy (EDS), and auger electron spectroscopy (AES). Titanium alloys with surface modification by AHT showed improved bioactive behavior, and the Ti-In-Nb-Ta alloy had better bioactivity than the Ti-6Al-4V ELI alloy in vitro.

  10. Microstructural and thermophysical properties of U-6 wt.%Zr alloy for fast reactor application

    Science.gov (United States)

    Kaity, Santu; Banerjee, Joydipta; Nair, M. R.; Ravi, K.; Dash, Smruti; Kutty, T. R. G.; Kumar, Arun; Singh, R. P.

    2012-08-01

    The microstructural and high temperature behavior of U-6 wt.%Zr alloy has been investigated in this study. U-6 wt.%Zr alloy sample for this study was prepared by following injection casting route. The thermophysical properties like coefficient of thermal expansion, specific heat, thermal conductivity of the above alloy were determined. The hot-hardness data of the U-6 wt.%Zr alloy was also generated from room temperature to 973 K. Apart from that, the fuel-clad chemical compatibility with T91 grade steel was also studied by diffusion couple experiment. No studies have been reported on U-6 wt.%Zr alloy. This paper aims at filling up the gap on characterization and thermophysical property evaluation of U-6 wt.%Zr alloy.

  11. Study on comprehensive properties of duplex austenitic surfacing alloys for impacting abrasion

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In this paper, comprehensive property crack resistance, work hardening and abrasion resistance of a series of double-phases austenitic alloys(FAW) has been studied by means of SEM, TEM and type MD-10 impacting wear test machine. FAW alloys are of middle chromium and low manganese, including Fe-Cr-Mo-C alloy,Fe-Cr-Mn-C alloy and Fe-Cr-Mn-Ni-C alloy, that are designed for working in condition of impacting abrasion resistance hardfacing.Study results show that the work hardening mechanism of FAW alloys are mainly deformation high dislocation density and dynamic carbide aging, the form of wearing is plastic chisel cutting. Adjusting the amount of carbon, nickel, manganese and other elements in austenitic phase area, the FAW alloy could fit different engineering conditions of high impacting, high temperature and so on.

  12. Hydrogen Desorption Properties of Nanocrystalline MgH2-10 wt.% ZrB2 Composite Prepared by Mechanical Alloying

    Directory of Open Access Journals (Sweden)

    Mona Maddah

    2014-06-01

    Full Text Available Storage of hydrogen is one of the key challenges in developing hydrogen economy. Magnesium hydride (MgH2 is an attractive candidate for solid-state hydrogen storage for on-board applications. In this study, 10 wt.% ZrB2 was co-milled with magnesium hydride at different milling times to produce nanocrystalline composite powder. The effect of milling time and additive on the hydrogen desorption properties of obtained powder was evaluated by thermal analyzer method and compared with pure MgH2. The phase constituents of powder particles were characterized by X-ray diffractometry method. The grain size and lattice strain of β-MgH2 phase were estimated from the broadening of XRD peaks using Williamson–Hall method. The size and morphological changes of powder particles upon mechanical alloying were studied by scanning electron microscopy. XRD analysis showed that the mechanically activated magnesium hydride consisted of β-MgH2, γ-MgH2 and small amount of MgO. It is shown that the addition of ZrB2 to magnesium hydride yields a finer particle size. The thermal analyses results showed that the addition of ZrB2 particle to magnesium hydride and mechanical alloying for 30 h reduced the dehydrogenation temperature of magnesium hydride from 319 °C to 308 °C. This can be attributed to the particle size reduction of magnesium hydride.

  13. Corrosion Behavior of AlSi10Mg Alloy Produced by Additive Manufacturing (AM vs. Its Counterpart Gravity Cast Alloy

    Directory of Open Access Journals (Sweden)

    Avi Leon

    2016-06-01

    Full Text Available The attractiveness of additive manufacturing (AM relates to the ability of this technology to rapidly produce very complex components at affordable costs. However, the properties and corrosion behavior, in particular, of products produced by AM technology should at least match the properties obtained by conventional technologies. The present study aims at evaluating the corrosion behavior and corrosion fatigue endurance of AlSi10Mg alloy produced by selective laser melting (SLM in comparison with its conventional counterpart, gravity cast alloy. The results obtained indicate that the corrosion resistance of the printed and cast alloys was relatively similar, with a minor advantage to the printed alloy. The corrosion fatigue endurance of the printed alloy was relatively improved compared to the cast alloy. This was mainly attributed to the significant differences between the microstructure and defect characteristics of those two alloys.

  14. Effect of heterogeneous precipitation caused by segregation of substitutional and interstitial elements on mechanical properties of a β-type Ti alloy

    International Nuclear Information System (INIS)

    This study investigates the effect of heterogeneous precipitation induced by the segregation of substitutional and interstitial elements in Ti–29Nb–13Ta–4.6Zr alloy (TNTZ) on its mechanical properties. For this, samples both with and without segregation of substitutional elements were prepared, with only the latter being subjected to long-term homogenization. It was found that micro-scale segregation of substitutional elements such as Nb, Ta, and Zr does not significantly affect mechanical properties such as fatigue strength, not even if heterogeneous precipitation occurs as a result of this segregation. On the other hand, segregation of interstitial elements was achieved by controlling the aging time. The segregation of interstitial elements creates precipitate-free zones (PFZs), grain boundary (GB) plates, and Widmanstätten α phases with migrating O atoms that all significantly affect the mechanical properties. Specifically, the PFZs have the potential to improve fatigue life, while the Widmanstätten α phase increases the tensile strength and reduces the fatigue ratio, the GB-plates reduce elongation, These results indicate that the formation of a Widmanstätten α phase by the migration of interstitial elements has a varying influence on the tensile and fatigue properties

  15. La2O3 effects on TZM alloy recovery, recrystallization and mechanical properties

    International Nuclear Information System (INIS)

    Titanium, zirconium and molybdenum (TZM) alloy with different amounts of rare earth lanthanum oxide was prepared by powder metallurgy into 0.5 mm thick sheets. The effects of the La2O3 content on recrystallization temperature and mechanical properties of the TZM alloy were studied. La2O3 increased the recrystallization and recovery temperature of the TZM alloy and increased its tensile strength and elongation

  16. Microstructure and properties of laser surface alloyed PM austenitic stainless steel

    OpenAIRE

    Z. Brytan; M. Bonek; L.A. Dobrzański

    2010-01-01

    Purpose: The purpose of this paper is to analyse the effect of laser surface alloying with chromium on the microstructural changes and properties of vacuum sintered austenitic stainless steel type AISI 316L (EN 1.4404).Design/methodology/approach: Surface modification of AISI 316L sintered austenitic stainless steel was carried out by laser surface alloying with chromium powder using high power diode laser (HPDL). The influence of laser alloying conditions, both laser beam power (between 0.7 ...

  17. Effects of Al-Mn-Ti-P-Cu master alloy on microstructure and properties of Al-25Si alloy

    Directory of Open Access Journals (Sweden)

    Xu Chunxiang

    2013-09-01

    Full Text Available To obtain a higher microstructural refining efficiency, and improve the properties and processing ability of hypereutectic Al-25Si alloy, a new environmentally friendly Al-20.6Mn-12Ti-0.9P-6.1Cu (by wt.% master alloy was fabricated; and its modification and strengthening mechanisms on the Al-25Si alloy were studied. The mechanical properties of the unmodified, modified and heat treated alloys were investigated. Results show that the optimal addition amount of the Al-20.6Mn-12Ti-0.9P-6.1Cu master alloy is 4wt.%. In this case, primary Si and eutectic Si as well as メ-Al phase were clearly refined, and this refining effect shows an excellent long residual action as it can be heat-retained for at least 5 h. After being T6 heat treated, the morphology of primary and eutectic Si in the Al-25Si alloys with the addition of 4wt.% Al-20.6Mn-12Ti-0.9P-6.1Cu alloy changes into particles and short rods. The average grain size of the primary and eutectic Si decreases from 250 レm (unmodified to 13.83 レm and 35 レm (unmodified to 7 レm; the メ-Al becomes obviously finer and the distribution of Si phases tends to be uniform and dispersed. Meanwhile, the tensile properties are improved obviously; the tensile strengths at room temperature and 300 ìC reach 241 MPa and 127 MPa, increased by 153.7% and 67.1%, respectively. In addition, the tensile fracture mechanism changes from brittle fracture for the alloy without modification to ductile fracture after modification. Modifying the morphology of Si phase and strengthening the matrix can effectively block the initiation and propagation of cracks, thus improving the strength of the hypereutectic Al-25Si alloy.

  18. Influence of niobium addition on the high temperature mechanical properties of a centrifugally cast HP alloy

    International Nuclear Information System (INIS)

    The influence of niobium addition on the mechanical properties at high temperature of HP alloy has been investigated. Two HP alloys were centrifugally cast with a similar chemical composition differing only in the niobium content. Low strain rate high temperature tensile tests and creep-rupture tests were performed in the range of 900–1100 °C, and the results compared between the alloys. According to the results, the high temperature mechanical behavior of both alloys is controlled by several factors like solid solution, network of eutectic carbides, intradendritic precipitation and dendrite spacing. A significant increase in the mechanical properties for the HP alloy with niobium addition was found within the temperature range of 900–1050 °C. Beyond this temperature the mechanical behavior of both alloys is basically the same

  19. Effects of chemical coating with Ni on electrochemical properties of Mg2Ni hydrogen storage alloys

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The effects of nickel coating on the electrochemical properties of Mg2Ni hydrogen storage alloys are presented in this paper. X-ray diffraction (XRD) and scanning electron microscope (SEM) techniques were employed to examine the crystal structure and surface morphologies of the bare and Ni-coated Mg2Ni alloys. The electrochemical properties of alloys were characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The results showed that Ni coating not only decreased the charge transfer resistance, but also decreased the H atom diflusion resistance for Mg2Ni alloys. It was also found that Ni coating effectively improved the discharge capacity, but decreased the cycling performance of the as-synthesized Ni-coated Mg2Ni alloys. The discharge current has a great impact on the cycling performance of the as-synthesized Ni-coated Mg2Ni alloys.

  20. Influence of niobium addition on the high temperature mechanical properties of a centrifugally cast HP alloy

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, A.R., E-mail: arandrade@gmail.com [Department of Materials Engineering, Federal University of São Carlos, Rod. Washington Luiz, km 235, São Carlos, SP (Brazil); Department of Research and Development, ENGEMASA – Engineering and Materials Ltda., Rua Ernesto Cadinalli, 303, São Carlos, SP (Brazil); Bolfarini, C. [Department of Materials Engineering, Federal University of São Carlos, Rod. Washington Luiz, km 235, São Carlos, SP (Brazil); Ferreira, L.A.M.; Vilar, A.A.A. [Department of Research and Development, ENGEMASA – Engineering and Materials Ltda., Rua Ernesto Cadinalli, 303, São Carlos, SP (Brazil); Souza Filho, C.D.; Bonazzi, L.H.C. [Department of Research and Development, ENGEMASA – Engineering and Materials Ltda., Rua Ernesto Cadinalli, 303, São Carlos, SP (Brazil); Department of Materials, Aeronautical and Automotive Engineering, University of São Paulo, Av. Trabalhador Sancarlense, 400, São Carlos, SP (Brazil)

    2015-03-25

    The influence of niobium addition on the mechanical properties at high temperature of HP alloy has been investigated. Two HP alloys were centrifugally cast with a similar chemical composition differing only in the niobium content. Low strain rate high temperature tensile tests and creep-rupture tests were performed in the range of 900–1100 °C, and the results compared between the alloys. According to the results, the high temperature mechanical behavior of both alloys is controlled by several factors like solid solution, network of eutectic carbides, intradendritic precipitation and dendrite spacing. A significant increase in the mechanical properties for the HP alloy with niobium addition was found within the temperature range of 900–1050 °C. Beyond this temperature the mechanical behavior of both alloys is basically the same.

  1. Comparison of Impact Properties for Carbon and Low Alloy Steels

    Institute of Scientific and Technical Information of China (English)

    O.H. Ibrahim

    2011-01-01

    The impact properties of hot rolled carbon steel (used for the manufacture of reinforcement steel bars) and the quenched & tempered (Q&T) low alloy steel (used in the pressure vessel industry) were determined. The microstructure of the hot rolled carbon steel contained ferrite/pearlite phases, while that of the quenched and tempered low alloy steel contained bainite structure. Impact properties were determined for both steels by instrumented impact testing at temperatures between -150 and 200℃. The impact properties comprised total impact energy, ductile to brittle transition temperature, crack initiation and propagation energy, brittleness transition temperature and cleavage fracture stress. The Q&T low alloy steel displayed much higher resistance to ductile fracture at high test temperatures, while its resistance to brittle fracture at low test temperatures was a little higher than that of the hot rolled carbon steel. The results were discussed in relation to the difference in the chemical composition and microstructure for the two steels.

  2. Properties of titanium-alloyed DLC layers for medical applications.

    Science.gov (United States)

    Joska, Ludek; Fojt, Jaroslav; Cvrcek, Ladislav; Brezina, Vitezslav

    2014-01-01

    DLC-type layers offer a good potential for application in medicine, due to their excellent tribological properties, chemical resistance, and bio-inert character. The presented study has verified the possibility of alloying DLC layers with titanium, with coatings containing three levels of titanium concentration prepared. Titanium was present on the surface mainly in the form of oxides. Its increasing concentration led to increased presence of titanium carbide as well. The behavior of the studied systems was stable during exposure in a physiological saline solution. Electrochemical impedance spectra practically did not change with time. Alloying, however, changed the electrochemical behavior of coated systems in a significant way: from inert surface mediating only exchange reactions of the environment in the case of unalloyed DLC layers to a response corresponding rather to a passive surface in the case of alloyed specimens. The effect of DLC layers alloying with titanium was tested by the interaction with a simulated body fluid, during which precipitation of a compound containing calcium and phosphorus--basic components of the bone apatite--occurred on all doped specimens, in contrast to pure DLC. The results of the specimens' surface colonization with cells test proved the positive effect of titanium in the case of specimens with a medium and highest content of this element.

  3. Structural defects in Fe–Pd-based ferromagnetic shape memory alloys: tuning transformation properties by ion irradiation and severe plastic deformation

    International Nuclear Information System (INIS)

    Fe–Pd-based ferromagnetic shape memory alloys constitute an exciting class of magnetically switchable smart materials that reveal excellent mechanical properties and biocompatibility. However, their application is severely hampered by a lack of understanding of the physics at the atomic scale. A many-body potential is presented that matched ab inito calculations and can account for the energetics of martensite ↔ austenite transition along the Bain path and relative phase stabilities in the ordered and disordered phases of Fe–Pd. Employed in massively parallel classical molecular dynamics simulations, the impact of order/disorder, point defects and severe plastic deformation in the presence of single- and polycrystalline microstructures are explored as a function of temperature. The model predictions are in agreement with experiments on phase changes induced by ion irradiation, cold rolling and hammering, which are also presented. (paper)

  4. Effect of Mo content on thermal and mechanical properties of Mo–Ru–Rh–Pd alloys

    International Nuclear Information System (INIS)

    Metallic inclusions are precipitated in irradiated oxide fuels. The composition of the phases varies with the burnup and the conditions such as temperature gradients and oxygen potential of the fuel. In the present work, Mox/(0.7+x) (Ru0.5Rh0.1Pd0.1)(0.7)/(0.7+x) (x = 0, 0.05, 0.1, 0.15, 0.2, and 0.25) alloys were prepared by arc melting, followed by annealing in a high vacuum. The thermal and mechanical properties of the alloys such as elastic moduli, Debye temperature, micro-Vickers hardness, electrical resistivity, and thermal conductivity have been evaluated to elucidate the effect of Mo content on these physical properties of the alloys. The alloys with lower Mo contents show higher thermal conductivity. The thermal conductivity of the alloy with x = 0 is almost twice of that of the alloy with x = 0.25. The thermal conductivities of the alloys are dominated by electronic contribution, which has been evaluated using the Wiedemann–Franz–Lorenz relation from the electrical resistivity data. It is confirmed that the variation of the Mo contents of the alloys considerably affects the mechanical and thermal properties of the alloys

  5. Microstructures and mechanical properties of AZ31-0.1Ca magnesium alloy produced by soft-contact electromagnetic casting and hot extrusion

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    An AZ31-0.1Ca magnesium alloy produced by Soft-contact electromagnetic continuous casting(SEMC) was investigated.The fine homogeneous structure and the precipitated phases were obtained by SEMC.The effects of microalloying of Ca and middle frequency electromagnetic field on AZ31-0.1Ca magnesium alloy were discussed.And the as-cast billets were extruded with different extrusion ratios subsequently.The alloy showed an ultrafine grain size of 2-5 μm due to dynamic recrytallization(DRX) in the course of hot ext...

  6. Microstructure and properties of laser-borided Inconel 600-alloy

    Energy Technology Data Exchange (ETDEWEB)

    Kulka, M., E-mail: michal.kulka@put.poznan.pl; Dziarski, P.; Makuch, N.; Piasecki, A.; Miklaszewski, A.

    2013-11-01

    Nickel-based superalloys are used extensively for a variety of industrial applications involving high temperatures and aggressive environments. However, under conditions of appreciable mechanical wear (adhesive or abrasive), these materials have to be distinguished by suitable wear protection. The diffusion boronizing is the thermo-chemical treatment, which improves the tribological properties of nickel and its alloys. Nevertheless, the long duration of this process is necessary in order to obtain the layers of the thickness up to about 100 μm. Instead of the diffusion process, in this study the laser boriding is used for producing boride layer on Inconel 600-alloy. During the laser alloying, the external cylindrical surface of base material is coated by paste, including amorphous boron. Then the surface is re-melted by a laser beam. The high overlapping of multiple laser tracks (86%) causes the formation of uniform laser-alloyed layer in respect of the thickness. Laser re-melted zone, heat-affected zone and the substrate characterize the microstructure. In the re-melted zone, the three areas are observed: compact borides zone consisting of nickel, chromium and iron borides (close to the surface), zone of increased percentage of Ni–Cr–Fe-matrix (appearing in the greater distance from the surface) and zone of dominant Ni–Cr–Fe-matrix percentage (at the end of the layer). The hardness obtained is comparable to that-obtained in case of diffusion boriding. Simultaneously, the laser-borided layers are significantly thicker (about 346 or 467 μm depending on the laser power used). The significant increase in their abrasive wear resistance is observed. The wear intensity factors, as well as the relative mass loss of the laser-borided samples, are ten times smaller in comparison with untreated Inconel 600-alloy.

  7. Dynamic nanomechanical properties of novel Si-rich intermetallic coatings growth on a medical 316 LVM steel by hot dipping in a hypereutectic Al-25Si alloy.

    Science.gov (United States)

    Frutos, E; González-Carrasco, J L

    2015-06-01

    This aim of this study is to determine the elastoplastic properties of Ni-free Al3FeSi2 intermetallic coatings grown on medical stainless steel under different experimental conditions. Elastoplastic properties are defined by the plasticity index (PI), which correlates the hardness and the Young's modulus. Special emphasis is devoted to correlate the PI with the wear resistance under sliding contact, determined by scratch testing, and fracture toughness, determined by using a novel method based on successive impacts with small loads. With regard to the substrate, the developed coatings are harder and exhibit a lower Young's reduced modulus, irrespective of the experimental conditions. It has been shown that preheating of the samples prior to hot dipping and immersion influences the type and volume fraction of precipitates, which in turn also affect the nanomechanical properties. The higher the preheating temperature is, the greater the Young's reduced modulus is. For a given preheating condition, an increase of the immersion time yields a decrease in hardness. Although apparent friction coefficients of coated specimens are smaller than those obtained on AISI 316 LVM, they increase when using preheating or higher immersion times during processing, which correlates with the PI. The presence of precipitates produces an increase in fracture toughness, with values greater than those presented by samples processed on melted AlSi alloys with lower Si content (12 wt%). Therefore, these intermetallic coatings could be considered "hard but tough", suitable to enhance the wear resistance, especially when using short periods of immersion. PMID:25778350

  8. Mechanical properties and microstructures of a wrought AZ91 alloy

    Institute of Scientific and Technical Information of China (English)

    YAN Yunqi; ZHANG Tingjie; ZHOU Lian; DENG Ju

    2004-01-01

    Effects of hot plastic deformation on microstructures and tensile properties of AZ91 alloy were investigated. Compared with as-T4 microstructures, the as-extruded samples of AZ91 alloy with fine grains exhibit better strength and ductility due to dynamic recrystallization. The succeeded rotation forging also provides finer grains while the strength in creases, but the elongation decreases. Simultaneously, wrought AZ91 alloy shows more balance properties than as-T4 condition ones. An interesting elongation of 228.5% is attained in the as-extruded AZ91 alloy in spite of the coarse grains with the size of 85 μm. The two-step method enhances the superplastic property of AZ91 alloy. The microstructure is still keep ing the same scale of grains after superplastic testing.

  9. Effect of Zn on mechanical property and corrosion property of extruded Mg-Zn-Mn alloy

    Institute of Scientific and Technical Information of China (English)

    YIN Dong-song; ZHANG Er-lin; ZENG Song-yan

    2008-01-01

    The effect of Zn on the microstructure, the mechanical property and the corrosion property in simulated body fluid(SBF) of an extruded Mg-Mn alloy was studied. The results indicate that the addition of Zn element can significantly refine the grain size of the extruded Mg-Mn alloy. When Zn content is increased from 0% to 3%, the grain size decreases from 12 μm to 4 μm. Meanwhile, the mechanical properties also increase remarkably with increasing Zn content. When Zn content is 3%, the ultimate tensile strength and the yield strength are increased by 54.7 MPa and 69.7 MPa, respectively. Zn can also improve the anti-corrosion property of the alloy. The best anti-corrosion property is obtained with 1% Zn. However, further increase of Zn content up to 3% deteriorates the corrosion property. Finally, the influence mechanism of Zn on the microstructure, the mechanical property and the corrosion property was discussed.

  10. Interfacial properties of immiscible Co-Cu alloys

    DEFF Research Database (Denmark)

    Egry, I.; Ratke, L.; Kolbe, M.;

    2010-01-01

    Using electromagnetic levitation under microgravity conditions, the interfacial properties of an Cu75Co25 alloy have been investigated in the liquid phase. This alloy exhibits a metastable liquid miscibility gap and can be prepared and levitated in a configuration consisting of a liquid cobalt-ri...... experiment carried out on board the TEXUS 44 sounding rocket....

  11. Structure and tribological properties of modified layer on 2024 aluminum alloy by plasma-based ion implantation with nitrogen/titanium/carbon

    Institute of Scientific and Technical Information of China (English)

    张玲召; 廖家轩; 夏立芳; 刘维民; 徐洮; 薛群基

    2003-01-01

    2024 aluminum alloy was implanted with nitrogen then titanium finally carbon by plasma-based ion implantatio to form a gradient layer.The structure and tribological properties of the layer were investigated.Its composition profiles and chemical states were analyzed with X-ray photoelectron spectroscopy(XPS).The surface carbonlayer was analyzed by Raman spectrum.The appearances were observed by atomic force microscope(AFM).Thesurface hardness was measured with the mechanical property microprobe.The dry wear tests against GCr15 steelball at various sliding loads were performed with a ball-on-disk wear tester in ambient environment.The resultsshow that the thickness of the modified layer is 1 200 nm,the carbon layer is a smooth and compact diamond-likecarbon(DLC)films,and the carbon-titanium interface is broadened due to carbon ions implantation,resulting in agood composition and structure transition between DLC films and titanium layer.Surface hardness is improvedmarkedly,with a slow and uniform change.Tribological properties are improved greatly although they reduce withthe increase of sliding loads because the modified layer becomes thin rapidly.

  12. Effects of minor amounts of scandium on microstructure and mechanical properties of ZA27 alloy

    Directory of Open Access Journals (Sweden)

    Xiang Qingchun

    2013-09-01

    Full Text Available The influences of minor amounts of scandium on the microstructure and mechanical properties of as-cast ZA27 alloy have been experimentally investigated. The experimental results show that as far as the Sc addition is individually concerned, the refinement result of the as-cast ZA27 alloy with 0.5wt.%Sc addition is comparatively better. After alloying with minor amounts of Sc, the coarse dendrites of the ZA27 alloy are refined and transformed into the uniform and small equiaxed grain microstructure; also the eutectics among the grain boundaries become finer. The test results of mechanical properties show that the tensile strength and hardness of the as-cast ZA27 alloy containing 0.5wt.%Sc approach 495 MPa and 120.2 HB, increase by 28.5% and 33.1%, respectively, compared with those of the ZA27 alloy with no addition of Sc element, while the elongation of the alloy is improved to 7.6% from 2.7%. The SEM, EDAX and XRD analyses show that in the ZA27 alloy, the trace element Sc combines with Al to form the square Al3Sc phase particles, which serve as heterogeneous nuclei, facilitating the refinement of the microstructure and the improvement of the mechanical properties of the alloy.

  13. Cu-based shape memory alloys with enhanced thermal stability and mechanical properties

    International Nuclear Information System (INIS)

    Cu-based shape memory alloys were developed in the 1960s. They show excellent thermoelastic martensitic transformation. However the problems in mechanical properties and thermal instability have inhibited them from becoming promising engineering alloys. A new Cu-Zn-Al-Mn-Zr Cu-based shape memory alloy has been developed. With the addition of Mn and Zr, the martensitic transformation behaviour and the grain size ca be better controlled. The new alloys demonstrates good mechanical properties with ultimate tensile strenght and ductility, being 460 MPa and 9%, respectively. Experimental results revealed that the alloy has better thermal stability, i.e. martensite stabilisation is less serious. In ordinary Cu-Zn-Al alloys, martensite stabilisation usually occurs at room temperature. The new alloy shows better thermal stability even at elevated temperature (∝150 C, >Af=80 C). A limited small amount of martensite stabilisation was observed upon ageing of the direct quenched samples as well as the step quenched samples. This implies that the thermal stability of the new alloy is less dependent on the quenching procedure. Furthermore, such minor martensite stabilisation can be removed by subsequent suitable parent phase ageing. The new alloy is ideal for engineering applications because of its better thermal stability and better mechanical properties. (orig.)

  14. Microstructural, mechanical and magnetic properties of shape memory alloy Ni55Mn23Ga22 thin films deposited by radio-frequency magnetron sputtering

    International Nuclear Information System (INIS)

    The near-stoichiometric Ni2MnGa ferromagnetic alloys are one of the smart materials, that are of a great interest when they are deposited as a thin film by r.f. sputtering. These thin films of shape memory alloys are prospective materials for micro and nanosystem applications. However, the properties of the shape memory polycrystalline thin films depend strongly on their structure and internal stress, which develop during the sputtering process as well as during the post-deposition annealing treatment. In this study, about 1 μm Ni55Mn23Ga22 thin films were deposited in the range 0,45 to 1,2 Pa of Ar pressure and P = 40 to 120 W. Their composition, crystallographic structure, internal stress and stress gradient, indentation modulus, hardness, deflection induced by magnetic field and magnetic properties were systematically studied as a function of the temperature of the silicon substrate ranging from 298 to 873 K and the vacuum annealing treatment at 873 K for 21,6 ks and 36 ks. A silicon wafer having a native amorphous thin SiOx buffer layer was used as a substrate. This substrate influences the microstructure of the films and blocks the diffusion process during the heat treatment. The crystal structure of the martensitic phase in each film was changed systematically from bct or 10 M or 14 M. In addition, the evolution of the mechanical properties such as mean stress, stress gradient, roughness, hardness and indentation modulus with the temperature (of substrate or of heat treatment) were measured and correlated to crystal structure and morphology changes. Moreover, it has been shown that it is necessary to associate a high temperature (873 K) annealing during a long time (21 ks and 36 ks) to obtain good ferromagnetic properties. Thus, for the well annealed films (36 ks at 873 K) the magnetostrain is about - 170 ppm for a magnetic field of 1 MA m-1 applied along the beams. As a conclusion, the response of free-standing magnetic shape memory films to a magnetic

  15. Microstructural and magnetic behavior of an equiatomic NiCoAlFe alloy prepared by mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Gómez-Esparza, C.D.; Baldenebro-López, F.J.; Santillán-Rodríguez, C.R.; Estrada-Guel, I.; Matutes-Aquino, J.A.; Herrera-Ramírez, J.M., E-mail: martin.herrera@cimav.edu.mx; Martínez-Sánchez, R.

    2014-12-05

    Highlights: • Equiatomic NiCoAlFe powder alloys were synthesized by mechanical alloying. • The nanocrystalline alloys were characterized after milled and annealed conditions. • In alloyed and annealed powders, only BCC and FCC structure phases were observed. • Magnetic properties are strongly affected by the phases formed after annealing. - Abstract: Equiatomic NiCoAlFe powder alloys were synthesized by mechanical alloying. The microstructural evolution of the mechanically alloyed powders at different times was followed with X-ray diffraction and scanning electron microscopy. The as-mechanically alloyed powders were subjected to a rapid annealing treatment at 1273 K and 1473 K during 3 min in vacuum. X-ray diffraction studies show the structure of both, the as-mechanically alloyed and annealed powders, consisted in a mixture of nanocrystalline simple phases (FCC + BCC). Crystallite size, after annealing, still remained in nanoscale. Coercivity increased due to the decrease in crystallite size and because of the defects caused by mechanical alloying in the as-mechanically alloyed samples; then coercivity decreased due to the phenomenon of random magnetic anisotropy and tended to stabilize with longer alloying times. A similar behavior was observed in annealed samples at 1273 K. However, random magnetic anisotropy was not observed after annealing at 1473 K because crystals with larger sizes were produced, and a steady increase in coercivity was observed.

  16. Properties and Applications of Nanocrystalline Alloys from Amorphous Precursors

    CERN Document Server

    Idzikowski, Bogdan; Miglierini, Marcel

    2005-01-01

    Metallic (magnetic and non-magnetic) nanocrystalline materials have been known for over ten years but only recent developments in the research into those complex alloys and their metastable amorphous precursors have created a need to summarize the most important accomplishments in the field. This book is a collection of articles on various aspects of metallic nanocrystalline materials, and an attempt to address this above need. The main focus of the papers is put on the new issues that emerge in the studies of nanocrystalline materials, and, in particular, on (i) new compositions of the alloys, (ii) properties of conventional nanocrystalline materials, (iii) modeling and simulations, (iv) preparation methods, (v) experimental techniques of measurements, and (vi) different modern applications. Interesting phenomena of the physics of nanocrystalline materials are a consequence of the effects induced by the nanocrystalline structure. They include interface physics, the influence of the grain boundaries, the aver...

  17. Thermophysical properties of Ni-5%Sn alloy melt

    Institute of Scientific and Technical Information of China (English)

    DAI; Fuping; CAO; Chongde; WEI; Bingbo

    2006-01-01

    The surface tension and specific heat of Ni-5%Sn alloy melt were measured by the oscillating drop method and the drop calorimetric method using electromagnetic levitation, respectively. The temperature coefficient of surface tension is 6.43×10-4 N·m-1K-1 within the temperature regime of 1464-1931 K. The enthalpy change was measured in the temperature range from 1461 to 1986 K, and the average specific heat was obtained as 43.03 J·mol-1K-1. Some other thermophysical properties, such as viscosity, solute diffusion coefficient, density, thermal diffusivity and thermal conductivity of this alloy melt, were derived based on the experimentally measured surface tension and specific heat. Using these thermophysical parameters, the relation between solute trapping and undercooling in rapidly solidified α-Ni was calculated, and the theoretical prediction shows a good agreement with experimental data.

  18. Surface modification of titanium and titanium alloys by ion implantation.

    Science.gov (United States)

    Rautray, Tapash R; Narayanan, R; Kwon, Tae-Yub; Kim, Kyo-Han

    2010-05-01

    Titanium and titanium alloys are widely used in biomedical devices and components, especially as hard tissue replacements as well as in cardiac and cardiovascular applications, because of their desirable properties, such as relatively low modulus, good fatigue strength, formability, machinability, corrosion resistance, and biocompatibility. However, titanium and its alloys cannot meet all of the clinical requirements. Therefore, to improve the biological, chemical, and mechanical properties, surface modification is often performed. In view of this, the current review casts new light on surface modification of titanium and titanium alloys by ion beam implantation.

  19. Magnetic properties of nanostructural γ-Ni-28Fe alloy

    Institute of Scientific and Technical Information of China (English)

    LIU Yin; QIN Xiao-ying; QIU Tai

    2006-01-01

    Nanostructural γ-Ni-28Fe alloy (nano γ-Ni-28Fe) was successfully prepared by mechanochemical alloying(MCA). The relationship between the microstructure and the synthesis conditions was investigated by using XRD, TEM, SEM as well as BET analyzer. The results show that nano γ-Ni-28Fe alloy is composed ora gamma phase (FCC structure). Its grain size is about 20 nm at reduction temperature below 600 ℃. The magnetic measurements indicate that the saturation magnetization ofnano γ-Ni-28Fe alloy to its decrease of the grain size and chemical composition in nano γ-Ni-28Fe alloy.

  20. Structural, Optical, and Magnetic Properties of Co Doped CdTe Alloy Powders Prepared by Solid-State Reaction Method

    Directory of Open Access Journals (Sweden)

    M. Rigana Begam

    2013-01-01

    Full Text Available Co doped CdTe powder samples were prepared by solid-state reaction method. In the present work effect of Co doping on structural, optical, and magnetic properties has been studied. X-ray diffraction studies confirm zinc blend structure for all the samples. The lattice parameter showed linear increase with the increase in Co content. The elemental constituents were characterized by EDAX. Optical studies showed the increase in band gap with increase in Co level. The samples were diluted magnetic semiconductors and exhibited clear hysteresis loop showing room temperature ferromagnetism as confirmed by vibrating sample magnetometer.

  1. Rheological properties and microstructure of the alloy AA 6063 obtained by semisolid processing using magnetohydrodynamic agitation and activated fusion induced by stress (SIMA process)

    International Nuclear Information System (INIS)

    The rheological behavior and the microstructural evolution of the alloy AA6063 submitted to two different processes, cold deformation and partial fusion, SIMA process and magnetohydrodynamic agitation during solidification, are studied. The evolution of the microstructure during the isothermal maintenance was studied in order to verify if the classic Ostwald ripening, growth and coalescence mechanisms are applicable to alloys made by these processes. The rheological properties were evaluated using a compression rheometer between parallel plates with data on time and position collected digitally. The procedure included the full metallographic characterization of the samples for SIMA and MHD processes as well as the study of the microstructural evolution during isothermal maintenance at various solid fractions. Compression tests were performed of short cylinders extracted from cast ingots with a dendritic microstructure, cold deformed material and obtained by the MHD process. These test pieces were tested at different solid fractions under constant load, to determine the equation that governs the rheological behavior of the material in semisolid state, according to two parameters of the Ostwald-de-Waele power law. Based on the results obtained, the morphology of the primary phase in the microstructure is deduced to be highly relevant to its rheological behavior. A globular microstructure has the typical behavior of a fluid when it is formed in a semi-solid state, but this does not hold true for a cast dendritic microstructure. The mechanisms that operate in the microstructural evolution during the isothermal maintenance were proven by metallographic analysis. The differences in rheological behavior are possibly due to the morphological differences of the AlFeSI intermetallics. These intermetallics are located in the inter dendritic zones and prepare the formation of the incipient liquid phase and the effective amount of liquid that participates in the deformation

  2. Mechanical Properties and Transformation Behavior of NiTiNb Shape Memory Alloys

    Institute of Scientific and Technical Information of China (English)

    Liu Wei; Zhao Xinqing

    2009-01-01

    NiTiNb shape memory alloys have attracted much attention in pipe coupling or sealing system because of their large transformation hysteresis upon a proper pre-deformation. In order to clarify the effects of adding Nb on the mechanical properties as well as the transformation behavior of NiTiNb shape memory alloys, Ni_(47)Ti_(44)Nb_9 and Ni_(49.8)Ti_(45.2)Nb_5 alloys with different microstructures but with similar martensitic transformation start temperature, are prepared. Comparative studies on the microstructures, mechanical properties and transformation characteristics are conducted by means of scanning electron microscopy (SEM), phase transformation measurements and mechanical property tests. It is found that Ni_(47)Ti_(44)Nb_9 and Ni49.8Ti45.2Nb5 alloys possess similar transformation hysteresis in the as-annealed state. However, the presence of Nb and its status exerts important effects on the mechanical properties, especially the yield strength and the yield behavior of the alloys. Ni_(49.8)Ti_(45.2)Nb_5 alloy exhibits remarkable increase in the yield strength than the Ni_(47)Ti_(44)Nb_9 alloy. The transformation hysteresis of both alloys under pre-deformation is characterized and the relative mechanism is discussed.

  3. Effect of process control agent on the porous structure and mechanical properties of a biomedical Ti-Sn-Nb alloy produced by powder metallurgy.

    Science.gov (United States)

    Nouri, A; Hodgson, P D; Wen, C E

    2010-04-01

    The influence of different amounts and types of process control agent (PCA), i.e., stearic acid and ethylene bis-stearamide, on the porous structure and mechanical properties of a biomedical Ti-16Sn-4Nb (wt.%) alloy was investigated. Alloy synthesis was performed on elemental metal powders using high-energy ball milling for 5h. Results indicated that varying the PCA content during ball milling led to a drastic change in morphology and particle-size distribution of the ball-milled powders. Porous titanium alloy samples sintered from the powders ball milled with the addition of various amounts of PCA also revealed different pore morphology and porosity. The Vickers hardness of the sintered titanium alloy samples exhibited a considerable increase with increasing PCA content. Moreover, the addition of larger amounts of PCA in the powder mixture resulted in a significant increase in the elastic modulus and peak stress for the sintered porous titanium alloy samples under compression. It should also be mentioned that the addition of PCA introduced contamination (mainly carbon and oxygen) into the sintered porous product.

  4. Evolution of structure, microstructure and hyperfine properties of nanocrystalline Fe{sub 50}Co{sub 50} powders prepared by mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Akkouche, K. [LMMC, M' hamed Bougara University, Boumerdes 35000 (Algeria); Guittoum, A., E-mail: guittoum@yahoo.fr [Nuclear Research Centre of Algiers, 2 Bd Frantz Fanon, BP399 Alger-Gare, Algiers (Algeria); Boukherroub, N. [LMMC, M' hamed Bougara University, Boumerdes 35000 (Algeria); Souami, N. [Nuclear Research Centre of Algiers, 2 Bd Frantz Fanon, BP399 Alger-Gare, Algiers (Algeria)

    2011-11-15

    Nanostructured Fe{sub 50}Co{sub 50} powders were prepared by mechanical alloying of Fe and Co elements in a vario-planetary high-energy ball mill. The structural properties, morphology changes and local iron environment variations were investigated as a function of milling time (in the 0-200 h range) by means of X-ray diffraction, scanning electron microscopy (SEM), energy dispersive X-ray analysis and {sup 57}Fe Moessbauer spectroscopy. The complete formation of bcc Fe{sub 50}Co{sub 50} solid solution is observed after 100 h milling. As the milling time increases from 0 to 200 h, the lattice parameter decreases from 0.28655 nm for pure Fe to 0.28523 nm, the grain size decreases from 150 to 14 nm, while the meal level of strain increases from 0.0069% to 1.36%. The powder particle morphology at different stages of formation was observed by SEM. The parameters derived from the Moessbauer spectra confirm the beginning of the formation of Fe{sub 50}Co{sub 50} phase at 43 h of milling. After 200 h of milling the average hyperfine magnetic field of 35 T suggests that a disordered bcc Fe-Co solid solution is formed. - Highlights: > Nanostructured Fe{sub 50}Co{sub 50} powders were successfully prepared by mechanical alloying process. > Final average grain size value achieved after 200 h of milling was 14 nm. > For the longest milling time the majority of particle grains observed by SEM exhibits a round shape with small diameter.

  5. Influence of the Chemical Composition on Electrical Conductivity and Mechanical Properties of the Hypoeutectic Al-Si-Mg Alloys

    OpenAIRE

    Dybowski B.; Szymszal J.; Poloczek Ł.; Kiełbus A.

    2016-01-01

    Due to low density and good mechanical properties, aluminium alloys are widely applied in transportation industry. Moreover, they are characterized by the specific physical properties, such as high electrical conductivity. This led to application of the hypoeutectic Al-Si-Mg alloys in the power generation industry. Proper selection of the alloys chemical composition is an important stage in achievement of the demanded properties. The following paper presents results of the research on the inf...

  6. Structural and magnetic properties of Fe{sub 60}Al{sub 40} alloys prepared by means of a magnetic mill

    Energy Technology Data Exchange (ETDEWEB)

    Bernal-Correa, R. [Laboratorio de Magnetismo y Materiales Avanzados, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Colombia, Manizales (Colombia); Rosales-Rivera, A., E-mail: arosalesr@unal.edu.c [Laboratorio de Magnetismo y Materiales Avanzados, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Colombia, Manizales (Colombia); Pineda-Gomez, P. [Laboratorio de Magnetismo y Materiales Avanzados, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Colombia, Manizales (Colombia); Universidad de Caldas, Manizales (Colombia); Salazar, N.A. [Laboratorio de Magnetismo y Materiales Avanzados, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Colombia, Manizales (Colombia)

    2010-04-16

    A study on synthesis, structural and magnetic characterization of Fe{sub 60}Al{sub 40} (at.%) alloys prepared by means of mechanical alloying process is presented. The mechanical alloying was performed using a milling device with magnetically controlled ball movement (Uni-Ball-Mill 5 equipment) at several milling times. The characterization was carried out via X-ray diffraction (XRD), scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM). The effects of milling time on the structural state, morphological evolution and magnetic behaviour of the Fe{sub 60}Al{sub 40} (at.%) alloys are discussed. Besides, in this current study we emphasize the result that indicating a ferro-para-ferromagnetic transition from a correlation between X-ray diffraction and magnetization data.

  7. Refining U-Zr-Nb alloys by remelting

    Energy Technology Data Exchange (ETDEWEB)

    Aguiar, B.M.; Kniess, C.T.; Riella, H.G., E-mail: bmaguiar@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Ferraz, W.B. [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2011-07-01

    The high density U-Zr-Nb and U-Nb uranium-based alloys can be employed as nuclear fuel in a PWR reactor due to their high density and nuclear properties. These alloys can stabilize the gamma phase, however, according to TTT diagrams, at the working temperature of a PWR reactor, all gamma phase transforms to {alpha}'' phase in a few hours. To avoid this kind of transformation during the nuclear reactor operation, the U-Zr-Nb alloy and U-Nn are used in {alpha}'' phase. The stability of {alpha}'' phase depends on the alloy composition and cooling rate. The alloy homogenization has to be very effective to eliminate precipitates rich in Zr and Nb to avoid changes in the alloying elements contents in the matrix. The homogenization was obtained by remelting the alloy and keeping it in the liquid state for enough time to promote floating of the precipitates (usually carbides, less dense) and leaving the matrix free of precipitates. However, this floating by density difference may result in segregation between the alloying elements (Nb and Zr, at the top) and uranium (at the bottom). The homogenized alloys were characterized in terms of metallographic techniques, optical microscopy, scanning electronic microscopy, EDS and X-ray diffraction. In this paper, it is shown that the contents of Zr and Nb at the bottom and at the top of the matrix are constant. (author)

  8. Electronic tuning of the transport properties of off-stoichiometric PbxSn1−xTe thermoelectric alloys by Bi2Te3 doping

    International Nuclear Information System (INIS)

    The recent energy demands affected by the dilution of conventional energy resources and the growing awareness of environmental considerations had motivated many researchers to seek for novel renewable energy conversion methods. Thermoelectric direct conversion of thermal into electrical energies is such a method, in which common compositions include IV-VI semiconducting compounds (e.g., PbTe and SnTe) and their alloys. For approaching practical thermoelectric devices, the current research is focused on electronic optimization of off-stoichiometric p-type PbxSn1−xTe alloys by tuning of Bi2Te3 doping and/or SnTe alloying levels, while avoiding the less mechanically favorable Na dopant. It was shown that upon such doping/alloying, higher ZTs, compared to those of previously reported undoped Pb0.5Sn0.5Te alloy, were obtained at temperatures lower than 210–340 °C, depending of the exact doping/alloying level. It was demonstrated that upon optimal grading of the carrier concentration, a maximal thermoelectric efficiency enhancement of ∼38%, compared to that of an undoped material, is expected

  9. Influence of Electric Field on Mechanical Properties of Al-Li Alloy Containing Cerium and Electronic Mechanism

    Institute of Scientific and Technical Information of China (English)

    刘兵; 陈铮; 王永欣; 王西宁

    2001-01-01

    The effect of electric field on the mechanical properties and microstructure of Al-Li alloy containing Ce was investigated, and mechanism was discussed. The experimental results show that the ductility of the alloy is enhanced by the electric field. The fracture features are changed and the precipitates are dispersed under the effect of the electric field. The mechanism discussion reveals that the effects of the electric field on the alloy are due to the change of the electron density in the alloy.

  10. Tensile Properties and Fracture Behavior of Aluminum Alloy Foam Fabricated from Die Castings without Using Blowing Agent by Friction Stir Processing Route

    Directory of Open Access Journals (Sweden)

    Yoshihiko Hangai

    2014-03-01

    Full Text Available Al foam has been used in a wide range of applications owing to its light weight, high energy absorption and high sound insulation. One of the promising processes for fabricating Al foam involves the use of a foamable precursor. In this study, ADC12 Al foams with porosities of 67%–78% were fabricated from Al alloy die castings without using a blowing agent by the friction stir processing route. The pore structure and tensile properties of the ADC12 foams were investigated and compared with those of commercially available ALPORAS. From X-ray computed tomography (X-ray CT observations of the pore structure of ADC12 foams, it was found that they have smaller pores with a narrower distribution than those in ALPORAS. Tensile tests on the ADC12 foams indicated that as their porosity increased, the tensile strength and tensile strain decreased, with strong relation between the porosity, tensile strength, and tensile strain. ADC12 foams exhibited brittle fracture, whereas ALPORAS exhibited ductile fracture, which is due to the nature of the Al alloy used as the base material of the foams. By image-based finite element (FE analysis using X-ray CT images corresponding to the tensile tests on ADC12 foams, it was shown that the fracture path of ADC12 foams observed in tensile tests and the regions of high stress obtained from FE analysis correspond to each other. Therefore, it is considered that the fracture behavior of ADC12 foams in relation to their pore structure distribution can be investigated by image-based FE analysis.

  11. Phase stability, deformation mechanisms, and mechanical properties of Nb-Al-Ti alloys

    International Nuclear Information System (INIS)

    The phase stability, deformation mechanisms and mechanical properties of two alloys based on Nb3Al containing additions of Ti have been studied. These two alloys, with nominal compositions (in at.%) of Nb-15Al-10Ti (alloy 1) and Nb-15Al-40Ti (alloy 2), have the B2 crystal structure in as cast form. The ALCHEMI technique has been employed to assess qualitatively the distribution of atom types over the two sublattices of the B2 compounds. It is found that Ti and Al occupy different sublattices in alloy 2. Heat-treatment of alloy 1 at 1,100 C results in the precipitation of an A15 phase in the B2 matrix. Annealing at 900 C for short time introduces an w-phase. Prolonged annealing of alloy 1 at 700 C reveals the presence of an orthorhombic phase. The same orthorhombic phase is also found to exist between 800 and 1,000 C in alloy 2. Specific orientation relationships exist between the matrix phase and precipitates. The yield strength in compression of Alloy 1 and 2 were determined at various temperatures. Alloy 1 is strong compared to superalloy IN 718 over a range of temperatures up to 950 C. Both alloys with the B2 crystal structure are deformed by one or more of the following slip systems, namely (110), (112) and (123). Dislocations with Burgers vector, b, given by b= are present in the form of dissociated superpartial pairs, each with b=1/2. The inherent ductility of both alloys is indicated by the active slip systems and illustrated by 20% elongation to failure obtained in alloy 2 under room temperature tensile test. A trend of increasing tensile yield stress with increasing antiphase domain size was found. No evidence of interaction between dislocations and antiphase boundaries has been found to account for this increase of strength

  12. Structure and Property of AgLaY Alloy

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The structure of RE-Ag alloy was observed and analyzed using electron probe. The property changes of the alloy containing two rare earth elements AgLaY during cold forming and the high temperature softening-resistance during annealing were studied using Vickers hardness tester. The distribution and action of the rare earth elements in Ag-alloy were also analyzed. Experimental results show that AgLaY alloy has more remarkable work-hardening effect than AgLa and pure silver, and it also has better thermal-resistance. The effects of RE elements, La and Y, on the properties of Ag-alloy are attributable to their symbiotic distribution and complementary function. Because of the common properties of La and Y as RE elements, they have the completely similar distribution in Ag-alloy. At the same time, La and Y make full use of complementary role in the alloy since they belong to different periods in periodic table and have differences in atomic structure and properties.

  13. Microstructure and properties of laser surface alloyed PM austenitic stainless steel

    Directory of Open Access Journals (Sweden)

    Z. Brytan

    2010-05-01

    Full Text Available Purpose: The purpose of this paper is to analyse the effect of laser surface alloying with chromium on the microstructural changes and properties of vacuum sintered austenitic stainless steel type AISI 316L (EN 1.4404.Design/methodology/approach: Surface modification of AISI 316L sintered austenitic stainless steel was carried out by laser surface alloying with chromium powder using high power diode laser (HPDL. The influence of laser alloying conditions, both laser beam power (between 0.7 and 2.0 kW and powder feed rate (1.0-4.5 g/min at constant scanning rate of 0.5m/min on the width of alloyed surface layer, penetration depth, microstructure evaluated by LOM, SEM x-ray analysis, surface roughness and microhardness were presented.Findings: The microstructures of Cr laser alloyed surface consist of different zones, starting from the superficial zone rich in alloying powder particles embedded in the surface; these particles protrude from the surface and thus considerably increase the surface roughness. Next is alloyed zone enriched in alloying element where ferrite and austenite coexists. The following transient zone is located between properly alloyed material and the base metal and can be considered as a very narrow HAZ zone. The optimal microstructure homogeneity of Cr alloyed austenitic stainless steel was obtained for powder feed rate of 2.0 and 4.5 g/min and laser beam power of 1.4 kW and 2 kW.Practical implications: Laser surface alloying can be an efficient method of surface layer modification of sintered stainless steel and by this way the surface chromium enrichment can produce microstructural changes affecting mechanical properties.Originality/value: Application of high power diode laser can guarantee uniform heating of treated surface, thus uniform thermal cycle across treated area and uniform penetration depth of chromium alloyed surface layer.

  14. Electronic properties of liquid Hg-In alloys : Ab-initio molecular dynamics study

    Science.gov (United States)

    Sharma, Nalini; Thakur, Anil; Ahluwalia, P. K.

    2016-05-01

    Ab-initio molecular dynamics simulations are performed to study the structural properties of liquid Hg-In alloys. The interatomic interactions are described by ab-initio pseudopotentials given by Troullier and Martins. Three liquid Hg-In alloys (Hg10In90, Hg30In70,. Hg50In50, Hg70In30, and Hg90Pb10) at 299 K are considered. The calculated results for liquid Hg (l-Hg) and lead (l-In) are also drawn. Along with the calculated results of considered five liquid alloys of Hg-In alloy. The results obtained from electronic properties namely total density of state and partial density of states help to find the local arrangement of Hg and In atoms and the presence of liquid state in the considered five alloys.

  15. Platinum-Iridium Alloy Films Prepared by MOCVD

    Institute of Scientific and Technical Information of China (English)

    WEI Yan; CHEN Li; CAI Hongzhong; ZHENG Xu; YANG Xiya; HU Changyi

    2012-01-01

    Platinum-Iridium alloy films were prepared by MOCVD on Mo substrate using metal-acetylacetonate precursors.Effects of deposition conditions on composition,microstructure and mechanical properties were determined.In these experimental conditions,the purities of films are high and more than 99.0%.The films are homogeneous and monophase solid solution of Pt and Ir.Weight percentage of platinum are much higher than iridium in the alloy.Lattice constant of the alloy changes with the platinum composition.Iridium composition showing an up-down-up trend at the precursor temperature of 190~230℃ and the deposition temperature at 400~550℃.The hardness of Pt-Ir alloys prepared by MOCVD is three times more than the alloys prepared by casting.

  16. Surface Modification of a MCFC Anode by Electrochemical Alloying

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Considering the properties of the valve metal alloys with specific corrosion resistance and electrocatalytic ac tivity, an investigation was made to examine if nickel-niobium alloy could serve as the anode material for molten carbo nate fuel cell (MCFC). An attempt was made to produce nickel-niobium surface alloy by an electrochemical process in the molten fluorides and to testify its performance required by the MCFC anode. Experimental results indicated that the corrosion resistance as well as polarization performance of the nickel electrode was improved by the surface alloying.As far as the corrosion resistance and polarization performance is concerned, the nickel-niobium surface alloy can be considered as a candidate material for the anode of MCFC.

  17. Tribological properties of laser cladding TiB2 particles reinforced Ni-base alloy composite coatings on aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    Long He; Ye-Fa Tan; Xiao-Long Wang; Qi-Feng Jing; Xiang Hong

    2015-01-01

    To improve the wear resistance of aluminum alloy frictional parts,TiB2 particles reinforced Ni-base alloy composite coatings were prepared on aluminum alloy 7005 by laser cladding.The microstructure and tribological properties of the composite coatings were investigated.The results show that the composite coating contains the phases of NiAl,Ni3Al,Al3Ni2,TiB2,TiB,TiC,CrB,and Cr23C6.Its microhardness is HV0.5 855.8,which is 15.4 % higher than that of the Ni-base alloy coating and is 6.7 times as high as that of the aluminum alloy.The friction coefficients of the composite coatings are reduced by 6.8 %-21.6 % and 13.2 %-32.4 % compared with those of the Ni-base alloy coatings and the aluminum alloys,while the wear losses are 27.4 %-43.2 % less than those of the Ni-base alloy coatings and are only 16.5 %-32.7 % of those of the aluminum alloys at different loads.At the light loads ranging from 3 to 6 N,the calculated maximum contact stress is smaller than the elastic limit contact stress.The wear mechanism of the composite coatings is micro-cutting wear,but changes into multi-plastic deformation wear at 9 N due to the higher calculated maximum contact stress than the elastic limit contact stress.As the loads increase to 12 N,the calculated flash temperature rises to 332.1 ℃.The composite coating experiences multi-plastic deformation wear,micro-brittle fracture wear,and oxidative wear.

  18. Structure and mechanical properties of Mg-Si alloys at elevated temperatures

    OpenAIRE

    L. Čížek; A. Hanus; O. Blahož; T. Tański; L.A. Dobrzański; M. Praźmowski; L. Pawlica

    2009-01-01

    Purpose: of this paper is to extend a complex evaluation of magnesium alloys which requires very often knowledge of structure and mechanical properties at elevated temperatures. These properties are connected with microstructure that is influenced by metallurgical and technological factors and exploitation conditions. Presented knowledge expresses very important information for design and exploitation of these alloys.Design/methodology/approach: The optical and scanning electron microscopy me...

  19. Adhesive Bonding of Aluminium Alloy A5754 by Epoxy Resins

    Directory of Open Access Journals (Sweden)

    Ivan Michalec

    2013-01-01

    Full Text Available Joining thin sheets of aluminium and its alloys is a promising area in the field of joining materials. Nowadays, joining methods that do not melt the material itself are increasingly being utilised. This paper deals with adhesive bonding of aluminium alloy A5754 by two-component epoxy resins. Theresults show that joints bonded by Hysol 9466 have appropriate mechanical properties, but that joints bonded by Hysol 9492 have better thermal stability.

  20. Influence of thermomechanical treatment on microstructure and properties of electroslag remelted Cu–Cr–Zr alloy

    International Nuclear Information System (INIS)

    Highlights: • Effect of ESR process on microstructure of Cu–Cr–Zr alloy was investigated. • The hardness, strength and electrical conductivity are sensitive to thermomechanical treatment. • The microstructure of the alloy can be optimized for obtaining the best combination of mechanical and electrical properties. - Abstract: Effect of thermomechanical treatment (TMT) on aging behavior of electroslag remelted Cu–Cr–Zr alloy was investigated. The relationship between microstructure, mechanical and electrical properties was clarified using hardness, tensile and electrical conductivity testing methods and optical and scanning electron microscopy techniques. The results showed that an appropriate processing and aging treatment may improve the properties of the alloy due to the formation of fine, dispersive and coherent precipitates within the matrix. Indeed, the optimum condition for electrical conductivity and mechanical properties was obtained after cold working of 40% followed by aging at 500 °C for 150 min

  1. Formation of Sn-M (M=Fe, Al, Ni) alloy nanoparticles by DC arc-discharge and their electrochemical properties as anodes for Li-ion batteries

    Science.gov (United States)

    Gao, Song; Huang, Hao; Wu, Aimin; Yu, Jieyi; Gao, Jian; Dong, Xinglong; Liu, Chunjing; Cao, Guozhong

    2016-10-01

    A direct current arc-discharge method was applied to prepare the Sn-M (M=Fe, Al, Ni) bi-alloy nanoparticles. Thermodynamic is introduced to analyze the energy circumstances for the formation of the nanoparticles during the physical condensation process. The electrochemical properties of as-prepared Sn-M alloy nanoparticles are systematically investigated as anodes of Li-ion batteries. Among them, Sn-Fe nanoparticles electrode exhibits high Coulomb efficiency (about 71.2%) in the initial charge/discharge (257.9 mA h g-1/366.6 mA h g-1) and optimal cycle stability (a specific reversible capacity of 240 mA h g-1 maintained after 20 cycles) compared with others. Large differences in the electrochemical behaviors indicate that the chemical composition and microstructure of the nanoparticles determine the lithium-ion storage properties and the long-term cyclic stability during the charge/discharge process.

  2. The properties of silicon alloyed ferritic ductile irons

    OpenAIRE

    Z. Glavas; A. Strkalj; A. Stojakovic

    2016-01-01

    In this paper the influence of silicon content of 3,1 to 5,4 wt. % on the tensile properties, hardness and impact energy of ferritic ductile iron was analysed. It was found that silicon strengthens the ferrite, resulting in an increase in yield strength and tensile strength with increasing silicon content up to 4,22 wt. %. Elongation and impact energy decreases and the hardness increases with increasing silicon content. Since ferritic ductile irons alloyed and strengthened by silicon have a h...

  3. Microstructures and properties of low-alloy fire resistant steel

    Indian Academy of Sciences (India)

    Bimal Kumar Panigrahi

    2006-02-01

    Microstructures and properties of weldable quality low-alloy fire resistant structural steels (YS: 287–415 MPa) and TMT rebar (YS: 624 MPa) have been investigated. The study showed that it is possible to obtain two-thirds of room temperature yield stress at 600°C with 0.20–0.25% Mo and 0.30–0.55% Cr in low carbon hot rolled structural steel. Microalloying the Cr–Mo steel by niobium or vanadium singly or in combination resulted in higher guaranteed elevated temperature yield stress (250–280 MPa). The final rolling temperature should be maintained above austenite recrystallization stop temperature (∼ 900° C) to minimize dislocation hardening. In a quenched and self-tempered 600 MPa class TMT reinforcement bar steel (YS: 624 MPa), low chromium (0.55%) addition produced the requisite yield stress at 600°C. The low-alloy fire resistant steel will have superior thermal conductivity up to 600°C (> 30 W/m.k) compared to more concentrated alloys.

  4. Mechanical properties of tantalum-niobium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Chamdawalla, N; Ettmayer, P.; Femboeck, J.; Aschenbrenner, W.; Bildstein, H.

    1986-02-01

    Young's modulus and shear modulus have been measured on fully dense polycrystalline sintered (swaged and forged and recrystallized) tantalum-niobium alloys. Young's modulus decreases steadily and monotonously from pure tantalum to pure niobium. Ultimate tensile strength values have been measured at 6 different temperatures between 20 and 1500/sup 0/ C. No significant solution hardening effect could be observed. Room temperature and hot hardness of the alloys were evaluated. (orig.).

  5. Effect of melt conditioning on heat treatment and mechanical properties of AZ31 alloy strips produced by twin roll casting

    International Nuclear Information System (INIS)

    In the present investigation, magnesium strips were produced by twin roll casting (TRC) and melt conditioned twin roll casting (MC-TRC) processes. Detailed optical microscopy studies were carried out on as-cast and homogenized TRC and MC-TRC strips. The results showed uniform, fine and equiaxed grain structure was observed for MC-TRC samples in as-cast condition. Whereas, coarse columnar grains with centreline segregation were observed in the case of as-cast TRC samples. The solidification mechanisms for TRC and MC-TRC have been found completely divergent. The homogenized TRC and MC-TRC samples were subjected to tensile test at elevated temperature (250–400 °C). At 250 °C, MC-TRC sample showed significant improvement in strength and ductility. However, at higher temperatures the tensile properties were almost comparable, despite of TRC samples having larger grains compared to MC-TRC samples. The mechanism of deformation has been explained by detailed fractures surface and sub-surface analysis carried out by scanning electron and optical microscopy. Homogenized MC-TRC samples were formed (hot stamping) into engineering component without any trace of crack on its surface. Whereas, TRC samples cracked in several places during hot stamping process

  6. The mechanical properties and microstructure of the bionic alloy-ceramic laminated composite

    International Nuclear Information System (INIS)

    Highlights: → The bionic alloy-ceramic laminated composite was fabricated by EB-PVD. → Mechanical properties and microstructure of laminated composite were investigated. → Laminated composite was heat treated in order to improve the tensile strength. -- Abstract: In the present work, the bionic alloy-ceramic laminated composite was fabricated by electron beam-physical vapor deposition method. The ingots of Ni-20Co-12Cr-4Al (wt.%) and ZrO2-8 mol%Y2O3 were used as the sources of the alloy layer and ceramic layer, respectively. The laminated composite was generally destroyed within the ceramic layer when the interlaminar strength was determined, which revealed that the excellent interface bonding between the ceramic layer and the alloy layer. The obvious diffusion interfaces between the ceramic and alloy layers were readily detected, which was favorable to the mechanical properties of the laminated composite. In the heat treatment process, the diffusion of the flaws within the ceramic layer and/or alloy layer to the interface between the ceramic layer and alloy layer was easier compared with the occurrence of interlaminar diffusion. It was confirmed by the X-ray diffractometer that the reaction of the ceramic layer with alloy layer was simple physical diffusion. The tensile strength of the laminated composite increased first and then decreased as the heat treatment time increased, which was attributed to the mutual reaction of the increase in the relative density with the formation of the flaws located at the interface.

  7. Effect of deposition parameters on mechanical properties of TiN films coated on 2A12 aluminum alloys by arc ion plating (AIP)

    Institute of Scientific and Technical Information of China (English)

    AWAD Samir Hamid; QIAN Han-cheng

    2005-01-01

    TiN films were deposited on 2A12 aluminum alloy by arc ion plating (AIP). The Vickers hardness of the films deposited at different bias voltages and different nitrogen gas pressures, and that of the substrate were measured. The surface roughness of the TiN films diposited at -30 V and -80 V respectively and at different nitrogen gas pressure was measured also. The mass loss of TiN films deposited at 0 V, -30 V and -80 V respectively were analyzed in dry sand rubber wheel abrasive wear tests and wet ones in comparison with uncoated Al alloy and austenitic stainless steel (AISI 316L). It is revealed that the highest hardness of the TiN film is obtained at a bias voltage of -30 V and a N2 gas pressure of 0.5 Pa. The surface roughness of the film is larger at -80 V than that at -30 V and reduces as the increase of the N2 gas pressure. The mass loss of TiN-film coated 2A12 aluminum alloy is remarkably less than that of uncoated Al alloy and also that of AISI 316L, which indicates that the abrasive wear rate is greatly reduced by the application of TiN coating. TiN coating deposited by arc ion plating (AIP) technique on aluminum alloy can be a potential coating for machine parts requiring preciseness and lightness.

  8. Processing TiAl-Based Alloy by Elemental Powder Metallurgy

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    TiAl-based alloys with various compositions (including Ti-48Al, Ti-47Al-2Cr-2Nb, Ti-47Al-2Cr-2Nb-0.2B and Ti-47Al-3Cr, in mole fraction) had been prepared by elemental powder metallurgy (EPM). The results have shown that the density of the prepared Ti-48Al alloy increases with increasing hot pressing temperature up to 1300℃. The Ti-48Al alloy microstructure mainly consisted of island-like Ti3Al phase and TiAl matrix at hot pressing temperature below 1300℃, however, coarse α2/γlamellar colonies and γ grains appeared at 1400℃. It has also indicated that the additions of elemental Cr and B can refine the alloy microstructure. The main microstructural inhomogeneity in EPM TiAl-based alloys was the island-like α2 phase or the aggregate of α2/γ lamellar colony, and such island-like structure will be inherited during subsequent heat treatment in (α+γ) field. Only after heat treatment in α field would this structure be eliminated. The mechanical properties of EPM TiAl-based alloys with various compositions were tested, and the effect of alloy elements on the mechanical properties was closely related to that of alloy elements on the alloy microstructures. Based on the above results, TiAl-based alloy exhaust valves were fabricated by elemental powder metallurgy and diffusion joining. The automobile engine test had demonstrated that the performance of the manufactured valves was very promising for engine service.

  9. Non-alloyed Ni3Al based alloys – preparation and evaluation of mechanical properties

    Directory of Open Access Journals (Sweden)

    J. Malcharcziková

    2013-07-01

    Full Text Available The paper reports on the fabrication and mechanical properties of Ni3Al based alloy, which represents the most frequently used basic composition of nickel based intermetallic alloys for high temperature applications. The structure of the alloy was controlled through directional solidification. The samples had a multi-phase microstructure. The directionally solidified specimens were subjected to tensile tests with concurrent measurement of acoustic emission (AE. The specimens exhibited considerable room temperature ductility before fracture. During tensile testing an intensive AE was observed.

  10. Charge injection properties of iridium oxide films produced on Ti-6Al-4V alloy substrates by ion-beam mixing techniques

    Energy Technology Data Exchange (ETDEWEB)

    Williams, J.M. (Oak Ridge National Lab., TN (United States)); Lee, I-S.; Buchanan, R.A. (Tennessee Univ., Knoxville, TN (United States))

    1991-10-01

    The charge injection capabilities of iridium oxide films, as produced on Ti6Al-4V alloy substrates by ion beam mixing techniques, have been investigated. Iridium oxide is a valence change oxide, and therefore has high values of charge injection density upon voltage cycling in electrolytes. Because of this property, iridium oxide films are useful as working elements in neural prostheses. Iridium films of three thicknesses, produced by sputter deposition followed by ion beam mixing, were tested in cyclic voltammetry out to 1000 cycles or more. Two surface preparations, mechanical polishing and an acid passivation treatment, were also used as controls. Surface analysis was primarily by Rutherford backscattering spectrometry. Both the ion- beam mixing and the acid pretreatment increased the lifetimes of films, in comparison with the mechanically polished standards. Reductions in charge injection capability, when they occurred, were attributed to loss of Ir from the films, and there was a close correlation between the charge injection density and the Ir inventory. 13 refs., 5 figs.

  11. New developments on optimizing properties of high-Zn aluminium cast alloys

    Science.gov (United States)

    Krajewski, W. K.; Buras, J.; Krajewski, P. K.; Greer, A. L.; Schumacher, P.; Haberl, K.

    2016-07-01

    Foundry alloys with Al-based matrices have a wide range of uses in today's global economy and there is a high demand for castings of Al alloys, including Al-Zn alloys. In this paper, investigations on the grain refinement of high-Zn aluminium cast alloys are presented. Aluminium alloys with relatively high zinc content have a tendency to be coarse-grained, especially in the case of castings with low cooling rates such as are found in sand moulds. The coarse-grained structure degrades the plasticity, specifically the elongation. Therefore, for aluminium alloys of high (10-30 wt.%) zinc content, inoculation is attractive, aiming to break up the primary dendrites of the a-phase solid solution of zinc in aluminium. Such dendrites are the principal microstructural component in these alloys. On the other hand, a finer grain structure usually reduces the damping (e.g. as measured by attenuation of ultrasound) in these alloys. In the present investigations, a binary sand-cast Al-20 wt.% Zn alloy was inoculated with different additions of AlTi3C0.15 (TiCAl) and ZnTi-based master alloys. The sand-cast samples were subjected to mechanical-property measurements (tensile strength and elongation), image analysis to determine grain size, and measurements of the attenuation of 1 MHz ultrasound. It is found that both of the master alloys used cause significant refinement of the a-AlZn primary dendrites and change their morphology from linear-branched to semi-globular, increase the elongation by about 40%, and decrease the attenuation coefficient by about 25% in comparison with the initial alloy without inoculation.

  12. Influence of volume magnetostriction on the thermodynamic properties of Ni-Mn-Ga shape memory alloys

    Science.gov (United States)

    Kosogor, Anna; L'vov, Victor A.; Cesari, Eduard

    2015-10-01

    In the present article, the thermodynamic properties of Ni-Mn-Ga ferromagnetic shape memory alloys exhibiting the martensitic transformations (MTs) above and below Curie temperature are compared. It is shown that when MT goes below Curie temperature, the elastic and thermal properties of alloy noticeably depend on magnetization value due to spontaneous volume magnetostriction. However, the separation of magnetic parts from the basic characteristics of MT is a difficult task, because the volume magnetostriction does not qualitatively change the transformational behaviour of alloy. This problem is solved for several Ni-Mn-Ga alloys by means of the quantitative theoretical analysis of experimental data obtained in the course of stress-strain tests. For each alloy, the entropy change and the transformation heat evolved in the course of MT are evaluated, first, from the results of stress-strain tests and, second, from differential scanning calorimetry data. For all alloys, a quantitative agreement between the values obtained in two different ways is observed. It is shown that the magnetic part of transformation heat exceeds the non-magnetic one for the Ni-Mn-Ga alloys undergoing MTs in ferromagnetic state, while the elevated values of transformation heat measured for the alloys undergoing MTs in paramagnetic state are caused by large MT strains.

  13. Influence of volume magnetostriction on the thermodynamic properties of Ni-Mn-Ga shape memory alloys

    Energy Technology Data Exchange (ETDEWEB)

    Kosogor, Anna [National University of Science and Technology “MISiS,” Moscow 119049 (Russian Federation); Institute of Magnetism, 36-b, Vernadsky Str., Kyiv 03142 (Ukraine); Donetsk Institute for Physics and Engineering, Kyiv 03028 (Ukraine); L' vov, Victor A. [Institute of Magnetism, 36-b, Vernadsky Str., Kyiv 03142 (Ukraine); Faculty of Radiophysics, Electronics and Computer Systems, Taras Shevchenko University, Glushkov Str. 4G, Kyiv 01601 (Ukraine); Departament de Fisica, Universitat de les Illes Balears, Ctra. de Valldemossa, km 7.5, 07122 Palma de Mallorca (Spain); Cesari, Eduard [Departament de Fisica, Universitat de les Illes Balears, Ctra. de Valldemossa, km 7.5, 07122 Palma de Mallorca (Spain)

    2015-10-07

    In the present article, the thermodynamic properties of Ni-Mn-Ga ferromagnetic shape memory alloys exhibiting the martensitic transformations (MTs) above and below Curie temperature are compared. It is shown that when MT goes below Curie temperature, the elastic and thermal properties of alloy noticeably depend on magnetization value due to spontaneous volume magnetostriction. However, the separation of magnetic parts from the basic characteristics of MT is a difficult task, because the volume magnetostriction does not qualitatively change the transformational behaviour of alloy. This problem is solved for several Ni-Mn-Ga alloys by means of the quantitative theoretical analysis of experimental data obtained in the course of stress-strain tests. For each alloy, the entropy change and the transformation heat evolved in the course of MT are evaluated, first, from the results of stress-strain tests and, second, from differential scanning calorimetry data. For all alloys, a quantitative agreement between the values obtained in two different ways is observed. It is shown that the magnetic part of transformation heat exceeds the non-magnetic one for the Ni-Mn-Ga alloys undergoing MTs in ferromagnetic state, while the elevated values of transformation heat measured for the alloys undergoing MTs in paramagnetic state are caused by large MT strains.

  14. Virtual examinations of alloying elements influence on alloy structural steels mechanical properties

    OpenAIRE

    L.A. Dobrzański; R. Honysz

    2011-01-01

    Purpose: The paper introduces analysis results of selected alloying elements influence on mechanical properties of alloy structural steels for quenching and tempering.Design/methodology/approach: Investigations were performed in virtual environment with use of materials science virtual laboratory. Virtual investigations results were verified in real investigative laboratory.Findings: Materials researches performed with use of material science virtual laboratory in range of determining the mec...

  15. Effect of Plastic Deformation on Magnetic Properties of Fe-40%Ni-2%Mn Austenitic Alloy

    Institute of Scientific and Technical Information of China (English)

    Selva Büyükakkas; H Aktas; S Akturk

    2007-01-01

    The effects of plastic deformation on the magnetic properties of austenite structure in an Fe-40%Ni-2%Mn alloy is investigated by using Mssbauer spectroscopy and Differential Scanning Calorimetry (DSC) techniques The morphology of the alloy has been obtained by using Scanning Electron Microscopy (SEM). The magnetic behaviour of austenite state is ferromagnetic. After plastic deformation, a mixed magnetic structure including both paramagnetic and ferromagnetic states has been obtained at the room temperature. The volume fraction changes, the effective hyperfine fields of the ferromagnetic austenite phase and isomery shift values have also been determined by Mssbauer spectroscopy. The Curie point (TC) and the Neel temperature (TN) have been investigated by means of DSC system for non-deformed and deformed Fe-Ni-Mn alloy. The plastic deformation of the alloy reduces the TN and enhances the paramagnetic character of austenitic Fe-Ni-Mn alloy.

  16. Replacement of Cobalt base alloys hardfacing by NOREM alloy; EDF experience and development, some metallurgical considerations. Valves application (CLAMA, RAMA)

    Energy Technology Data Exchange (ETDEWEB)

    Carnus, M. [EDF DPN UTO Direction Expertise Technique, Noisy le Grand (France); Confort, X. [VELAN SAS, Lyon (France)

    2011-07-01

    Cobalt base alloys, such as Stellite 6 and 21, are used extensively in applications where superior resistance to wear and corrosion are required. However the use of Cobalt alloys hardfacing materials, especially on valves, is a major contributor to the level of radioactive contamination of nuclear facilities. NOREM alloys, an iron base and cobalt free materials, have been developed through an Electric Power Research Institute (EPRI) long running program during the eighties as an alternative of Stellite. This alloy has relatively good weldability properties, it was developed initially for repairing Stellite hardfacing (deposit over existing hardfacing alloys). This alloy has good corrosion resistance properties associated with elevated hardness (HRC 36-42). Technological properties (such as galling resistance, wear resistance) have been evaluated through different testing programs led by EPRI, AECL(Atomic Energy of Canada Limited), Valves manufacturers, EDF and others during the nineties. More recently EDF (for replacement of globe valves) has carried out testing program focused on weld deposit chemistry and mechanical properties. NOREM is a candidate for replacement of stellite hardfacing on valves. However this alloy is not so versatile as stellite alloys regarding technological properties (such as wear resistance) at elevated temperature and under high contact pressure. As a consequence some limits have to be considered for application on valves operating at elevated temperature and under high contact pressure (> 20 Mpa). Examples of application on valves, from VELAN manufacturer, for EDF PWR equipment are given. The industrial feedback from installed equipment (CLAMA, RAMA) since 2006 on EDF PWR has been good

  17. Pore structure and mechanical properties of directionally solidified porous aluminum alloys

    Directory of Open Access Journals (Sweden)

    Komissarchuk Olga

    2014-01-01

    Full Text Available Porous aluminum alloys produced by the metal-gas eutectic method or GASAR process need to be performed under a certain pressure of hydrogen, and to carry over melt to a tailor-made apparatus that ensures directional solidification. Hydrogen is driven out of the melt, and then the quasi-cylindrical pores normal to the solidification front are usually formed. In the research, the effects of processing parameters (saturation pressure, solidification pressure, temperature, and holding time on the pore structure and porosity of porous aluminum alloys were analyzed. The mechanical properties of Al-Mg alloys were studied by the compressive tests, and the advantages of the porous structure were indicated. By using the GASAR method, pure aluminum, Al-3wt.%Mg, Al-6wt.%Mg and Al-35wt.%Mg alloys with oriented pores have been successfully produced under processing conditions of varying gas pressure, and the relationship between the final pore structure and the solidification pressure, as well as the influences of Mg quantity on the pore size, porosity and mechanical properties of Al-Mg alloy were investigated. The results show that a higher pressure of solidification tends to yield smaller pores in aluminum and its alloys. In the case of Al-Mg alloys, it was proved that with the increasing of Mg amount, the mechanical properties of the alloys sharply deteriorate. However, since Al-3%Mg and Al-6wt.%Mg alloys are ductile metals, their porous samples have greater compressive strength than that of the dense samples due to the existence of pores. It gives the opportunity to use them in industry at the same conditions as dense alloys with savings in weight and material consumption.

  18. Strong and weak topology probed by surface science. Topological insulator properties of phase change alloys and heavy metal graphene

    Energy Technology Data Exchange (ETDEWEB)

    Pauly, Christian

    2015-07-01

    Christian Pauly demonstrates the strong topological properties of the technologically relevant phase change materials Sb{sub 2}Te{sub 3} and Ge{sub 2}Sb{sub 2}Te{sub 5} by using two powerful techniques for mapping the surface electronic structure: scanning tunneling spectroscopy (STS) and angle-resolved photoemission spectroscopy (ARPES). In the case of a phase change material, this opens up the possibility of switching between an insulating amorphous and a conducting topological phase on nanosecond-time scales. Moreover, the author presents first experimental results of a weak topological insulator, namely on the bismuth-based graphene-like sheet system Bi{sub 14}Rh{sub 3}I{sub 9}, revealing a topologically protected one-dimensional edge channel as its fingerprint. The edge state is as narrow as 0.8 nm, making it extremely attractive to device physics. Those strong and weak topological insulators are a new phase of quantum matter giving rise to robust boundary states which are protected from backscattering and localization.

  19. Influence of the laser modification of surface on properties and structure of magnesium alloys

    Directory of Open Access Journals (Sweden)

    L.A. Dobrzański

    2009-02-01

    Full Text Available Purpose: The aim of this work was to improve the surface layer cast magnesium cast alloys by laser surface treatment, determine the laser treatment parameters and examine structure and properties.Design/methodology/approach: The laser treatment of magnesium alloys with alloying SiC and TiC powders with the particles size below 75μm and over 6.4μm was carried out using a high power diode laser (HPDL. The resulting microstructure in the modified surface layer and was examinated using scanning electron microscopy. The X-ray qualitative and quantitative microanalysis and the analysis of a surface distribution of cast elements in the examined magnesium cast alloy was examined. The measurements of hardness and roughness of the modified surface layer was also studied.Findings: The alloyed region has a fine microstructure with hard carbide particles. Hardness of laser surface alloyed layer was dropped as compared to alloy without laser treatment. The roughness of layer surface increased after laser alloying and values are bigger for SiC alloying particles.Research limitations/implications: The investigations were conducted for cast magnesium alloys MCMgAl12Zn1 and MCMgAl9Zn1 and also TiC and SiC powders. One has used laser power in the range from 1.2 to 2.0 kW.Practical implications: The results obtained in this investigation were promising to compared other conventional processes. High Power Diode Laser can be used as an economical substitute of Nd:YAG and CO2 to improve the surface magnesium alloy by feeding the carbide particles.Originality/value: The value of this work is definition of the influence of laser treatment parameters on quality, microstructure and hardness of magnesium cast alloys surface layer.

  20. Microstructure and corrosion properties of the laser treated SUPERSTON alloy

    Directory of Open Access Journals (Sweden)

    W. Serbiński

    2006-08-01

    Full Text Available Purpose: Results of laser treatment at cryogenic conditions and its influence on microstructure, microhardnessand properties of the SUPERSTON alloy are presented in this article.Design/methodology/approach: New method of the laser remelting specimens diped in liquid nitrogen madeby the CO2 laser with 6000W laser beam power and scanning velocity 1.0 m/min was employed. Observationmicrostructure was carried out by scanning electron microscope. Hardness of cross-section of the surface layerhas been measured by the Vickers microhardness under load 0.49 N. Corrosion investigation in 3% NaCl by theAtlas 9131 equipment conected with computer PC was done.Findings: Laser remelting lets obtain fine microstructure in surface layer and increase of microhardness andcorrosion properties, compared with base material.Research limitations/implications: The future investigations connected with aplication conditions should beextend of cavitation tests in the magnetostriction stand.Practical implications: Obtained results point at possibility of the increase hardness, corrosion and cavitationresistance of the parts worked in marine conditions.Originality/value: The proposed laser treatment at cryogenic conditions could be used for surface consolidationof the copper alloys applied for ship propellers.

  1. Microstructure, electromagnetic shielding effectiveness and mechanical properties of Mg–Zn–Cu–Zr alloys

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xianhua, E-mail: xhchen@cqu.edu.cn [College of Materials Science and Engineering, Chongqing University, Chongqing 400045 (China); National Engineering Research Center for Magnesium Alloys, Chongqing University, Chongqing 400045 (China); Liu, Lizi [College of Materials Science and Engineering, Chongqing University, Chongqing 400045 (China); Pan, Fusheng [College of Materials Science and Engineering, Chongqing University, Chongqing 400045 (China); National Engineering Research Center for Magnesium Alloys, Chongqing University, Chongqing 400045 (China); Chongqing Academy of Science and Technology, Chongqing 401123 (China); Mao, Jianjun; Xu, Xiaoyang; Yan, Tao [College of Materials Science and Engineering, Chongqing University, Chongqing 400045 (China)

    2015-07-15

    Highlights: • The second phases were characterized systematically in Mg–Zn–Cu–Zr alloys. • Excellent EMI SE was successfully obtained by adding Cu. • Mechanism of EMI SE was analyzed. • Good mechanical properties could be achieved by adding low Cu content. - Abstract: The microstructure, electromagnetic interference (EMI) shielding effectiveness (SE) and mechanical properties of Mg–Zn–xCu–Zr alloys (x = 0–2.32 wt.%) were investigated in this study. The results indicated that the addition of Cu led to the formation of MgZnCu phase with a face-center cubic structure, and resulted in grain refinement. EMI SE increased significantly with increasing Cu content in extruded state. The alloy with 2.32 wt.% Cu exhibited optimal EMI shielding capacity with SE value of 84–117 dB. Meanwhile, it was found that good mechanical properties could be achieved by adding low Cu content. The extruded alloy with 0.37 wt.% Cu presented higher yield strength (276 MPa), ultimate tensile strength (346 MPa) and elongation (δ = 11.4%) compared with other extruded alloys. However, a higher Cu content would substantially deteriorate tensile properties of the alloys. Based on microstructure observation, the variation of EMI shielding capacity and mechanical properties have been discussed.

  2. The microstructure, mechanical and friction properties of protective diamond like carbon films on magnesium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Zou, Y.S., E-mail: yshzou75@gmail.com [School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing, Jiangsu, 210094 (China); Wu, Y.F.; Yang, H.; Cang, K. [School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing, Jiangsu, 210094 (China); Song, G.H. [School of Materials Science and Engineering, Shenyang University of Technology, Shenyang, Liaoning, 110178 (China); Li, Z.X.; Zhou, K. [School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing, Jiangsu, 210094 (China)

    2011-12-01

    Protective hard coatings deposited on magnesium alloys are believed to be effective for overcoming their poor wear properties. In this work, diamond-like carbon (DLC) films as hard protective films were deposited on AZ91 magnesium alloy by arc ion plating under negative pulse bias voltages ranging from 0 to -200 V. The microstructure, composition and mechanical properties of the DLC films were analyzed by scanning electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy and nanoindentation. The tribological behavior of uncoated and coated AZ91 magnesium alloy was investigated using a ball-on-disk tribotester. The results show that the negative pulse bias voltage used for film deposition has a significant effect on the sp{sup 3} carbon content and mechanical properties of the deposited DLC films. A maximum sp{sup 3} content of 33.3% was obtained at -100 V, resulting in a high hardness of 28.6 GPa and elastic modulus of 300.0 GPa. The DLC films showed very good adhesion to the AZ91 magnesium alloy with no observable cracks and delamination even during friction testing. Compared with the uncoated AZ91 magnesium alloy, the magnesium alloy coated with DLC films exhibits a low friction coefficient and a narrow, shallow wear track. The wear resistance and surface hardness of AZ91 magnesium alloy can be significantly improved by coating a layer of DLC protective film due to its high hardness and low friction coefficient.

  3. The microstructure, mechanical and friction properties of protective diamond like carbon films on magnesium alloy

    International Nuclear Information System (INIS)

    Protective hard coatings deposited on magnesium alloys are believed to be effective for overcoming their poor wear properties. In this work, diamond-like carbon (DLC) films as hard protective films were deposited on AZ91 magnesium alloy by arc ion plating under negative pulse bias voltages ranging from 0 to -200 V. The microstructure, composition and mechanical properties of the DLC films were analyzed by scanning electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy and nanoindentation. The tribological behavior of uncoated and coated AZ91 magnesium alloy was investigated using a ball-on-disk tribotester. The results show that the negative pulse bias voltage used for film deposition has a significant effect on the sp3 carbon content and mechanical properties of the deposited DLC films. A maximum sp3 content of 33.3% was obtained at -100 V, resulting in a high hardness of 28.6 GPa and elastic modulus of 300.0 GPa. The DLC films showed very good adhesion to the AZ91 magnesium alloy with no observable cracks and delamination even during friction testing. Compared with the uncoated AZ91 magnesium alloy, the magnesium alloy coated with DLC films exhibits a low friction coefficient and a narrow, shallow wear track. The wear resistance and surface hardness of AZ91 magnesium alloy can be significantly improved by coating a layer of DLC protective film due to its high hardness and low friction coefficient.

  4. The microstructure, mechanical and friction properties of protective diamond like carbon films on magnesium alloy

    Science.gov (United States)

    Zou, Y. S.; Wu, Y. F.; Yang, H.; Cang, K.; Song, G. H.; Li, Z. X.; Zhou, K.

    2011-12-01

    Protective hard coatings deposited on magnesium alloys are believed to be effective for overcoming their poor wear properties. In this work, diamond-like carbon (DLC) films as hard protective films were deposited on AZ91 magnesium alloy by arc ion plating under negative pulse bias voltages ranging from 0 to -200 V. The microstructure, composition and mechanical properties of the DLC films were analyzed by scanning electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy and nanoindentation. The tribological behavior of uncoated and coated AZ91 magnesium alloy was investigated using a ball-on-disk tribotester. The results show that the negative pulse bias voltage used for film deposition has a significant effect on the sp3 carbon content and mechanical properties of the deposited DLC films. A maximum sp3 content of 33.3% was obtained at -100 V, resulting in a high hardness of 28.6 GPa and elastic modulus of 300.0 GPa. The DLC films showed very good adhesion to the AZ91 magnesium alloy with no observable cracks and delamination even during friction testing. Compared with the uncoated AZ91 magnesium alloy, the magnesium alloy coated with DLC films exhibits a low friction coefficient and a narrow, shallow wear track. The wear resistance and surface hardness of AZ91 magnesium alloy can be significantly improved by coating a layer of DLC protective film due to its high hardness and low friction coefficient.

  5. Characterization and property evaluation of U-15 wt%Pu alloy for fast reactor

    Science.gov (United States)

    Kaity, Santu; Banerjee, Joydipta; Ravi, K.; Keswani, R.; Kutty, T. R. G.; Kumar, Arun; Prasad, G. J.

    2013-02-01

    The characterization and high temperature behaviour of U-15 wt%Pu alloy has been investigated in this study for the first time. U-15 wt%Pu alloy sample for this study was prepared by following melting and casting route. Microstructural characterization of the alloy was carried out by XRD and optical microscopy. The thermophysical properties like phase transition temperatures, coefficient of thermal expansion and hot hardness of the above alloy were determined. Eutectic temperature between T91 and U-15 wt%Pu was established. Apart from that, the fuel-cladding chemical compatibility of U-15 wt%Pu alloy with T91 grade steel was studied by diffusion couple experiment.

  6. Melting, Processing, and Properties of Disordered Fe-Al and Fe-Al-C Based Alloys

    Science.gov (United States)

    Satya Prasad, V. V.; Khaple, Shivkumar; Baligidad, R. G.

    2014-09-01

    This article presents a part of the research work conducted in our laboratory to develop lightweight steels based on Fe-Al alloys containing 7 wt.% and 9 wt.% aluminum for construction of advanced lightweight ground transportation systems, such as automotive vehicles and heavy-haul truck, and for civil engineering construction, such as bridges, tunnels, and buildings. The melting and casting of sound, porosity-free ingots of Fe-Al-based alloys was accomplished by a newly developed cost-effective technique. The technique consists of using a special flux cover and proprietary charging schedule during air induction melting. These alloys were also produced using a vacuum induction melting (VIM) process for comparison purposes. The effect of aluminum (7 wt.% and 9 wt.%) on melting, processing, and properties of disordered solid solution Fe-Al alloys has been studied in detail. Fe-7 wt.% Al alloy could be produced using air induction melting with a flux cover with the properties comparable to the alloy produced through the VIM route. This material could be further processed through hot and cold working to produce sheets and thin foils. The cold-rolled and annealed sheet exhibited excellent room-temperature ductility. The role of carbon in Fe-7 wt.% Al alloys has also been examined. The results indicate that Fe-Al and Fe-Al-C alloys containing about 7 wt.% Al are potential lightweight steels.

  7. Effect of heat treatment on the microstructures and damping properties of biomedical Mg-Zr alloy

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, Ming-Hung [Department of Mechanical Engineering and Graduate Institute of Mechanical and Precision Engineering, National Kaoshiung University of Applied Sciences, Kaoshiung 807, Taiwan (China); Department of Dentistry, Chang Yin dental clinic, No.46-1, Yangming St., Banqiao City, Taipei County 220, Taiwan (China); Research Center for Biomedical Devices, Taipei Medical University, Taipei 110, Taiwan (China); Chen, May-Show [Research Center for Biomedical Devices, Taipei Medical University, Taipei 110, Taiwan (China); School of Oral Hygiene, College of Oral Medicine, Taipei Medical University, Taipei 110, Taiwan (China); Department of Dentistry, Taipei Medical University Hospital, Taipei 110, Taiwan (China); Lin, Ling-Hung [Department of Dentistry, Taipei Medical University Hospital, Taipei 110, Taiwan (China); School of Dentistry, College of Oral Medicine, Taipei Medical University, Taipei 110, Taiwan (China); Lin, Ming-Hong [Department of Mechanical Engineering and Graduate Institute of Mechanical and Precision Engineering, National Kaoshiung University of Applied Sciences, Kaoshiung 807, Taiwan (China); Wu, Ching-Zong, E-mail: chinaowu@tmu.edu.tw [Department of Dentistry, Taipei Medical University Hospital, Taipei 110, Taiwan (China); School of Dentistry, College of Oral Medicine, Taipei Medical University, Taipei 110, Taiwan (China); Ou, Keng-Liang, E-mail: klou@tmu.edu.tw [Research Center for Biomedical Devices, Taipei Medical University, Taipei 110, Taiwan (China); Graduated Institute of Biomedical Materials and Engineering, Taipei Medical University, Taipei 110, Taiwan (China); Research Center for Biomedical Implants and Microsurgery Devices, Taipei Medical University, Taipei 110, Taiwan (China); Yu, Chih-Hua [Research Center for Biomedical Devices, Taipei Medical University, Taipei 110, Taiwan (China); Research Center for Biomedical Implants and Microsurgery Devices, Taipei Medical University, Taipei 110, Taiwan (China)

    2011-01-21

    Research highlights: > When the as-quenched Mg-1Zr alloy was aged at temperatures ranging from 200 deg. C to 500 deg. C, a microstructural transformation sequence was found to be {alpha}-Mg {yields} ({alpha}-Mg + twin{sub dense}) {yields} ({alpha}-Mg + twin{sub loose}) {yields} ({alpha}-Mg + {alpha}-Zr). > As the as-quenched Mg-1Zr alloy was subjected to aging treatment at 300 deg. C for 16 h, it exhibited the maximum damping properties. > The twin structure plays a crucial role in increasing the damping capacity of the Mg-1Zr alloy. - Abstract: In this study, we elucidated the effect of heat treatment on the microstructures and damping properties of the biomedical Mg-1 wt% Zr (K1) alloy by optical microscopy, transmission electron microscopy, energy-dispersive X-ray spectrometry, and experimental model analysis. The following microstructural transformation occurred when the as-quenched (AQ, i.e., solution heat treated and quenched) K1 alloy was subjected to aging treatment in the temperature range 200-500 deg. C: {alpha}-Mg {yields} ({alpha}-Mg + twin{sub dense}) {yields} ({alpha}-Mg + twin{sub loose}) {yields} ({alpha}-Mg + {alpha}-Zr). This microstructural transformation was accompanied by variations in the damping capacity. The damping properties of the AQ K1 alloy subjected to aging treatment at 300 deg. C for 16 h were the best among those of the alloys investigated in the present study. The presence of twin structures in the alloy matrix was thought to play a crucial role in increasing the damping capacity of the K1 alloy. Hence, we state that a combination of solution treatment and aging is an effective means of improving the damping capacity of biomedical K1 alloys.

  8. Effect of heat treatment on the microstructures and damping properties of biomedical Mg-Zr alloy

    International Nuclear Information System (INIS)

    Research highlights: → When the as-quenched Mg-1Zr alloy was aged at temperatures ranging from 200 deg. C to 500 deg. C, a microstructural transformation sequence was found to be α-Mg → (α-Mg + twindense) → (α-Mg + twinloose) → (α-Mg + α-Zr). → As the as-quenched Mg-1Zr alloy was subjected to aging treatment at 300 deg. C for 16 h, it exhibited the maximum damping properties. → The twin structure plays a crucial role in increasing the damping capacity of the Mg-1Zr alloy. - Abstract: In this study, we elucidated the effect of heat treatment on the microstructures and damping properties of the biomedical Mg-1 wt% Zr (K1) alloy by optical microscopy, transmission electron microscopy, energy-dispersive X-ray spectrometry, and experimental model analysis. The following microstructural transformation occurred when the as-quenched (AQ, i.e., solution heat treated and quenched) K1 alloy was subjected to aging treatment in the temperature range 200-500 deg. C: α-Mg → (α-Mg + twindense) → (α-Mg + twinloose) → (α-Mg + α-Zr). This microstructural transformation was accompanied by variations in the damping capacity. The damping properties of the AQ K1 alloy subjected to aging treatment at 300 deg. C for 16 h were the best among those of the alloys investigated in the present study. The presence of twin structures in the alloy matrix was thought to play a crucial role in increasing the damping capacity of the K1 alloy. Hence, we state that a combination of solution treatment and aging is an effective means of improving the damping capacity of biomedical K1 alloys.

  9. Effect of Sr on forming properties of Al-Mg-Si based alloy sheets

    Institute of Scientific and Technical Information of China (English)

    LU Guang-xi; CHEN Hai-jun; GUAN Shao-kang

    2006-01-01

    The effects of Sr element on the forming properties of the Al-Mg-Si based alloy sheets were studied by tensile test,metallograph, DSC, XRD, SEM and TEM. The results show that the tensile strength of aluminum alloy sheet added 0.033%(mass fraction)Sr increases comparing with that of free Sr. Simultaneously, the forming properties of sheets evidently increase, the elongation hardenability (n) and plastic strain ratio (r) and Erichsen number increase 27.8%, 11.1%, 10.8% and 12%, respectively,and the forming limit diagram increases evidently, too. The analysis shows that Sr is surface active element, which can refine grains of alloys, promote precipitation, reduce activation energy ofβ" phase, and lead the formation of α-(Al8Fe2Si) phase instead of β-(Al5FeSi) phase. As a result, the forming properties of the alloy sheet increase.

  10. Corrosion resistance and magnetostrictive properties of (Tb0.3Dy0.7)Fe2 alloy modified by nitrogen ion implantation

    Institute of Scientific and Technical Information of China (English)

    杨红川; 张世荣; 于敦波; 李扩社; 胡权霞; 杨远飞; 张坤; 李红卫

    2015-01-01

    The corrosion resistance and magnetostriction of (Tb0.3Dy0.7)Fe2 alloy were investigated for different nitrogen doses of 5×1015, 5×1016, 5×1017, 1×1018 ions/cm2 and average ion energy of 140 kV. The phase and elements concentration in the implanted layer were examined by X-ray diffraction and auger electron spectroscopy, respectively.The aqueous corrosion studies were carried out in 3.5% NaCl solutions. It was found that corrosion resistance had improved substantially with respect to the untreated substrates.The corrosion resistance was maximum at a dose of 5×1017 ions/cm2, and saturation in corrosion improvement was noticed at a higher dose, 10×1017 ions/cm2.In contrast, the results of magnetostriction tests before and after ion implantation showed that the influence of ni-trogen ion implantation on the magnetostrictive properties turned out to be small. Finally, a model was applied to interpret the influ-ence of nitrogen implantation on the magnetostriction in the light of the information provided by the experimental results in this study.

  11. Interlaboratory Study for Nickel Alloy 625 Made by Laser Powder Bed Fusion to Quantify Mechanical Property Variability

    Science.gov (United States)

    Brown, Christopher U.; Jacob, Gregor; Stoudt, Mark; Moylan, Shawn; Slotwinski, John; Donmez, Alkan

    2016-08-01

    Six different organizations participated in this interlaboratory study to quantify the variability in the tensile properties of Inconel 625 specimens manufactured using laser powder bed fusion-additive manufacturing machines. The tensile specimens were heat treated and tensile tests were conducted until failure. The properties measured were yield strength, ultimate tensile strength, elastic modulus, and elongation. Statistical analysis revealed that between-participant variability for yield strength, ultimate tensile strength, and elastic modulus values were significantly higher (up to four times) than typical within-participant variations. Only between-participant and within-participant variability were both similar for elongation. A scanning electron microscope was used to examine one tensile specimen for fractography. The fracture surface does not have many secondary cracks or other features that would reduce the mechanical properties. In fact, the features largely consist of microvoid coalescence and are entirely consistent with ductile failure.

  12. Interlaboratory Study for Nickel Alloy 625 Made by Laser Powder Bed Fusion to Quantify Mechanical Property Variability

    Science.gov (United States)

    Brown, Christopher U.; Jacob, Gregor; Stoudt, Mark; Moylan, Shawn; Slotwinski, John; Donmez, Alkan

    2016-06-01

    Six different organizations participated in this interlaboratory study to quantify the variability in the tensile properties of Inconel 625 specimens manufactured using laser powder bed fusion-additive manufacturing machines. The tensile specimens were heat treated and tensile tests were conducted until failure. The properties measured were yield strength, ultimate tensile strength, elastic modulus, and elongation. Statistical analysis revealed that between-participant variability for yield strength, ultimate tensile strength, and elastic modulus values were significantly higher (up to four times) than typical within-participant variations. Only between-participant and within-participant variability were both similar for elongation. A scanning electron microscope was used to examine one tensile specimen for fractography. The fracture surface does not have many secondary cracks or other features that would reduce the mechanical properties. In fact, the features largely consist of microvoid coalescence and are entirely consistent with ductile failure.

  13. Microstructure and mechanical properties of ARB processed Mg-3%Gd alloy

    DEFF Research Database (Denmark)

    Wu, J.Q.; Huang, S.; Wang, Y.H.;

    2015-01-01

    by accumulative roll-bonding (ARB) at 400℃ to 4 cycles followed by annealing at various temperatures. The microstructures after annealing were characterized by the electron backscatter diffraction technique and the mechanical properties were measured by a tensile test. It was found that the alloy has a good...... properties were related to the fine-sized heterogeneous microstructures and weakened texture....

  14. 新型耐磨锡青铜合金包套挤压工艺及组织性能%Microstructure and properties of wear-resisting Cu-Sn-Pb-Ni alloy prepared by canning extrusion process

    Institute of Scientific and Technical Information of China (English)

    赵培峰; 周延军; 宋克兴; 张彦敏

    2012-01-01

    Directing to the difficulties in the densification of Cu-Sn-Pb-Ni alloy containing 8%~12% tin by conventional plastic forming,the plastic deformation of Cu-Sn-Pb-Ni alloy was carried out by the canning extrusion process.The microstructure and properties of as-cast alloy and as-extruded alloy were analyzed.The as-extruded alloy with the density of 8.98g/cm3 and strength of 345MPa was obtained.The results reveal that the properties of the Cu-Sn-Pb-Ni alloy can be improved via the canning extrusion process.%针对锡含量为8%~12%的锡青铜合金脆性大,难以通过塑性变形实现较高致密度的问题,采用包套挤压工艺制备新型耐磨Cu-Sn-Pb-Ni合金,分析其铸态及包套挤压态的微观组织及性能.包套挤压的密度和硬度分别达到8.98g/cm3和HB135.7;挤压后合金抗拉强度和伸长率分别为345.366MPa和11.4%.结果表明,合金在外加包套作用下塑性有所提高.

  15. Microstructure modification by La2O3 and its effect on wear resistance properties of as-cast ZL107 alloy

    Institute of Scientific and Technical Information of China (English)

    WAN Diqing

    2010-01-01

    Modification of ZL107 aluminum alloy has been successfully achieved by using La2O3. The different casting parameters, including casting temperature as well as holding time and modifier content, were carried out to investigate the modification effects. The results show that the best modifier content is 1.0 wt.%, and the casting temperature has little effect. In addition, the wear behavior of modified and unmodified ZL107 has been compared. The wear resistance of as-cast ZL107 aluminum alloy can be significantly improved after modification.

  16. Mechanical properties and corrosion resistance of low rigidity quaternary titanium alloy for biomedical applications

    Institute of Scientific and Technical Information of China (English)

    Han-Cheol CHOE; Viswanathan S. SAJI; Yeong-Mu KO

    2009-01-01

    Electrochemical corrosion of Ti-35Nb-5Ta-7Zr alloy fabricated by arc melting and heat treatment process was studied in 0.9% NaCl at (37±1) ℃. Phase and microstructure of the fabricated alloy were investigated using X-ray diffractometer and scanning electron microscope. Mechanical properties such as yield strength and elastic modulus of the alloy were determined by tensile test. Potentiodynamic polarization technique and impedance spectroscopy were employed to study the corrosion behavior. The results of the study were compared with those obtained for Ti-6Al-4V commercial alloy. The result of the study supports feasibility of Ti-35Nb-5Ta-7Zr alloy for implant applications.

  17. Nanomechanical properties of surface-modified titanium alloys for biomedical applications.

    Science.gov (United States)

    Cáceres, D; Munuera, C; Ocal, C; Jiménez, J A; Gutiérrez, A; López, M F

    2008-09-01

    The mechanical properties of the oxide layers developed at elevated temperature on three vanadium-free titanium alloys of interest for biomedical applications were investigated by means of the nanoindentation technique. The as-received alloys (Ti-13Nb-13Zr, Ti-15Zr-4Nb and Ti-7Nb-6Al) and their oxide scales formed by reaction with air at 750 degrees C for several oxidation times were analysed comparatively. In particular, the hardness and the Young's modulus exhibit larger values for the thermally oxidized alloys than for the untreated specimens. However, the Ti-7Nb-6Al alloy shows a different tendency to that of the TiNbZr alloys, which seems to be related to a different oxide layer growth as a function of the oxidation time.

  18. Microstructures and properties of silver-based contact material fabricated by hot extrusion of internal oxidized Ag–Sn–Sb alloy powders

    International Nuclear Information System (INIS)

    Highlights: ► A new Ag/SnO2 contact material was prepared by powder hot extrusion method. ► The distribution of oxide particles dependent on extrusion ratio was discussed. ► Reinforced particles of SnO2 and Ag1.7Sb2O5.77 were clearly characterized. ► Effects of extrusion ratio and annealing on composite properties were discussed. - Abstract: In the present study, powder internal oxidation and hot extrusion were used to prepare silver metal oxide (Ag-MeO) contact materials. Water atomized Ag–5.08 wt.%Sn–3.15 wt.%Sb alloy powders were internal oxidized and hot extruded with extrusion ratios of 49:4 and 49:1. The microstructures of composite powders and final products were studied by OM, SEM and TEM in details. The distribution of oxide particles in silver matrix are highly depended upon extrusion ratios. The oxide particles refined by the fracture of oxide clusters and distributed more uniform in the 49:1 extrusion. SnO2 and Ag1.7Sb2O5.77 are two kinds of reinforced particles identified. The influence of extrusion ratio and following anneal treatment on the properties, including of density, Vickers hardness and electric conductivity, were discussed. The best performance exhibited on the annealed sample of 49:1 extrusion, with density, Vickers hardness and electrical conductivity of 9.83 g/cm3, 91.6 HV and 71%IACS, respectively.

  19. Mechanical properties, in vitro corrosion and biocompatibility of newly developed biodegradable Mg-Zr-Sr-Ho alloys for biomedical applications

    Science.gov (United States)

    Ding, Yunfei; Lin, Jixing; Wen, Cuie; Zhang, Dongmei; Li, Yuncang

    2016-08-01

    Our previous studies have demonstrated that Mg-Zr-Sr alloys can be anticipated as excellent biodegradable implant materials for load-bearing applications. In general, rare earth elements (REEs) are widely used in magnesium (Mg) alloys with the aim of enhancing the mechanical properties of Mg-based alloys. In this study, the REE holmium (Ho) was added to an Mg-1Zr-2Sr alloy at different concentrations of Mg1Zr2SrxHo alloys (x = 0, 1, 3, 5 wt. %) and the microstructure, mechanical properties, degradation behaviour and biocompatibility of the alloys were systematically investigated. The results indicate that the addition of Ho to Mg1Zr2Sr led to the formation of the intermetallic phases MgHo3, Mg2Ho and Mg17Sr2 which resulted in enhanced mechanical strength and decreased degradation rates of the Mg-Zr-Sr-Ho alloys. Furthermore, Ho addition (≤5 wt. %) to Mg-Zr-Sr alloys led to enhancement of cell adhesion and proliferation of osteoblast cells on the Mg-Zr-Sr-Ho alloys. The in vitro biodegradation and the biocompatibility of the Mg-Zr-Sr-Ho alloys were both influenced by the Ho concentration in the Mg alloys; Mg1Zr2Sr3Ho exhibited lower degradation rates than Mg1Zr2Sr and displayed the best biocompatibility compared with the other alloys.

  20. Mechanical properties, in vitro corrosion and biocompatibility of newly developed biodegradable Mg-Zr-Sr-Ho alloys for biomedical applications.

    Science.gov (United States)

    Ding, Yunfei; Lin, Jixing; Wen, Cuie; Zhang, Dongmei; Li, Yuncang

    2016-01-01

    Our previous studies have demonstrated that Mg-Zr-Sr alloys can be anticipated as excellent biodegradable implant materials for load-bearing applications. In general, rare earth elements (REEs) are widely used in magnesium (Mg) alloys with the aim of enhancing the mechanical properties of Mg-based alloys. In this study, the REE holmium (Ho) was added to an Mg-1Zr-2Sr alloy at different concentrations of Mg1Zr2SrxHo alloys (x = 0, 1, 3, 5 wt. %) and the microstructure, mechanical properties, degradation behaviour and biocompatibility of the alloys were systematically investigated. The results indicate that the addition of Ho to Mg1Zr2Sr led to the formation of the intermetallic phases MgHo3, Mg2Ho and Mg17Sr2 which resulted in enhanced mechanical strength and decreased degradation rates of the Mg-Zr-Sr-Ho alloys. Furthermore, Ho addition (≤5 wt. %) to Mg-Zr-Sr alloys led to enhancement of cell adhesion and proliferation of osteoblast cells on the Mg-Zr-Sr-Ho alloys. The in vitro biodegradation and the biocompatibility of the Mg-Zr-Sr-Ho alloys were both influenced by the Ho concentration in the Mg alloys; Mg1Zr2Sr3Ho exhibited lower degradation rates than Mg1Zr2Sr and displayed the best biocompatibility compared with the other alloys. PMID:27553403

  1. Microstructure and Mechanical Properties of WE43 Alloy Produced Via Additive Friction Stir Technology

    OpenAIRE

    Calvert, Jacob Rollie

    2015-01-01

    In an effort to save weight, transportation and aerospace industries have increasing investigated magnesium alloys because of their high strength-to-weight ratio. Further efforts to save on material use and machining time have focused on the use of additive manufacturing. However, anisotropic properties can be caused by both the HCP structure of magnesium alloys as well as by layered effects left by typical additive manufacturing processes. Additive Friction Stir (AFS) is a relatively new add...

  2. Fabrication and electromagnetic properties of bio-based helical soft-core particles by way of Ni-Fe alloy electroplating

    International Nuclear Information System (INIS)

    Ni-Fe alloy electroplating was used as a bio-limited forming process to fabricate bio-based helical soft-core ferromagnetic particles, and a low frequency vibration device was applied to the cathode to avoid microorganism (Spirulina platens) cells adhesion to the copper net during the course of plating. The morphologies and ingredients of the coated Spirulina cells were characterized using scanning electron microscopy and energy dispersive spectrometer. The complex permittivity and permeability of the samples containing the coated Spirulina cells before and after heat treatment were measured and investigated by a vector network analyzer. The results show that the Spirulina cells after plating keep their initial helical shape, and applying low frequency vibration to the copper net cathode in the plating process can effectively prevent agglomeration and intertwinement of the Spirulina cells. The microwave absorbing and electromagnetic properties of the samples containing the coated Spirulina cells particles with heat treatment are superior to those samples containing the coated Spirulina cells particles without heat treatment. - Highlights: → We used the microorganism cells as forming template to fabricate the bio-based helical soft-core ferromagnetic particles. → Microorganism selected as forming templates was Spirulina platens, which are of natural helical shape and have high aspect ratio. → Coated Spirulina cells were a kind lightweight ferromagnetic particle.

  3. Effect of Surface States on Joining Mechanisms and Mechanical Properties of Aluminum Alloy (A5052 and Polyethylene Terephthalate (PET by Dissimilar Friction Spot Welding

    Directory of Open Access Journals (Sweden)

    Farazila Yusof

    2016-04-01

    Full Text Available In this research, polyethylene terephthalate (PET, as a high-density thermoplastic sheet, and Aluminum A5052, as a metal with seven distinct surface roughnesses, were joined by friction spot welding (FSW. The effect of A5052’s various surface states on the welding joining mechanism and mechanical properties were investigated. Friction spot welding was successfully applied for the dissimilar joining of PET thermoplastics and aluminum alloy A5052. During FSW, the PET near the joining interface softened, partially melted and adhered to the A5052 joining surface. The melted PET evaporated to form bubbles near the joining interface and cooled, forming hollows. The bubbles have two opposite effects: its presence at the joining interface prevent PET from contacting with A5052, while bubbles or hollows are crack origins that induce crack paths which degrade the joining strength. On the other hand, the bubbles’ flow pushed the softened PET into irregularities on the roughened surface to form mechanical interlocking, which significantly improved the strength. The tensile-shear failure load for an as-received surface (0.31 μ m Ra specimen was about 0.4–0.8 kN while that for the treated surface (>0.31 μ m Ra specimen was about 4.8–5.2 kN.

  4. Structure–mechanical property relationship in a high strength low carbon alloy steel processed by two-step intercritical annealing and intercritical tempering

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, W.H. [School of Materials Science and Engineering, University of Science and Technology, Beijing (China); Laboratory for Excellence in Advanced Steel Research, Center for Structural and Functional Materials, Institute for Material Research and Innovation, University of Louisiana at Lafayette, P.O. Box 44130, Lafayette, LA 70503 (United States); Wang, X.L. [School of Materials Science and Engineering, University of Science and Technology, Beijing (China); Venkatsurya, P.K.C. [Laboratory for Excellence in Advanced Steel Research, Center for Structural and Functional Materials, Institute for Material Research and Innovation, University of Louisiana at Lafayette, P.O. Box 44130, Lafayette, LA 70503 (United States); Guo, H. [School of Materials Science and Engineering, University of Science and Technology, Beijing (China); Shang, C.J., E-mail: cjshang@ustb.edu.cn [School of Materials Science and Engineering, University of Science and Technology, Beijing (China); Misra, R.D.K. [Laboratory for Excellence in Advanced Steel Research, Center for Structural and Functional Materials, Institute for Material Research and Innovation, University of Louisiana at Lafayette, P.O. Box 44130, Lafayette, LA 70503 (United States)

    2014-06-01

    The influence of annealing and tempering temperature on the microstructure and mechanical properties was investigated in a low carbon alloy steel that was processed by a two-step intercritical annealing and intercritical tempering heat treatment. In general, the microstructure of the processed steel comprises intercritical lath-like ferrite, bainitic/martensitic lath and acicular-type retained austenite. The lower intercritical annealing temperature resulted in lower fraction of intercritical ferrite with finer grain size and consequently higher strength. On the other hand, the intercritical tempering temperature significantly influenced retained austenite content and precipitation. High fraction of retained austenite was obtained at a temperature slightly above Ac{sub 1} temperature and retained austenite content decreased with increase in tempering temperature. This behavior is attributed to the competition between the enrichment of Mn and Ni and the fraction of reversed austenite. Fine niobium carbide precipitates of size ∼2–6 nm and copper precipitates of size range ∼10–30 nm were obtained. The optimal intercritical annealing and tempering temperatures to obtain the product of tensile strength and elongation % of ∼30 GPa% were 780 °C and 660 °C, respectively and the volume fraction of retained austenite was ∼29%.

  5. Fabrication and electromagnetic properties of bio-based helical soft-core particles by way of Ni-Fe alloy electroplating

    Energy Technology Data Exchange (ETDEWEB)

    Lan Mingming, E-mail: lan_mingming@163.com [Bionic and Micro/Nano/Bio Manufacturing Technology Research Center, School of Mechanical Engineering and Automation, Beihang University, Beijing 100191 (China); Zhang Deyuan; Cai Jun; Zhang Wenqiang; Yuan Liming [Bionic and Micro/Nano/Bio Manufacturing Technology Research Center, School of Mechanical Engineering and Automation, Beihang University, Beijing 100191 (China)

    2011-12-15

    Ni-Fe alloy electroplating was used as a bio-limited forming process to fabricate bio-based helical soft-core ferromagnetic particles, and a low frequency vibration device was applied to the cathode to avoid microorganism (Spirulina platens) cells adhesion to the copper net during the course of plating. The morphologies and ingredients of the coated Spirulina cells were characterized using scanning electron microscopy and energy dispersive spectrometer. The complex permittivity and permeability of the samples containing the coated Spirulina cells before and after heat treatment were measured and investigated by a vector network analyzer. The results show that the Spirulina cells after plating keep their initial helical shape, and applying low frequency vibration to the copper net cathode in the plating process can effectively prevent agglomeration and intertwinement of the Spirulina cells. The microwave absorbing and electromagnetic properties of the samples containing the coated Spirulina cells particles with heat treatment are superior to those samples containing the coated Spirulina cells particles without heat treatment. - Highlights: > We used the microorganism cells as forming template to fabricate the bio-based helical soft-core ferromagnetic particles. > Microorganism selected as forming templates was Spirulina platens, which are of natural helical shape and have high aspect ratio. > Coated Spirulina cells were a kind lightweight ferromagnetic particle.

  6. The properties of silicon alloyed ferritic ductile irons

    Directory of Open Access Journals (Sweden)

    Z. Glavas

    2016-07-01

    Full Text Available In this paper the influence of silicon content of 3,1 to 5,4 wt. % on the tensile properties, hardness and impact energy of ferritic ductile iron was analysed. It was found that silicon strengthens the ferrite, resulting in an increase in yield strength and tensile strength with increasing silicon content up to 4,22 wt. %. Elongation and impact energy decreases and the hardness increases with increasing silicon content. Since ferritic ductile irons alloyed and strengthened by silicon have a higher Rp0,2/Rm ratio and a higher elongation than conventional ferritic, ferritic/pearlitic and pearlitic ductile irons at the same level of tensile strength, we can expect an increased demand for these materials in applications where high resistance to impact load and low temperature impact properties are not required.

  7. Effect of Rare Earth Metals on Structure and Properties of Electroless Co-B Alloy Coating

    Institute of Scientific and Technical Information of China (English)

    宣天鹏; 张雷; 黄秋华

    2002-01-01

    The effect of rare earth metals cerium, lanthanum and yttrium on chemical composition, structure and properties of electroless Co-B alloy coating was studied. By plasma transmitting spectrograph, electron energy spectrometer, X-ray diffractometter, micro-hardometer and vibratory sample magnetometer the chemical constitution, structure and properties of the alloy coatings were analyzed and inspected. The results show that with a tiny quantity of rare earth metal added into Co-B alloy coating, the content of boron is decreased in the alloy coatings, and the kinds of rare earth metal have enormous effect on the structure and properties of electroless Co-B alloy coating. At the same time electroless Co-B alloy with amorphous structure is transformed to electroless Co-B-RE alloy with microcrystalline or crystalline structure. In this way microhardness of the coatings is increased remarkably. Cerium and lanthanum would also increase the saturated magnetic intensity and decrease coercitive force of the coating. So soft magnetization of the coatings would be improved.

  8. Microstructure and Mechanical Properties of Solution Heat-Treated Alloy 617 ODS Alloy

    International Nuclear Information System (INIS)

    Alloy 617 is a solution hardened Ni-based Superalloy containing Cr, Co, Mo, and Fe, and is among the best candidate materials for the key components of VHTR (Very High Temperature Reactor) system. As an alternative, Oxide Dispersion Strengthened (ODS) Ni-based superalloys, are known to possess superior high temperature mechanical properties and long-term high temperature microstructural stability due to the nano sized oxide dispersoids, which effectively hinder the dislocation motion at high temperature. This study is focused on the fabrication and characterization of nanosized oxide dispersion strengthened alloy 617. The influences of alloy composition and processing variables such as the content of Y2O3, hot extrusion ratio, and hydrogen reduction on the microstructure and mechanical properties were studied. From the analyses of microstructure of solution heat treated Alloy 617 ODS alloy specimens, a proper solid solution heat treatment temperature to reduce carbides is 1250 .deg. C. The major phases present in the alloy 617 ODS were found to be M23C6 and Al-O

  9. Enhancement of wear and corrosion resistance of beta titanium alloy by laser gas alloying with nitrogen

    DEFF Research Database (Denmark)

    Chan, Chi-Wai; Lee, Seunghwan; Smith, Graham;

    2016-01-01

    be resolved before commercialising in the orthopaedic market. In this work, a newly developed laser surface treatment technique was employed to improve the surface properties of Ti-35.3Nb-7.3Zr-5.7Ta alloy. The surface structure and composition of the laser-treated TNZT surface were examined by grazing...

  10. Relationship of microstructure and tensile properties for neutron-irradiated vanadium alloys

    International Nuclear Information System (INIS)

    The microstructures in V-15Cr-5Ti, V-10Cr-5RTi, V-3Ti-1Si, V-15Ti-7.5Cr, and V-20Ti alloys were examined by transmission electron microscopy after neutron irradiation at 600 degree C to 21--84 atom displacements per atom in the Materials Open Test Assembly of the Fast Flux Test Facility. The microstructures in these irradiated alloys were analyzed to determine the radiation-produced dislocation density, precipitate number density and size, and void number density and size. The results of these analyses were used to compute increases in yield stress and swelling of the irradiated alloys. The computed increase in yield stress was compared with the increase in yield stress determined from tensile tests on these irradiated alloys. This comparison made it possible to evaluate the influence of alloy composition on the evolution of radiation-damaged microstructures and the resulting tensile properties. 11 refs

  11. Thermal stability and mechanical properties of Gd-Co-Al bulk glass alloys

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The glass forming ability of Gd-Co-Al ternary alloy systems with a composition ranging from 50% to 70% (molar fraction)for Gd and from 5% to 40% (molar fraction) for Al were investigated by copper mold casting and Gd60Co25Al15 bulk glass alloy cylinders with the maximum diameter of 5 mm were obtained. The reduced glass transformation temperature (Tg/Tm) and the distance of supercooling region △Tx are 0.616 and 45 K, respectively for this Gd-Co-Al alloy. The compressive fracture strength (σf) and elastic modulus (E) of Gd-Co-Al glassy alloys are 1 170-1 380 MPa and 59-70 GPa, respectively. The Gd-Al-Co bulk glassy alloys with high glass forming ability and good mechanical properties are promising for the future development as a new type function materials.

  12. Structural and optical properties of single-phase ZnO1−xSx alloy films epitaxially grown by pulsed laser deposition

    International Nuclear Information System (INIS)

    Highlights: • We grew epitaxial ZnO1-xSx (x ≤ 0.18) films by PLD with a ZnS ceramic target and O2. • Lattice parameters (c, a) and Eg of single-phase ZnO1−xSx alloys were determined. • C and a expand from 5.204 to 5.366 Å and 3.255 to 3.329 Å with increasing S content. • The optical bandgap shrinks from 3.27 to 2.92 eV with a bowing parameter of 2.91 eV. • In-plane perfectly matched ZnOS/MgZnO heterostructures with max. barrier are proposed. -- Abstract: We report on a detailed investigation of the structural and optical properties of single crystalline ZnO1−xSx thin films, placing emphasis on the elucidation of the correlation of the band gap and lattice parameters, particularly the lattice constant a, with the S content in the alloy films. High-quality ZnO1−xSx thin films with different S concentrations Xs (0 ⩽ Xs ⩽ 0.18) were grown epitaxially on c-plane sapphire substrates by pulsed laser deposition using a ZnS ceramic target with varying O2 partial pressures. X-ray diffraction studies revealed that all grown ZnO1−xSx thin films have a single-phase wurtzite structure. With increasing Xs value from 0 to 0.18, both lattice constants c and a expand monotonically from 5.204 to 5.366 Å and from 3.255 to 3.329 Å, respectively, while the optical band gap shrinks from 3.27 to 2.92 eV with a bowing parameter of 2.91 eV. Based on these information, ZnOS/MgZnO heterostructures that have a perfect in-plane lattice match and a maximum barrier height can be proposed, which might eventually lead to new optoelectronic devices with superior performance

  13. Effects of cryogenic treatment on mechanical properties of extruded Mg-Gd-Y-Zr(Mn) alloys

    Institute of Scientific and Technical Information of China (English)

    XIONG Chuang-xian; ZHANG Xin-ming; DENG Yun-lai; XIAO Yang; DENG Zhen-zhen; CHEN Bu-xiang

    2007-01-01

    The influence of cryogenic treatment on the mechanical properties of the extruded Mg-Gd-Y-Zr(Mn) alloys was investigated by the tensile tests, scanning electron microscopy(SEM), transmission electron microscopy(TEM), and energy dispersive X-ray spectroscopy (EDS). The results show that the mechanical properties of both alloys are improved greatly during the in situ tensile test by soaking the samples in liquid nitrogen for 10 min. The ultimate tensile strength, yield tensile strength and elongation of cryogenic treated magnesium alloy added with zirconium or manganese are largely elevated. And remarkable microstructure change is observed in both alloys by cryogenic treatment. There are a large number of twins, rod-like, tree-like and chrysanthemum-like precipitated phases in the microstructures and the fracture surfaces exhibit the characteristics of ductile rupture when they are observed at room temperature.

  14. Magnetic and mechanical properties in FeXSiB (X = Cu, Zr, Co) amorphous alloys

    OpenAIRE

    P. Kwapuliński; Rasek, J.; Z. Stokłosa; G. Badura; B. Kostrubiec; Haneczok, G.

    2008-01-01

    Purpose: The idea of the paper is to study the influence of different alloying additions (Cu, Zr, Nb) on structuralrelaxation, crystallization, and improvement of soft magnetic properties in amorphous alloys of the type FeXSiBobtained by melt spinning technique.Design/methodology/approach: Magnetic and electric characteristics of the as quenched and successivelyannealed samples were determined at room temperature. Experiments were carried out by applying magneticpermeability measurements (Max...

  15. Crystallization behavior and magnetic properties in High Fe content FeBCSiCu alloy system

    International Nuclear Information System (INIS)

    High Fe content FeBCSiCu nanocrystalline alloys are prepared by annealing melt-spun amorphous ribbons with aim at increasing saturation magnetic flux density. Microstructures identified by XRD and TEM reveal that Cu addition inhibits the surface crystallization of Fe86B7C7 alloy and improve its glass-forming ability. Activation energy of crystallization calculated by Kissinger's equation indicates that both Cu and Si addition promotes the precipitation of α-Fe phase and improves the thermal stability. VSM and DC B–H loop tracer measurements show that the Fe85.5B7C6Si1Cu0.5 nanocrystalline alloy exhibits high saturation magnetic flux density of 1.8 T and low coercivity of 10 A/m, respectively. AC properties measured by AC B–H analyzer show this alloy exhibits low core loss of 0.35 W/kg at 1 T at 50 Hz. Low material cost and convenient productivity make the Fe85.5B7C6Si1Cu0.5 nanocrystalline alloy an economical application in industry. - Highlights: • Cu addition inhibits the surface crystallization and improves the GFA. • The competitive formation of Fe3C and α-Fe phase impedes the devitrification. • Fe85.5B7C6Si1Cu0.5 nanocrystalline alloy exhibits excellent magnetic properties. • The alloy system has an economical advantage and convenient productivity

  16. Effect of Al–5Ti–C Master Alloy on the Microstructure and Mechanical Properties of Hypereutectic Al–20%Si Alloy

    Directory of Open Access Journals (Sweden)

    Wanwu Ding

    2014-02-01

    Full Text Available Al–5Ti–C master alloy was prepared and used to modify hypereutectic Al–20%Si alloy. The microstructure evolution and mechanical properties of hypereutectic Al–20%Si alloy with Al–5Ti–C master alloy additions (0, 0.4, 0.6, 1.0, 1.6 and 2.0 wt% were investigated. The results show that, Al–5Ti–C master alloy (0.6 wt%, 10 min can significantly refine both eutectic and primary Si of hypereutectic Al–20%Si alloy. The morphology of the primary Si crystals was significantly refined from a coarse polygonal and star-like shape to a fine polyhedral shape and the grain size of the primary Si was refined from roughly 90–120 μm to 20–50 μm. The eutectic Si phases were modified from a coarse platelet-like/needle-like structure to a fine fibrous structure with discrete particles. The Al–5Ti–C master alloy (0.6 wt%, 30 min still has a good refinement effect. The ultimate tensile strength (UTS, elongation (El and Brinell hardness (HB of Al–20%Si alloy modified by the Al–5Ti–C master alloy (0.6 wt%, 10 min increased by roughly 65%, 70% and 51%, respectively, due to decreasing the size and changing the morphology on the primary and eutectic Si crystals. The change in mechanical properties corresponds to evolution of the microstructure.

  17. Microstructure, cold rolling, heat treatment, and mechanical properties of Mg-Li alloys

    Institute of Scientific and Technical Information of China (English)

    Haibin Ji; Guangchun Yao; Hongbin Li

    2008-01-01

    The magnesium-lithium (Mg-Li) alloy exhibits two phase structures between 5.7wt% and 10.3wt% Li contents, consisting of the a (hcp) Mg-rich and the β (bee) Li-rich phases, at room temperature. In the experiment, Mg-5Li-2Zn, Mg-9Li-2Zn,Mg-16Li-2Zn, Mg-22Li-2Zn, Mg-5Li-2Zn-2Ca, Mg-9Li-2Zn-2Ca, Mg-16Li-2Zn-2Ca, and Mg-22Li-2Zn-2Ca (wt%) were melted.During the melting process, the flux, which was composed of lithium chloride (LiCI) and lithium fluoride (LiF) in the proportion of 3:1 (mass ratio) and argon gas were used to protect the alloys from oxidation. The mierostructure, mechanical properties, and cold-rolling workability of the wrought alloys were studied. The crystal grain of the alloys (adding Ga) is fine. The hardness of the studied alloys decreases with an increase in element Li. The density of the studied alloys is in the range of 1.187 to 1.617 g/cm3 The reduction of the Mg-16Li-2Zn and Mg-22Li-2Zn alloys can exceed 85% at room temperature. The Mg-9Li-2Zn-2Ca alloy was heat treated at 300℃ for 8, 12, 16, and 24 h, respectively. The optimum heat treatment of the Mg-9Li-2Zn-2Ca alloy is 300~Cx12h by metallographic observation and by studying the mechanical properties of the alloys.

  18. Elastic properties of Pu metal and Pu-Ga alloys

    Energy Technology Data Exchange (ETDEWEB)

    Soderlind, P; Landa, A; Klepeis, J E; Suzuki, Y; Migliori, A

    2010-01-05

    We present elastic properties, theoretical and experimental, of Pu metal and Pu-Ga ({delta}) alloys together with ab initio equilibrium equation-of-state for these systems. For the theoretical treatment we employ density-functional theory in conjunction with spin-orbit coupling and orbital polarization for the metal and coherent-potential approximation for the alloys. Pu and Pu-Ga alloys are also investigated experimentally using resonant ultrasound spectroscopy. We show that orbital correlations become more important proceeding from {alpha} {yields} {beta} {yields} {gamma} plutonium, thus suggesting increasing f-electron correlation (localization). For the {delta}-Pu-Ga alloys we find a softening with larger Ga content, i.e., atomic volume, bulk modulus, and elastic constants, suggest a weakened chemical bonding with addition of Ga. Our measurements confirm qualitatively the theory but uncertainties remain when comparing the model with experiments.

  19. Elastic properties of Pu metal and Pu-Ga alloys

    Science.gov (United States)

    Söderlind, Per; Landa, Alex; Klepeis, J. E.; Suzuki, Y.; Migliori, A.

    2010-06-01

    We present elastic properties, theoretical and experimental, of Pu metal and Pu-Ga (δ) alloys together with ab initio equilibrium equation of state for these systems. For the theoretical treatment we employ density-functional theory in conjunction with spin-orbit coupling and orbital polarization for the metal and coherent-potential approximation for the alloys. Pu and Pu-Ga alloys are also investigated experimentally using resonant ultrasound spectroscopy. We show that orbital correlations become more important proceeding from α→β→γ plutonium, thus suggesting increasing f -electron correlation and a corresponding softening of the elastic moduli. For the δ-Pu-Ga alloys we find a softening with larger Ga content, i.e., atomic volume, bulk modulus, and elastic constants imply a weakened chemical bonding with addition of Ga. Our measurements confirm qualitatively the theory but uncertainties remain when comparing the model with experiments.

  20. Mechanical properties of modified low cobalt powder metallurgy Udimet 700 type alloys

    Science.gov (United States)

    Harf, Fredric H.

    1989-01-01

    Eight superalloys derived from Udimet 700 were prepared by powder metallurgy, hot isostatically pressed, heat treated and their tensile and creep rupture properties determined. Several of these alloys displayed properties superior to those of Udimet 700 similarly prepared, in one case exceeding the creep rupture life tenfold. Filter clogging by extracted gamma prime, its measurement and significance are discussed in an appendix.

  1. Electrical conductivity and mechanical properties of Cu-0.7wt% Cr and Cu-1.0wt% Cr alloys processed by severe plastic deformation

    Science.gov (United States)

    Kommel, L.; Pokatilov, A.

    2014-08-01

    As-cast Cu-0.7wt% Cr and Cu-1.0wt% Cr alloys were subjected to equal-channel angular pressing (ECAP), hard cyclic viscoplastic (HCV) deformation and post deformation heat treatment for receiving an ultrafine grained material with a combination of high strength, good wear resistance and high electric conductivity. Samples from Cu-0.7wt% Cr alloy were processed up to six passes and Cu-1wt% Cr alloy samples were processed up to four passes of ECAP via Bc route. HCV deformation of samples was conducted by frequency of 0.5 Hz for 20 cycles at tension-compression strain amplitudes of +/-0.05%, +/-0.1%, +/-0.5%, +/-1% and +/-1.5%, respectively. During HCV deformation, as-cast Cu-0./wt% Cr alloy show fully viscoelastic behavior at strain/stress amplitude of +/-0.05% while ECAP processed material show the same behavior at strain amplitude of +/-0.1%. The Young modulus was increased from ~120 GPa up to ~150 GPa. The results illustrated that specific volume wear decrease with increasing of hardness but the measured coefficient of friction (COF ~ 0.6) was approximately the same for all samples at the end of wear testing. The hardness after ECAP for 6 passes by Bc route was 192HV0.1 and electric conduction 74.16% IACS, respectively. By this the as-cast Cu-0./wt% Cr alloy (heat treated at 1000 °C for 2h) has microhardness ~70HV0.1 and electrical conductivity of ~40% IACS. During aging at the temperatures in the interval of 250-550 °C for 1h the hardness and electrical conductivity were stabilized to mean values of 120+/-5HV0.1 and to 93.4+/-0.3% IACS, respectively. The hardness and electric conductivity took decrease by temperature increase over ~550 °C, respectively. The results of present experimental investigation show that UFG Cu- 0.7wt% Cr alloy with compare to Cu-1.0% Cr alloy is a highly electrical conductive and high temperature wear resistant material for using in electrical industry.

  2. Evaluation of the mechanical properties of microarc oxidation coatings and 2024 aluminium alloy substrate

    CERN Document Server

    Xue Wen Bin; Deng Zhi Wei; Chen Ru Yi; Li Yong Liang; Zhang Ton Ghe

    2002-01-01

    A determination of the phase constituents of ceramic coatings produced on Al-Cu-Mg alloy by microarc discharge in alkaline solution was performed using x-ray diffraction. The profiles of the hardness, H, and elastic modulus, E, across the ceramic coating were determined by means of nanoindentation. In addition, a study of the influence of microarc oxidation coatings on the tensile properties of the aluminium alloy was also carried out. The results show that the H-and E-profiles are similar, and both of them exhibit a maximum value at the same depth of coating. The distribution of the alpha-Al sub 2 O sub 3 phase content determines the H- and E-profiles of the coatings. The tensile properties of 2024 aluminium alloy show less change after the alloy has undergone microarc discharge surface treatment.

  3. Tensile and impact properties of General Atomics 832864 heat of V-4Cr-4Ti alloy

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, H.; Nowicki, L.J.; Gazda, J.; Billone, M.C.; Smith, D.L. [Argonne National Lab., IL (United States); Johnson, W.R.; Trester, P. [General Atomics, San Diego, CA (United States)

    1998-09-01

    A 1300-kg heat of V-4Cr-4Ti alloy was procured by General Atomics (GA) for the DIII-D radiative divertor program. To determine the mechanical properties of this alloy, tensile and Charpy tests were conducted on specimens prepared from pieces of 4.8-mm-thick as-rolled plates, a major product form for the DIII-D application. The tensile tests were conducted at three temperatures, 26, 280 and 380 C, the last two being the anticipated peak temperatures during DIII-D boronization and postvent bake-out, respectively. Results from these tests show that the tensile and impact properties of the 832864 heat are comparable to those of the other smaller V-(4-5)Cr-(4-5)Ti alloy heats previously developed by the US Fusion Materials Program and that scale-up of vanadium alloy production can be successfully achieved as long as reasonable process control is implemented.

  4. Study of thermodynamic properties of Np-Al alloys in molten LiCl-KCl eutectic

    Energy Technology Data Exchange (ETDEWEB)

    Mendes, E.; Soucek, P.; Malmbeck, R.; Glatz, J. P. [Institute for Transuranium Elements, Karlsruhe (Germany); Caravaca, C. [CIEMAT, DE/DFN/URAA, Madrid (Spain)

    2008-08-15

    This work is focused on chemical characterisation and determination of thermodynamic properties of Np-Al alloys. The alloys are formed on a solid Al electrode during Np electrodeposition in molten LiCl-KCl Eutectic. Open circuit potential measurements, after small depositions of Np metal onto the Al electrode were used to determine thermodynamic properties of the Np-Al alloys formed (G, H, S, activity of Np in Al) by an e.m.f. method. Galvanostatic electrolyses were carried out on an Al plates. Stable Np-Al deposit was obtained and identified, by XRD analysis, as a mixture NpAl{sub 3} and NpAl{sub 4} alloys.

  5. Effect of process parameters on properties of Al-Si alloys cast by Rapid Slurry Formation (RSF) technique

    International Nuclear Information System (INIS)

    Rapid slurry formation is a semi-solid metal forming technique, which is based on a so-called solid enthalpy exchange material (EEM). It is a fascinating technology offering the opportunity to manufacture net-shaped metal components of complex geometry in a single forming operation. At the same time, high mechanical properties can be achieved due to the unique microstructure and flow behaviour. The major process parameters used in the RSF process are rotation speed of the EEM, melt superheat, amount of EEM added (determining fs), and holding time. The process parameters can be well controlled with clear effects on the microstructure. There is a lack of theoretical modelling of the morphological evolution in these two-phase slurries.

  6. Manufacturing of Titanium and Aluminium Light alloys by powder metallurgy

    OpenAIRE

    Gordo Odériz, Elena; Ruiz Navas, Elisa María

    2008-01-01

    The Group of Powder Technology (GTP) of the University Carlos III has a wide experience in the development and processing of new materials by Powder Metallurgy (PM). The mechanical alloying (MA) process, or high energy milling, allows the attainment of powders with compositions impossible to produce by other techniques, with improved properties for structural applications, where mechanical properties are the main requirement, and for applications where other specific properties are needed....

  7. Optical and Electronic Properties of 2D Graphitic Carbon-Nitride and Carbon Enriched Alloys

    Science.gov (United States)

    Therrien, Joel; Li, Yancen; Schmidt, Daniel; Masaki, Michael; Syed, Abdulmannan

    The two-dimensional form of graphitic carbon-nitride (gCN) has been successfully synthesized using a simple CVD process. In it's pure form, the carbon to nitrogen ratio is 0.75. By adding a carbon bearing gas to the growth environment, the C/N ratio can be increased, ultimately reaching the pure carbon form: graphene. Unlike attempts at making a 2D alloy system out of BCN, the CN system does not suffer from phase segregation and thus forms a homogeneous alloy. The synthesis approach and electronic and optical properties will be presented for the pure gCN and a selection of alloy compositions.

  8. Influence of solution treatment on microstructure, mechanical and corrosion properties of Mg-4Zn alloy

    OpenAIRE

    Hongmin Jia; Xiaohui Feng; Yuansheng Yang

    2015-01-01

    The solution treatment parameters, mechanical properties and corrosion behavior of binary Mg-4Zn alloy were investigated. The results showed that after the solution treatment at 335 °C for 16 h, Mg-4Zn alloy had an ultimate tensile strength of 184.13 MPa and elongation of 9.43%. Furthermore, the corrosion resistance was evaluated by electrochemical measurements and immersion tests in 3.5% NaCl solution. The results revealed that the corrosion current density of the solution treatment Mg alloy...

  9. Microstructure and properties of PbCa grade alloys for starting battery grids

    OpenAIRE

    Wesołowski, J.; S. Malara; L. Ciura; W. Kazana

    2016-01-01

    The paper presents results of the studies into microstructure and mechanical properties of PbCa grade alloys for starting battery grids. Three lead-calcium alloys with alloy additions of aluminium, tin, silver and magnesium were studied. Lead alloys were produced in laboratory tests from industrial master alloys and pure elements. The examined alloys have monophase microstructure of tin solid solution in the lead. The range between liquidus and solidus temperatures is c.a. 10 °C. The mechanic...

  10. Structural, mechanical and electrical properties of alloys in ternary Ag-Bi-Zn system

    Energy Technology Data Exchange (ETDEWEB)

    Minic, D. M.; Premovic, M. M.; Zivkovic, D. T.; Manasijevic, D. M.; Dimie, M. Z.; Petrovic, Z. R.; Markovic, S. M.

    2015-07-01

    Structural, mechanical and electrical properties of selected alloys in ternary Ag-Bi-Zn system are presented in this paper. Chosen alloys were investigated using X-Ray Diffraction (XRD), light optical microscopy, Scanning Electron Microscopy combined with Energy Dispersive Spectrometry (SEM-EDS), as well as by electrical conductivity and Brinell hardness measurements. Isolines of electrical conductivity and hardness for the entire Ag-Bi-Zn system were calculated using regression models. (Author)

  11. Torsional and axial damping properties of the AZ31B-F magnesium alloy

    Science.gov (United States)

    Anes, V.; Lage, Y. E.; Vieira, M.; Maia, N. M. M.; Freitas, M.; Reis, L.

    2016-10-01

    Damping properties for the AZ31B-F magnesium alloy were evaluated for pure axial and pure shear loading conditions at room temperature. Hysteretic damping results were measured through stress-strain controlled tests. Moreover, the magnesium alloy viscous damping was measured with frequency response functions and free vibration decay, both results were obtained by experiments. The axial and shear damping ratio (ASDR) has been identified and described, specifically for free vibration conditions.

  12. Microstructure and mechanical properties of laser melting deposited Ti2Ni3Si/NiTi Laves alloys

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Two Ti2Ni3Si/NiTi Laves phase alloys with chemical compositions of Ni-39Ti-11 Si and Ni-42Ti-8Si (%, mole fraction, the same below), respectively, were fabricated by the laser melting deposition manufacturing process, aiming at studying the effect of Ti,Si contents on microstructure and mechanical properties of the alloys. The Ni-39Ti-llSi alloy consisting of Ti2Ni3Si primary dendrites and Ti2Ni3Si/NiTi eutectic matrix is a conventional hypereutectic Laves phase alloy while the Ni-42Ti-8Si alloy being made up of NiTi primary dendrites uniformly distributed in Ti2Ni3Si/NiTi eutectic is a new hypoeutectic alloy. Mechanical properties of the alloys were investigated by nano-indentation test. The results show that the decrease of Si and the increase of Ti contents change the microstructures of the alloys from hypereutectic to hypoeutectic, which influences the mechanical properties of the alloys remarkably. Corrosion behaviors of the alloys were also evaluated by potentiodynamic anodic polarization curves.

  13. Microstructure and the properties of FeCoCuNiSnx high entropy alloys

    International Nuclear Information System (INIS)

    Highlights: ► Based on a new alloying design idea, new FeCoCuNiSnx alloys are prepared. ► The crystal structure of alloys is a single FCC solution when Sn content is small. ► The elongation strain and tensile strength of the alloy reach 19.8% and 633 MPa. - Abstract: FeCoCuNiSnx high-entropy alloys (x denotes the adding the elements amount in atomic percentage) are prepared by an arc furnace. Their microstructure and mechanical properties are investigated. The results show that the alloys have a single FCC solution when Sn content is small, the microstructure of the alloys with increasing Sn content is FCC solution and Cu81Sn22 intermetallic compounds. The alloys possess the high strength and the plasticity. When Sn content is between 0.05 and 0.07, the maximum elongation strain and the maximum tensile strength can reach 19.8% and 633 MPa, respectively. The adding of Sn leads to the increase of tensile strength.

  14. The effect warming time of mechanical properties and structural phase aluminum alloy nickel

    International Nuclear Information System (INIS)

    Ferrous aluminum alloys as fuel cladding will experience the process of heat treatment above the recrystallization temperature. Temperature and time of heat treatment will affect the nature of the metal. Heating time allows will affect change in mechanical properties, thermal and structure of the metal phase. This study aims to determine the effect of time of heat treatment on mechanical properties and phase metal alloys. Testing the mechanical properties of materials, especially violence done by the method of Vickers. Observation of microstructural changes made by metallographic-optical and phase structure were analyzed Based on the x-ray diffraction patterns Elemental analysis phase alloy compounds made by EDS-SEM. Test results show the nature of violence AlFeNiMg alloy by heating at 500°C with a warm-up time 1 hour, 2 hours and 3 hours respectively decreased range 94.4 HV, 87.6 HV and 85.1 HV. The nature of violence AlFeNi alloy showed a decrease in line with the longer heating time. Metallographic-optical observations show the microstructural changes with increasing heating time. Microstructure shows the longer the heating time trend equi axial shaped grain structure of growing and the results showed a trend analyst diffraction pattern formation and phase θ α phase (FeAl3) in the alloy. (author)

  15. The Effect of Cold Work on Properties of Alloy 617

    Energy Technology Data Exchange (ETDEWEB)

    Richard Wright

    2014-08-01

    Alloy 617 is approved for non-nuclear construction in the ASME Boiler and Pressure Vessel Code Section I and Section VIII, but is not currently qualified for nuclear use in ASME Code Section III. A draft Code Case was submitted in 1992 to qualify the alloy for nuclear service but efforts were stopped before the approval process was completed.1 Renewed interest in high temperature nuclear reactors has resulted in a new effort to qualify Alloy 617 for use in nuclear pressure vessels. The mechanical and physical properties of Alloy 617 were extensively characterized for the VHTR programs in the 1980’s and incorporated into the 1992 draft Code Case. Recently, the properties of modern heats of the alloy that incorporate an additional processing step, electro-slag re-melting, have been characterized both to confirm that the properties of contemporary material are consistent with those in the historical record and to increase the available database. A number of potential issues that were identified as requiring further consideration prior to the withdrawal of the 1992 Code Case are also being re-examined in the current R&D program. Code Cases are again being developed to allow use of Alloy 617 for nuclear design within the rules of the ASME Boiler and Pressure Vessel Code. In general the Code defines two temperature ranges for nuclear design with austenitic and nickel based alloys. Below 427°C (800°F) time dependent behavior is not considered, while above this temperature creep and creep-fatigue are considered to be the dominant life-limiting deformation modes. There is a corresponding differentiation in the treatment of the potential for effects associated with cold work. Below 427°C the principal issue is the relationship between the level of cold work and the propensity for stress corrosion cracking and above that temperature the primary concern is the impact of cold work on creep-rupture behavior.

  16. Magnetic properties and fine structure of Fe-Co alloys with vanadium and chromium additions

    Energy Technology Data Exchange (ETDEWEB)

    Dzhavadov, D.M.; Tyapkin, Yu.D. (Tsentral' nyj Nauchno-Issledovatel' skij Inst. Chernoj Metallurgii, Moscow (USSR))

    1982-11-01

    Magnetic properties of alloys iron-cobalt, iron-cobalt-vanadium, iron-cobalt-chromium have been investigated. Measurements of permeability, coercive force Hsub(c), B/sub 25/ and B/sub 100/ magnetic saturation on alloy samples on which electrical resistance previously is measured and fine crystalline structure is studied by the methods of transmission electron microscopy, diffusion scattering of X rays and electrons and NGR. Comparison of properties and structure makes possible to bind Hsub(c), B permeability values with such structure features as a long-range order of B2 type, short-range decomposition order and Cottrell clouds formation in vanadium containing alloys and a complex short-range order in chromium-containing alloys.

  17. Surface Composition and Corrosion Property of TiNi Alloys Coated with Tantalum Films

    Institute of Scientific and Technical Information of China (English)

    Yan CHENG; Wei CAI; Liancheng ZHAO

    2004-01-01

    Multi-arc ion plating method was employed to coat TiNi alloys with Ta in order to improve radiopacity and corrosion resistance property. The surface composition, corrosion resistance property and Ni ions release amount of TiNi alloys coated with Ta films compared with TiNi alloys, are investigated by means of X-ray photoelectron spectrometry (XPS), electrochemical measurements and atomic absorption spectrophotometry (AAS), respectively. The results show that the coated surface composition is composed of Ta and O and the corrosion resistance is improved, whereas the Ni ions release amount of the coated sample is lower than that of the uncoated samples in the whole immersion period, indicating that Ta coating can improve the biocompatibility of TiNi alloys.

  18. Enhancing Microstructure and Mechanical Properties of AZ31-MWCNT Nanocomposites through Mechanical Alloying

    Directory of Open Access Journals (Sweden)

    J. Jayakumar

    2013-01-01

    Full Text Available Multiwall carbon nanotubes (MWCNTs reinforced Mg alloy AZ31 nanocomposites were fabricated by mechanical alloying and powder metallurgy technique. The reinforcement material MWCNTs were blended in three weight fractions (0.33%, 0.66%, and 1% with the matrix material AZ31 (Al-3%, zinc-1% rest Mg and blended through mechanical alloying using a high energy planetary ball mill. Specimens of monolithic AZ31 and AZ31-MWCNT composites were fabricated through powder metallurgy technique. The microstructure, density, hardness, porosity, ductility, and tensile properties of monolithic AZ31 and AZ31-MWCNT nano composites were characterized and compared. The characterization reveals significant reduction in CNT (carbon nanoTube agglomeration and enhancement in microstructure and mechanical properties due to mechanical alloying through ball milling.

  19. Corrosion properties of high silicon iron-based alloys in nitric acid

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The effect of copper and rare-earth elements on corrosion behavior of ~iigh silicon iron-based alloys in nitric acid was studied by means of static and loading current corrosion experiments. The anodic polarization curve was also made to discuss the corrosion mechanism. The examination on alloy microstructure and SEM corrosion pattern showed that when silicon content reached 14.5%, the Fe3Si phase appeared and the primary structure of the iron-base alloy was ferrite. When adding 4.57% copper in the iron alloy, its corrosion resistance in static diluted sulfuric acid was improved while its corrosion resistance and electrochemical corrosion properties in the nitric acid were decreased. In contrast, the addition of rare earth elements could improve the corrosion properties in all above conditions including in static diluted sulfuric acid and in nitric acid.

  20. Changes of Tempering Microstructure and Properties of Fe-Cr-V-Ni-Mn-C Cast Alloys

    Institute of Scientific and Technical Information of China (English)

    LIU Yan-xia; MA Yong-qing; WANG Yue-hua; ZHANG Zhan-ping; ZHANG Yang

    2004-01-01

    The changes of tempering microstructure and properties of Fe-Cr-V-Ni-Mn-C cast alloys with martensite matrix and much retained austenite are studied. The results showed that when tempering at 200℃ the amount of retained austenite in the alloys is so much that is nearly to as-cast, and a lot of retained austenite decomposes when tempering at 350℃ and the retained austenite decomposes almost until tempering at 560℃. When tempering at 600℃, the retained austenite in the alloys all decomposes. At 560℃ the hardness is highest due to secondary hardening. The effect of nickel and manganese on the microstructure and properties of Fe-Cr-V-C cast alloy were also studied. The results show that the Fe-Cr-V-C cast alloy added nickel and manganese can obtain martensite matrix and much retained austenite microstructure, and nickel can also prevent pearlite transformation. With the increasing content of nickel and manganese, the hardness of as-cast alloy will decreases gradually, so one can improve the hardness of alloy by tempering process. When the content of nickel and manganese is 1.3~1.7%, the hardness of secondary hardening is the highest (HRC64). But when the content of nickel and manganese increase continually, the hardness of secondary hardening is low slightly, and the tempering temperature of secondary hardening rises.

  1. Effect of thermomechanical treatment on mechanical properties and electrical conductivity of a CuCrZr alloy

    Indian Academy of Sciences (India)

    G Durashevich; V Cvetkovski; V Jovanovich

    2002-02-01

    The CuCrZr alloy undergoes processes of precipitation during ageing. Besides precipitation hardening the strength is affected by cold deformation which is performed before and after ageing. The cold deformation (1) before ageing accelerates the process of strength hardening, since it induces higher rate of precipitation from the saturated -solid solution. Cold deformation (2) after ageing primarily affects the alloy strength. In this paper the results of the effect of thermomechanical treatment on mechanical properties and electrical conductivity of a CuCrZr alloy are presented. The aim of the paper was to evaluate the most suitable combination of thermomechanical treatment and alloy properties.

  2. Magnetic properties of Cr telluride-selenide alloys

    Energy Technology Data Exchange (ETDEWEB)

    Mankovsky, Sergey; Polesya, Svetlana; Ebert, Hubert [Dept. Chemie und Biochemie, Universitaet Muenchen, Butenandtstr. 5-13, D-81377 Muenchen (Germany); Huang, Zhong-Le; Bensch, Wolfgang [Institute for Anorganic Chemistry, Olshausenstr. 40, D-24098, Kiel (Germany)

    2007-07-01

    Results of a theoretical study of the magnetic properties of Cr telluride-selenide alloys having trigonal crystal structure are presented in comparison with experimental results. Both ground state and temperature-dependent magnetic properties of Cr{sub 1-{delta}}Te and Cr{sub x}(Te{sub {alpha}}Se{sub {beta}}){sub 2} (with ratio {alpha}:{beta}=7:1,6:2,5:3) have been investigated in a wide region of chromium content. For the alloys Cr{sub x}(Te{sub {alpha}}Se{sub {beta}}){sub 2} a transition to the state with antiferromagnetic order in a fully occupied sub-lattice and with no order in a partially occupied sub-lattice was obtained. For the alloys Li{sub x}Cr{sub 0.5}Ti{sub 0.75}Se{sub 2}, a non-monotonic dependence of structural and magnetic properties have been found upon increase of Li concentration x, that is in agreement with experimental results. The ground state properties have been studied on the basis of electronic structure calculations using the Korringa-Kohn-Rostoker (KKR) band structure method combined with the CPA alloy theory. Using Monte Carlo simulations we obtained the magnetic configuration at T=0 K and studied the magnetic properties at T>0 K as well. The required exchange coupling parameters were obtained from our ab-initio electronic structure calculations.

  3. Zirconium alloys produced by recycling zircaloy tunings

    Energy Technology Data Exchange (ETDEWEB)

    Gamba, N.S. [Instituto de Investigaciones en Catálisis y Petroquímica, INCAPE (FIQ, UNL–CONICET), Santiago del Estero 2829, 3000 Santa Fe (Argentina); Carbajal-Ramos, I.A. [Centro Atómico Bariloche, CNEA e Instituto Balseiro, Universidad Nacional de Cuyo, Av. Bustillo 9500, 8400 Bariloche (Argentina); Ulla, M.A.; Pierini, B.T. [Instituto de Investigaciones en Catálisis y Petroquímica, INCAPE (FIQ, UNL–CONICET), Santiago del Estero 2829, 3000 Santa Fe (Argentina); Gennari, F.C., E-mail: gennari@cab.cnea.gov.ar [Centro Atómico Bariloche, CNEA e Instituto Balseiro, Universidad Nacional de Cuyo, Av. Bustillo 9500, 8400 Bariloche (Argentina)

    2013-11-25

    Highlights: •Zr–Ti alloys were successfully produced by two-step procedure. •Zircaloy tunings were used as a valuable source of Zr. •Zircaloy tunings and Ti powders was milled under hydrogen to produce hydride powders. •Hydride powders were decomposed by heating at 900 °C to synthesize the Zr-based alloy. •The procedure could be extended to the production of other Zr-based alloys. -- Abstract: Zircaloy chips were recycled to successfully produce Zr–Ti alloys with bcc structure and different compositions. The procedure developed involves two steps. First, the reactive mechanical alloying (RMA) of the zircaloy tunings and Ti powders was performed to produce metal hydride powders, with a high refinement of the microstructure and a Zr–Ti homogeneous composition. Second, the metal hydride powders were thermally decomposed by heating up to 900 °C to synthesize the Zr-based alloy with a selected composition. The change in the nature of the powders from ductile to brittle during milling avoids both cold working phenomena between the metals and the use of a control agent. A minimum milling time is necessary to produce the solid solution with the selected composition. The microstructure and structure of the final alloys obtained was studied. The present procedure could be extended to the production of Zr-based alloys with the addition of other metals different from Ti.

  4. Effects of Rare Earths on Properties of Ti-Zr-Cu-Ni Base Brazing Filler Alloys

    Institute of Scientific and Technical Information of China (English)

    Ma Tianjun; Kang Hui; Wu Yongqin; Qu Ping

    2004-01-01

    The effects of the addition of rare earths on the properties of Ti-Zr-Cu-Ni base brazing filler alloys and the mechanical microstructure and properties were studied for the brazed-joints in the vacuum brazing of TC4 by comparing synthetical properties of two kinds of filler metals.The results indicate that the filler metals added with rare earths have lower melting point, better wettability and higher mechanical properties in the brazing joints.

  5. Synthesis of ternary nitrides by mechanochemical alloying

    DEFF Research Database (Denmark)

    Jacobsen, C.J.H.; Zhu, J.J.; Lindelov, H.;

    2002-01-01

    Ternary metal nitrides ( of general formula MxM'N-y(z)) attract considerable interest because of their special mechanical, electrical, magnetic, and catalytic properties. Usually they are prepared by ammonolysis of ternary oxides (MxM'O-y(m)) at elevated temperatures. We show that ternary...... transition metal nitrides are also obtained by nitridation of the corresponding ternary carbide at 823 K. This transformation appears to occur by solid-state diffusion of carbide and nitride ions. To establish more general synthesis schemes for ternary nitrides, we have focused on the preparation of ternary...... nitrides by mechanochemical alloying of a binary transition metal nitride (MxN) with an elemental transition metal. In this way, we have been able to prepare Fe3Mo3N and Co3Mo3N by ball-milling of Mo2N with Fe and Co, respectively. The transformation sequence from the starting materials ( the binary...

  6. Electonic properties of hydrogenated amorphous silicon-germanium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Bullot, J.; Galin, M.; Gauthier, M. (Universite de Paris-Sud, Orsay (France)); Bourdon, B. (CIT-Alcatel Transmission, Marcoussis (France))

    1983-06-01

    The electronic properties of some binary hydrogenated amorphous silicon-germanium alloys a-Sisub(x)Gesub(1-x):H in the silicon rich region (x > 0.6) are investigated. Experimental evidence is presented of photo-induced effects similar to those described in Si:H (Staebler-Wronski effect). The electronic properties are then studied from the dual point of view of the germanium content dependence and of the photo and thermal histories of the films. The dark conductivity changes between the annealed state and the light-soaked state are interpreted in terms of the variation of the temperature coefficient of the Fermi level. The photoconductivity efficiency is shown to remain close to that of a-Si:H for 1 > x >= 0.9 and to strongly decrease when the germanium content is further increased: the photoresponse of the Sisub(0.62)Gesub(0.38) alloy is 10/sup 4/ times smaller than that of a-Si:H. This deterioration of the photoconductive properties is explained in terms of the increase of the density of gap states following Ge substitution. This conclusion is based on the study of the width of the exponential absorption edge and on the results of photoconductivity time response studies. The latter data are interpreted by means of the model of Rose of trapping and recombination kinetics and it is found that for x approximately 0.6 the density of states at 0.4-0.5 eV below the mobility edge is 7 x 10/sup 17/ eV/sup -1/ cm/sup -3/ as compared to 2.4 x 10/sup 16/ eV/sup -1/ cm/sup -3/ for x = 0.97.

  7. Producing titanium-niobium alloy by high energy beam

    International Nuclear Information System (INIS)

    The research is involved in producing a Ti-Nb alloy surface layer on titanium substrate by high energy beam method, as well as in examining their structures and mechanical properties. Applying electron-beam cladding it was possible to produce a Ti-Nb alloy surface layer of several millimeters, where the niobium concentration was up to 40% at. and the structure itself could be related to martensite quenching structure. At the same time, a significant microhardness increase of 3200-3400 MPa was observed, which, in its turn, is connected with the formation of martensite structure. Cladding material of Ti-Nb composition could be the source in producing alloys of homogeneous microhardness and desired concentration of alloying niobium element

  8. Producing titanium-niobium alloy by high energy beam

    Energy Technology Data Exchange (ETDEWEB)

    Sharkeev, Yu. P., E-mail: sharkeev@ispms.tsc.ru [Institute of Strength Physics and Materials Science, SB RAS, 2/4 Akademicheski Prosp., Tomsk, 634055 (Russian Federation); National Research Tomsk Polytechnic University, 30 Lenin Av., Tomsk, 634050 (Russian Federation); Golkovski, M. G., E-mail: golkoski@mail.ru [Budker Institute of Nuclear Physics, 11 Akademika Lavrentiev Prosp., Novosibirsk, 630090 (Russian Federation); Glukhov, I. A., E-mail: gia@ispms.tsc.ru; Eroshenko, A. Yu., E-mail: eroshenko@ispms.tsc.ru; Fortuna, S. V., E-mail: s-fortuna@mail.ru [Institute of Strength Physics and Materials Science, SB RAS, 2/4 Akademicheski Prosp., Tomsk, 634055 (Russian Federation); Bataev, V. A., E-mail: bataev@vadm.ustu.ru [Novosibirsk State Technical University, 20 K. Marx Prosp., Novosibirsk, 630073 (Russian Federation)

    2016-01-15

    The research is involved in producing a Ti-Nb alloy surface layer on titanium substrate by high energy beam method, as well as in examining their structures and mechanical properties. Applying electron-beam cladding it was possible to produce a Ti-Nb alloy surface layer of several millimeters, where the niobium concentration was up to 40% at. and the structure itself could be related to martensite quenching structure. At the same time, a significant microhardness increase of 3200-3400 MPa was observed, which, in its turn, is connected with the formation of martensite structure. Cladding material of Ti-Nb composition could be the source in producing alloys of homogeneous microhardness and desired concentration of alloying niobium element.

  9. Microstructural and mechanical properties of binary Ni–Si eutectic alloys

    International Nuclear Information System (INIS)

    Highlights: • Ni80Si20, Ni70Si30, Ni55Si45 and Ni45Si55 were prepared by arc melting method. • The maximum microhardness value of 1126 HV obtained for Ni70Si30 alloy. • The microhardness values decreases with increase of Si/Ni ratio. • Ni80Si20 and Ni55Si45 are soft ferromagnetic, Ni70Si30 and Ni45Si55 are paramagnetic. - Abstract: In the present work, Ni–Si eutectic alloys with nominal compositions of Ni80Si20, Ni70Si30, Ni55Si45 and Ni45Si55 (Ni and Si with the purity of 99.99%) were prepared by arc melting method under vacuum/argon atmosphere. The effects of Si/Ni ratio on the microstructural properties, thermal transformation behavior, micro-hardness and magnetic properties of the Ni–Si eutectic alloys were investigated. These alloys were characterized by X-ray diffraction (XRD), optical microscopy (OM), scanning electron microscopy (SEM), differential thermal analysis (DTA), Vickers microhardness measurement and Vibrating Sample Magnetometer (VSM). The phases expected according to Ni–Si phase diagram for conventional solidified eutectic Ni–Si alloys are considerably consistent with phase detected by XRD in this study. The quantitative results confirm that the chemical composition of the alloys very close to eutectic compositions and the microstructures are in typical lamellar eutectic morphology. The maximum microhardness value of 1126 HV obtained for Ni70Si30 alloy which has highest melting temperature amongst Ni–Si eutectics. The microhardness values decreases with increase of Si/Ni ratio. Ni80Si20 and Ni55Si45 alloys are soft ferromagnetic, Ni70Si30 and Ni45Si55 alloys are paramagnetic with no magnetic saturation

  10. Effect of aluminum on microstructure and property of Cu–Ni–Si alloys

    International Nuclear Information System (INIS)

    The effect of aluminum on the microstructure and properties of Cu–Ni–Si alloys has been investigated using hardness test, electrical conductivity measurement, optical microscopy, X-ray diffraction analysis, scanning electron microscopy and transmission electron microscopy. Compared with Cu–Ni–Si alloy, Cu–Ni–Si–Al alloy had finer grains. After homogenization treatment at 940 °C for 4 h, hot rolling by 80% at 850 °C, solution treatment at 970 °C for 4 h, cold rolling by 50% and ageing treatment at 450 °C for 60 min, properties better than Cu–Ni–Si alloy have been obtained in Cu–Ni–Si–Al alloy: hardness was 343 HV, electrical conductivity was 28.1% IACS, tensile strength was 1080 MPa, yield strength was 985 MPa, elongation percentage was 3.1% and stress relaxation rate was 9.83% (as tested at 150 °C and loading for 100 h). β-Ni3Si and δ-Ni2Si formed during the ageing process and the crystal orientation relationship between matrix and precipitates was : (02-bar 2-bar )Cu (01-bar 1-bar )β (010)δ, [100]Cu [100]β [001]δ; (111-bar )Cu (111-bar )β (02-bar 1)δ, [112]Cu [112]β [012]δ. Addition of Al promoted the precipitation, and effectively enhanced the anti-stress relaxation property. Quasi-cleavage fracture with shallow dimples appeared in designed Cu–Ni–Si–(Al) alloy

  11. Crystallization kinetics and magnetic properties of FeSiCr amorphous alloy powder cores

    Science.gov (United States)

    Xu, Hu-ping; Wang, Ru-wu; Wei, Ding; Zeng, Chun

    2015-07-01

    The crystallization kinetics of FeSiCr amorphous alloy, characterized by the crystallization activation energy, Avrami exponent and frequency factor, was studied by non-isothermal differential scanning calorimetric (DSC) measurements. The crystallization activation energy and frequency factor of amorphous alloy calculated from Augis-Bennett model were 476 kJ/mol and 5.5×1018 s-1, respectively. The Avrami exponent n was calculated to be 2.2 from the Johnson-Mehl-Avrami (JMA) equation. Toroid-shaped Fe-base amorphous powder cores were prepared from the commercial FeSiCr amorphous alloy powder and subsequent cold pressing using binder and insulation. The characteristics of FeSiCr amorphous alloy powder and the effects of compaction pressure and insulation content on the magnetic properties, i.e., effective permeability μe, quality factor Q and DC-bias properties of FeSiCr amorphous alloy powder cores, were investigated. The FeSiCr amorphous alloy powder cores exhibit a high value of quality factor and a stable permeability in the frequency range up to 1 MHz, showing superior DC-bias properties with a "percent permeability" of more than 82% at H=100 Oe.

  12. Microstructural evolution and thermophysical property evaluation of Th-U alloys

    International Nuclear Information System (INIS)

    Thorium-uranium alloy fuel has not received much research attention mainly because of easy availability of uranium and military incentive offered by U-Pu cycle. Moreover, (i) lack of a consistent systematic effort to develop the alloys and define the limitations of these fuels, (ii) dearth of initiatives to define its microstructures that can result from composition and fabrication variables are prime reasons for this system not having witnessed much developmental research endeavour. Hence, it seems prudent to explore few compositions selected from thorium-uranium phase diagram keeping two primary objectives in view viz. (i) establishing its microstructural features and to study the variations in those, if any, brought about by processing variables etc. and (ii) to assess few thermal properties relevant to fuel applications. This experimental work aims at addressing gap in research on thorium-uranium alloys. Selected compositions of thorium-uranium alloy have been taken for microstructural study and evaluation of thermophysical properties. Based on the microstructural features and thermophysical property evaluation it is seen that high thorium Th-U alloys have appreciable thermal conductivity and low thermal expansion coefficient. It can reasonably be concluded that high thorium Th-U alloy can be used for possible nuclear fuel application in reactors provided other factors (e.g. reactor physics, post irradiation examinations etc.) are also seen to be favourable. (author)

  13. Mechanical properties and structure of magnesium alloy AS31

    Directory of Open Access Journals (Sweden)

    A. Hanus

    2008-07-01

    Full Text Available Contemporary materials should possess high mechanical properties, physical and chemical, as well as technological ones, to ensure long and reliable use. The non-ferrous metals alloys used nowadays, including the magnesium alloys, meet the above-mentioned requirements and expectations regarding the contemporary materials.Magnesium alloys are primarily used in aeronautical and automobile industry in wide variety of structural characteristics because of their favorable combination of tensile strength (160 to 365 MPa, elastic modulus (45 GPa, and low density (1 740 kg/m3, which is two-thirds that of aluminum. Magnesium alloys have high strength-to-weight ratio (tensile strength/density, comparable to those of other structural metals. [1-6]Knowledge of the relaxation properties of metal materials at high temperatures is necessary for the verification of susceptibility of castings to the creation of defects during the production process. Temperature limits of materials where highest tension values are generated may be detected with tensile tests under high temperatures. The generated tensions in the casting are a cause of the creation and development of defects. At acoustic emission (hereinafter called the "AE" use, tensile tests at high temperatures may, among other things, be used for analysis of the AE signal sources and set, in more detail, the temperature limit of elastic-plastic deformations existence in the material under examination. The results of the temperature drop where tension at casting cooling is generated or its release at heating are basic data for controlled cooling mode (and temperature of casting knocking out of the form as well as necessary for the thermal mode for the casting tension reduction. [7-9]Knowledge of elastic-plastic properties at elevated temperatures is often important for complex evaluation of magnesium alloys. Objective of the work was focused on determination of changes of elastic-plastic properties of magnesium

  14. Effects of AI Addition on the Thermoelectric Properties of Zn-Sb Based Alloys

    Institute of Scientific and Technical Information of China (English)

    CUI Jiaolin; LIU Xianglian; YANG Wei; CHEN Dongyong; MAO Liding; QIAN Xin

    2009-01-01

    The β-Zn4Sb3, emerged as a compelling p-type thermoelectric material, is widely used in heat-electricity conversion in the 400-650 K range. In order to probe the effects of slight doping on the crystal structure and physical properties, we prepared the samples of Al-added Zn-Sb based alloys by spark plasma sintering and evaluated their microstructures and thermoelectric properties. After a limited Al addition into the Zn-Sb based alloys we observed many phases in the alloys, which include a major phase β-Zn4Sb3,intermetallic phases ZnSb and AISb. The major β-Zn4Sb3 phase plays a fundamental role in controlling the thermoelectric performance, the precipitated phases ZnSb and AISb are of great importance to tailor the transport properties, such as the gradual enhancement of lattice thermal conductivity, in spite of an increased phonon scattering in additional grain boundaries. The highest thermoelectric figure of merit of 0.55 is obtained for the alloy with a limited AI addition at 653 K, which is 0.08 higher than that of un-doped β-Zn4Sb3 at the corresponding temperature. Physical property experiments indicate that there is a potentiality for the improvement of thermoelectric properties if a proper elemental doping is carried out into the Zn-Sb based alloys, which was confirmed by AI addition in the present work.

  15. Corrosion and mechanical properties of hot-extruded AZ31 magnesium alloys

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    AZ31 magnesium alloys were hot-extruded at 573 K and 623 K with extrusion ratio (λ) of 20, 35 and 50. The corrosion and mechanical behavior of hot-extruded AZ31 were studied by galvanic tests and tensile tests. The microstructures of the studied AZ31 alloys were also investigated with optical microscope. The results show that, compared with the as-cast AZ31 alloy, the corrosion potentials of all hot-extruded AZ31 alloys are increased by 60 mV. Moreover, at the extrusion temperature of 623 K, the galvanic current of AZ31 alloy decreases with increasing extrusion and the galvanic corrosion resistance is increased by 10% with the extrusion ratio of 50. In addition, the tensile strength and elongation of the extruded alloys are significantly enhanced by about 20% and 140%, respectively. The improvement of corrosion resistance and obvious increasing of mechanical properties of AZ31 alloys by hot-extrusion are ascribed to grain refinement and microstructural modification together with the homogeneous distribution of intermetallie phases throughout the matrix.

  16. Thermal Exposure Effects on Properties of Al-Li Alloy Plate Products

    Science.gov (United States)

    Shah, Sandeep; Wells, Douglas; Wagner, John; Babel, Henry

    2002-01-01

    Aluminum-Lithium (AL-Li) alloys offer significant performance benefits for aerospace structural applications due to their higher specific properties compared with conventional aluminum alloys. For example, the application of an Al-Li alloy to the space shuttle external cryogenic fuel tank contributed to the weight savings that enabled successful deployment of International Space Station components. The composition and heat treatment of this alloy were optimized specifically for strength-toughness considerations for an expendable cryogenic tank. Time dependent properties related to reliability, such as thermal stability, fatigue, and corrosion, will be of significant interest when materials are evaluated for a reusable cryotank structure. As most aerospace structural hardware is weight sensitive, a reusable cryotank will be designed to the limits of the materials mechanical properties. Therefore, this effort was designed to establish the effects of thermal exposure on the mechanical properties and microstructure of one relatively production mature alloy and two developmental alloys C458 and L277. Tensile and fracture toughness behavior was evaluated after exposure to temperatures as high as 3oooF for up to IO00 hrs. Microstructural changes were also evaluated to correlate with the observed data trends. The ambient temperature parent metal data showed an increase in strength and reduction in elongation after exposure at lower temperatures. Strength reached a peak with intermediate temperature exposure followed by a decrease at highest exposure temperature. Characterizing the effect of thermal exposure on the properties of Al-Li alloys is important to defining a service limiting temperature, exposure time, and end-of-life properties.

  17. Microstructure and mechanical properties of rolled Mg-12Gd-3Y-0.4Zr alloy sheets

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The extruded Mg-12Gd-3Y-0.4Zr alloy sheets were rolled from 30 mm to 2.3 mm at 723 K by electric heated rollers, and then different heat treatments were performed to improve their properties. The microstructures and tensile properties of the alloy sheets were investigated, including as-rolled, annealed and T5 treated. The experimental results show that the grains are effectively refined by the rolling process, and the strength of the rolled alloy is greatly enhanced. The annealed alloy exhibits lower strength and higher elongation than the rolled one, while the aged alloy shows higher strength and lower elongation. After being aged at 498 K for 17 h, the alloys get the highest strength, namely, the ultimate tensile strength is 456.8 MPa, yield strength is 348.9 MPa, and elongation is 3.8%.

  18. Effect of gadolinium on aged hardening behavior,microstructure and mechanical properties of Mg-Nd-Zn-Zr alloy

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Mg-3.4Nd-0.1 Zn-0.40Zr alloy samples with and without containing gadolinium(0.6%,mass fraction)were prepared by sand casting.The aged hardening behavior,solidification microstructures and mechanical properties of the alloys were investigated by using the analysis methods of OM,XRD,TEM,hardness tests and mechanical property tests.The main research results are as follows.1)Compared with the alloy without the addition of gadolinium.the alloys with the addition of gadolinium shows the more remarkable age-hardening response.2) The as-cast microstructure of the alloy with and without containing gadolinium consists of α-Mg grains with Mg12Nd phase on the grain boundary.After solution heat-treatment,Mg12Nd phase of the alloy without containing gadolinium is dissolved in the matrix,however,there iS still discontinued Mg12Nd phase at grain boundary of the alloy with containing gadolinium.The more finely dispersed precipitates in Mg matrix are formed in the alloy with containing gadolinium during age-treatment.3)The room temperature and high temperature mechanical properties ofthe alloy are satisfactory.with σb=280 MPa,σ0.2=165 MPa at RT and aσb=215 MPa,σ0.2=155 MPa at 250℃.The high temperature mechanical properties decrease slightly with the increase of temperature.

  19. Swelling and tensile properties of neutron-irradiated vanadium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Loomis, B.A.; Smith, D.L.

    1990-07-01

    Vanadium-base alloys are candidates for use as structural material in magnetic fusion reactors. In comparison to other candidate structural materials (e.g., Type 316 stainless and HT-9 ferritic steels), vanadium-base alloys such as V-15Cr-5Ti and V-20Ti have intrinsically lower long-term neutron activation, neutron irradiation after-heat, biological hazard potential, and neutron-induced helium and hydrogen transmutation rates. Moreover, vanadium-base alloys can withstand a higher surface-heat, flux than steels because of their lower thermal stress factor. In addition to having these favorable neutronic and physical properties, a candidate alloy for use as structural material in a fusion reactor must have dimensional stability, i.e., swelling resistance, and resistance to embrittlement during the reactor lifetime at a level of structural strength commensurate with the reactor operating temperature and structural loads. In this paper, we present experimental results on the swelling and tensile properties of several vanadium-base alloys after irradiation at 420, 520, and 600{degree}C to neutron fluences ranging from 0.3 to 1.9 {times} 10{sup 27} neutrons/m{sup 2} (17 to 114 atom displacements per atom (dpa)).

  20. Microstructure and tensile properties of low cost titanium alloys at different cooling rate

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    Titanium and titanium alloys have several advantages, but the cost of titanium alloys is very expensive compared with the traditional metal materials. This article introduces two new low-cost titanium alloys Ti-2.1Cr-1.3Fe (TCF alloy) and Ti-3Al-2.1Cr-1.3Fe (TACF alloy). In this study, we used Cr-Fe master alloy as one of the raw materials to develop the two new alloys. We introduce the microstructure and tensile properties of the two new alloys from β solution treated with different cooling methods. Optica...

  1. Mechanical properties of titanium alloys with strengthened surface layers

    Directory of Open Access Journals (Sweden)

    I.M. Pohreliuk

    2011-12-01

    Full Text Available Influence of oxinitriding and boriding on the mechanical properties (ultimate strength to destruction at uniaxial tension, plasticity, tendency to delayed destruction, fatigue resistance at bending with rotation, fatigue life at lowcycle pure bending of titanium alloys is studied.

  2. Investigations of mechanically alloyed nanocrystalline materials by microacoustic techniques

    Science.gov (United States)

    Dubief, P.; Hunsinger, J. J.; Gaffet, E.

    1996-09-01

    The purpose of this work is to determine whether yes or no, there is a difference between the physico-chemical properties of the nanocrystalline and the microcrystalline materials. This paper deals with the acoustical behavior of nanocrystalline materials which were prepared by ball- milling and mechanical alloying. Based on two specific techniques (acoustic microinterferometry and acoustic microechography), some of the mechanical properties (elastic ones) may be determined, related to a materials volume of about a few micrometers 3 (for the high frequency 600 MHz apparatus). Thus the mechanically alloyed powders (typically 200 micrometers in diameter), behave as massive materials in this range of frequency. The measurements are directly obtained on the grains and do not take into account the voids induced by further sinthering process. The result of such a micromechanical approach will be given for pure ball-milled elements (Fe) and for the supersaturated solid phase Fe(Si) obtained by mechanical alloying.

  3. Properties of Co2FeAl Heusler Alloy Nano-particles Synthesized by Coprecipitation and Thermal Deoxidization Method

    Institute of Scientific and Technical Information of China (English)

    J.H.Du; Y.L.Zuo; Z.Wang; J.H.Ma; L.Xi

    2013-01-01

    Co2FeAl nanoparticles were synthesized by reducing the coprecipitated precursor of CoCl2·6H2O,Fe(NO3)3·9H2O and Al2(SO4)3·18H2O under H2 atmosphere with various annealing temperatures and durations.X-ray diffraction and transmission electron microscopy were used to characterize the crystal structure and microstructure of Co2FeAl particles,respectively.The investigation indicates that the crystal structure of Co2FeAl particles tends to be B2 structure,in which atoms are partially ordered.The saturation magnetization and hyperfine field of Co2FeAl particles,which were measured under a vibrating sample magnetometer and a 57Fe M(o)ssbauer spectroscope,are consistent with those of the bulk sample and thin films.Furthermore,the higher annealing temperature and the longer annealing time,the better crystallinity of Co2FeAl and more ordered arrangement of atoms will be.It turned out that the coprecipitation thermal deoxidization method could be an easy and high efficient way to obtain the half-metallic Co2FeAl nanoparticles.

  4. Effect of titanium content and aging temperature on the properties of uranium-titanium alloys

    International Nuclear Information System (INIS)

    The mechanical properties and microstructures of four uranium-titanium alloys were examined as functions of titanium content and aging temperature. Titanium alloy content was varied from 0.41 to 0.79 weight percent. Aging temperatures from 350 to 4500C (all for six hours) were evaluated for each alloy in addition to tests in the unaged conditions. Titanium and aging temperature were both shown to be strong effects in determining alloy properties. It was determined that the uranium-0.41 weight percent titanium alloy underwent extensive age-hardening even though the alloy did not exhibit a martensitic microstructure characteristic of the alloys richer in titanium

  5. Properties of Alloy 617 for Heat Exchanger Design

    Energy Technology Data Exchange (ETDEWEB)

    Wright, Richard Neil [Idaho National Laboratory; Carroll, Laura Jill [Idaho National Laboratory; Benz, Julian Karl [Idaho National Laboratory; Wright, Julie Knibloe [Idaho National Laboratory; Lillo, Thomas Martin [Idaho National Laboratory; Lybeck, Nancy Jean [Idaho National Laboratory

    2014-10-01

    Abstract – Alloy 617 is among the primary candidates for very high temperature reactor heat exchangers anticipated for use up to 950ºC. Elevated temperature properties of this alloy and the mechanisms responsible for the observed tensile, creep and creep-fatigue behavior have been characterized over a wide range of test temperatures up to 1000ºC. Properties from the current experimental program have been combined with archival information from previous VHTR research to provide large data sets for many heats of material, product forms, and weldments. The combined data have been analyzed to determine conservative values of yield and tensile strength, strain rate sensitivity, creep-rupture behavior, fatigue and creep- fatigue properties that can be used for engineering design of reactor components. Phenomenological models have been developed to bound the regions over which the engineering properties are well known or can be confidently extrapolated for use in design.

  6. Enhancement of wear and corrosion resistance of beta titanium alloy by laser gas alloying with nitrogen

    Science.gov (United States)

    Chan, Chi-Wai; Lee, Seunghwan; Smith, Graham; Sarri, Gianluca; Ng, Chi-Ho; Sharba, Ahmed; Man, Hau-Chung

    2016-03-01

    The relatively high elastic modulus coupled with the presence of toxic vanadium (V) in Ti6Al4V alloy has long been a concern in orthopaedic applications. To solve the problem, a variety of non-toxic and low modulus beta-titanium (beta-Ti) alloys have been developed. Among the beta-Ti alloy family, the quaternary Ti-Nb-Zr-Ta (TNZT) alloys have received the highest attention as a promising replacement for Ti6Al4V due to their lower elastic modulus and outstanding long term stability against corrosion in biological environments. However, the inferior wear resistance of TNZT is still a problem that must be resolved before commercialising in the orthopaedic market. In this work, a newly developed laser surface treatment technique was employed to improve the surface properties of Ti-35.3Nb-7.3Zr-5.7Ta alloy. The surface structure and composition of the laser-treated TNZT surface were examined by grazing incidence X-ray diffraction (GI-XRD) and X-ray photoelectron spectroscopy (XPS). The wear and corrosion resistance were evaluated by pin-on-plate sliding test and anodic polarisation test in Hanks' solution. The experimental results were compared with the untreated (or base) TNZT material. The research findings showed that the laser surface treatment technique reported in this work can effectively improve the wear and corrosion resistance of TNZT.

  7. Microstructures and Properties of W-Ti Alloys Prepared Under Different Cooling Conditions

    Science.gov (United States)

    Dai, Weili; Liang, Shuhua; Yang, Qing; Zou, Juntao; Zhuo, Longchao

    2016-07-01

    W-(10 to 15) wt.% Ti alloys were sintered at 1400 or 1500 °C and cooled under different cooling conditions. The microstructures and properties of W-Ti alloys were affected by the cooling conditions. XRD, SEM, EBSD, and TEM were carried out to investigate the effects of cooling conditions and sintering temperature on the microstructures of W-Ti alloys. The nanohardness and elastic modulus of the alloys were also investigated. The results showed that when the temperature was 1500 °C, the content of Ti-rich phase in W-(10 to 15) wt.% Ti alloys decreased obviously with the increase of cooling rate (the average cooling rate of furnace cooling, air cooling and water cooling was 0.2, 10, and 280 °C/s, respectively). For the W-10 wt.% Ti alloy, the content decreased from 20.5 to 9.7%, and the grain size decreased from 2.33 to 0.67 μm. When the temperature decreased to 1400 °C, the grain size was also decreased sharply with the increase of cooling rate, but there was a little change in the microstructure. Meanwhile, the grain sizes were smaller than those of the alloys sintered at 1500 °C. The nanohardness and elastic modulus increased with the increase of cooling rate, and the alloys sintered at different temperatures had different nanohardness and elastic modulus which depended on the cooling conditions. Sintering at a proper temperature and then cooling at a certain cooling condition was a useful method to fabricate alloy with less Ti-rich phase and high properties.

  8. Tensile properties of V-Cr-Ti alloys after exposure in hydrogen-containing environments

    Energy Technology Data Exchange (ETDEWEB)

    Natesan, K.; Soppet, W.K. [Argonne National Lab., IL (United States)

    1998-09-01

    A systematic study has been initiated at Argonne National Laboratory to evaluate the performance of several V-Cr-Ti alloys after exposure to environments containing hydrogen at various partial pressures. The goal is to correlate the chemistry of the exposure environment with hydrogen uptake in the samples and its influence on the microstructure and tensile properties of the alloys. At present, the principal effort has focused on the V-4Cr-4Ti alloy of heat identified as BL-71; however other alloys (V-5Cr-5Ti alloy of heats BL-63, and T87, plus V-4Cr-4Ti alloy from General Atomics [GA]) are also being evaluated. Other variables of interest are the effect of initial grain size on the tensile behavior of the alloys. Experiments conducted on specimens of various V-Cr-Ti alloys exposed to pH{sub 2} levels of 0.01 and 3 {times} 10{sup {minus}6} torr showed negligible effect of H{sub 2} on either maximum engineering stress or uniform and total elongation. However, uniform and total elongation decreased substantially when the alloys were exposed to 1.0 torr H{sub 2} pressure. Preliminary data from sequential exposures of the materials to low-pO{sub 2} and several low-pH{sub 2} environments did not reveal an adverse effect on the maximum engineering stress or on uniform and total elongation. Further, tests in H{sub 2} environments on specimens annealed at different temperatures showed that grain-size variation by a factor of {approx}2 had little or no effect on tensile properties.

  9. Mechanical properties and corrosion resistance of hot extruded Mg–2.5Zn–1Ca alloy

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Dexue, E-mail: dexeliu@hotmail.com [State Key Laboratory of Advanced Processing and Recycling of Non-Ferrous Metals, Lanzhou University of Technology, Lanzhou 730050 (China); Department of Mechanical and Aerospace Engineering, University of California, San Diego, CA 92093-0411 (United States); Guo, Chenggong; Chai, Liqiang [State Key Laboratory of Advanced Processing and Recycling of Non-Ferrous Metals, Lanzhou University of Technology, Lanzhou 730050 (China); Sherman, Vincent R. [Department of Mechanical and Aerospace Engineering, University of California, San Diego, CA 92093-0411 (United States); Qin, Xiaoqiong; Ding, Yutian [State Key Laboratory of Advanced Processing and Recycling of Non-Ferrous Metals, Lanzhou University of Technology, Lanzhou 730050 (China); Meyers, Marc A. [Department of Mechanical and Aerospace Engineering, University of California, San Diego, CA 92093-0411 (United States)

    2015-05-15

    Highlights: • MgZnCa alloy was extruded into precise microtube for resorbable stent applications. • Interconnection between micro-structure and corrosion properties was revealed. • Both strength and ductility were simultaneously improved by processing sequence. • Better corrosion resistance in PBS solution was achieved after grain refining. - Abstract: It is demonstrated that the mechanical properties and corrosion resistance of Mg–2.5 wt%Zn–1 wt%Ca alloy are enhanced by the microstructural changes imparted by hot extrusion. A processing procedure is developed to form hollow tubes with an outer diameter of ∼2.0 mm and wall thickness of ∼0.1 mm, which is well suited for subsequent stent manufacturing. The influence of thermal and mechanical processing on corrosion and plasticity was found to be associated with grain-size reduction and the redistribution of intermetallic particles within the microstructure, providing significant improvement of performance over the cast alloy. Observation of the fracture surfaces reveals a mode transition from brittle (cast) to ductile (processed). Enhanced mechanical properties and decreased resorption rate represent significantly improved performance of this alloy after the novel processing sequence. Based on the improved properties, the produced Mg alloy is more suitable for practical in vivo applications.

  10. Microstructure and mechanical properties of eutectic nickel alloy coatings

    Science.gov (United States)

    Bezborodov, V. P.; Saraev, Yu N.

    2016-04-01

    The paper discusses the peculiarities of a structure and a coating composition after reflow. It was established that the structure of coatings from nickel alloy is a solid solution based on nickel, the eutectic of γ-Ni+Ni3B composition and dispersed reinforcing particles. The content of alloying elements in the initial powder material determines the type of the coating structure and the formation of hypoeutectic or hypereutectic structures. The influence of formation conditions on the structure and physical-mechanical properties of the coatings is considered in this paper.

  11. Directional Solidification and Mechanical Properties of NiAl-NiAlTa Alloys

    Science.gov (United States)

    Johnson, D. R.; Chen, X. F.; Oliver, B. F.; Noebe, R. D.; Whittenberger, J. D.

    1995-01-01

    Directional solidification of eutectic alloys is a promising technique for producing in-situ composite materials exhibiting a balance of properties. Consequently, the microstructure, creep strength and fracture toughness of directionally solidified NiAl-NiAlTa alloys were investigated. Directional solidification was performed by containerless processing techniques to minimize alloy contamination. The eutectic composition was found to be NiAl-15.5 at% Ta and well-aligned microstructures were produced at this composition. A near-eutectic alloy of NiAl-14.5Ta was also investigated. Directional solidification of the near-eutectic composition resulted in microstructures consisting of NiAl dendrites surrounded by aligned eutectic regions. The off-eutectic alloy exhibited promising compressive creep strengths compared to other NiAl-based intermetallics, while preliminary testing indicated that the eutectic alloy was competitive with Ni-base single crystal superalloys. The room temperature toughness of these two-phase alloys was similar to that of polycrystalline NiAl even with the presence of the brittle Laves phase NiAlTa.

  12. Tensile and creep properties of thermomechanically processed boron modified Timetal 834 titanium alloy

    International Nuclear Information System (INIS)

    Highlights: → 0.2 wt.% boron refines the as-cast microstructure of Timetal 834 alloy. → The boron addition leads to an improvement in strength (0.2% YS and UTS). → The B modified alloy shows better creep resistance as compared to base alloy. → These effects are attributed to load sharing mechanism by the TiB whiskers. - Abstract: The effect of addition of 0.2 wt.% B on the tensile and creep properties of Timetal 834 alloy was studied in the thermomechanically processed condition after subjecting it to different heat treatments. The 0.2% YS and UTS of the boron modified alloy was found to be higher than that of the base alloy irrespective of the heat treatment employed. The creep strain for 100 h as well as the steady state creep rate at a temperature of 600 deg. C and initial stress of 150 MPa stress was also significantly lower for the B modified alloy. The results were explained on the basis of load sharing by the TiB whiskers.

  13. Effects of thermal treatments on microstructure and mechanical properties of a Co-Cr-Mo-W biomedical alloy produced by laser sintering.

    Science.gov (United States)

    Mengucci, P; Barucca, G; Gatto, A; Bassoli, E; Denti, L; Fiori, F; Girardin, E; Bastianoni, P; Rutkowski, B; Czyrska-Filemonowicz, A

    2016-07-01

    Direct Metal Laser Sintering (DMLS) technology based on a layer by layer production process was used to produce a Co-Cr-Mo-W alloy specifically developed for biomedical applications. The alloy mechanical response and microstructure were investigated in the as-sintered state and after post-production thermal treatments. Roughness and hardness measurements, and tensile and flexural tests were performed to study the mechanical response of the alloy while X-ray diffraction (XRD), electron microscopy (SEM, TEM, STEM) techniques and microanalysis (EDX) were used to investigate the microstructure in different conditions. Results showed an intricate network of ε-Co (hcp) lamellae in the γ-Co (fcc) matrix responsible of the high UTS and hardness values in the as-sintered state. Thermal treatments increase volume fraction of the ε-Co (hcp) martensite but slightly modify the average size of the lamellar structure. Nevertheless, thermal treatments are capable of producing a sensible increase in UTS and hardness and a strong reduction in ductility. These latter effects were mainly attributed to the massive precipitation of an hcp Co3(Mo,W)2Si phase and the contemporary formation of Si-rich inclusions. PMID:26803005

  14. Influence of Cobalt on the Properties of Load-Sensitive Magnesium Alloys

    Directory of Open Access Journals (Sweden)

    Kai Kerber

    2012-12-01

    Full Text Available In this study, magnesium is alloyed with varying amounts of the ferromagnetic alloying element cobalt in order to obtain lightweight load-sensitive materials with sensory properties which allow an online-monitoring of mechanical forces applied to components made from Mg-Co alloys. An optimized casting process with the use of extruded Mg-Co powder rods is utilized which enables the production of magnetic magnesium alloys with a reproducible Co concentration. The efficiency of the casting process is confirmed by SEM analyses. Microstructures and Co-rich precipitations of various Mg-Co alloys are investigated by means of EDS and XRD analyses. The Mg-Co alloys’ mechanical strengths are determined by tensile tests. Magnetic properties of the Mg-Co sensor alloys depending on the cobalt content and the acting mechanical load are measured utilizing the harmonic analysis of eddy-current signals. Within the scope of this work, the influence of the element cobalt on magnesium is investigated in detail and an optimal cobalt concentration is defined based on the performed examinations.

  15. Microstructure and Thermomechanical Properties of Magnesium Alloys Castings

    Directory of Open Access Journals (Sweden)

    P. Lichý

    2012-04-01

    Full Text Available Magnesium alloys thanks to their high specific strength have an extensive potential of the use in a number of industrial applications. The most important of them is the automobile industry in particular. Here it is possible to use this group of materials for great numbers of parts from elements in the car interior (steering wheels, seats, etc., through exterior parts (wheels particularly of sporting models, up to driving (engine blocks and gearbox mechanisms themselves. But the use of these alloys in the engine structure has its limitations as these parts are highly thermally stressed. But the commonly used magnesium alloys show rather fast decrease of strength properties with growing temperature of stressing them. This work is aimed at studying this properties both of alloys commonly used (of the Mg-Al-Zn, Mn type, and of that ones used in industrial manufacture in a limited extent (Mg-Al-Sr. These thermomechanical properties are further on complemented with the microstructure analysis with the aim of checking the metallurgical interventions (an effect of inoculation. From the studied materials the test castings were made from which the test bars for the tensile test were subsequently prepared. This test took place within the temperature range of 20°C – 300°C. Achieved results are summarized in the concluding part of the contribution.

  16. Microstructure evolution and mechanical properties of a Ti-35Nb-3Zr-2Ta biomedical alloy processed by equal channel angular pressing (ECAP).

    Science.gov (United States)

    Lin, Zhengjie; Wang, Liqiang; Xue, Xiaobing; Lu, Weijie; Qin, Jining; Zhang, Di

    2013-12-01

    In this paper, an equal channel angular pressing method is employed to refine grains and enhance mechanical properties of a new β Ti-35Nb-3Zr-2Ta biomedical alloy. After the 4th pass, the ultrafine equiaxed grains of approximately 300 nm and 600 nm are obtained at pressing temperatures of 500 and 600°C respectively. The SEM images of billets pressed at 500°C reveal the evolution of shear bands and finally at the 4th pass intersectant networks of shear bands, involving initial band propagation and new band broadening, are formed with the purpose of accommodating large plastic strain. Furthermore, a unique herringbone microstructure of twinned martensitic variants is observed in TEM images. The results of microhardness measurements and uniaxial tensile tests show a significant improvement in microhardness and tensile strength from 534 MPa to 765 MPa, while keeping a good level of ductility (~16%) and low elastic modulus (~59 GPa). The maximum superelastic strain of 1.4% and maximum recovered strain of 2.7% are obtained in the billets pressed at 500°C via the 4th pass, which exhibits an excellent superelastic behavior. Meanwhile, the effects of different accumulative deformations and pressing temperatures on superelasticity of the ECAP-processed alloys are investigated. PMID:24094159

  17. Novel pre-alloyed powder processing of modified alnico 8: Correlation of microstructure and magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, I. E., E-mail: andersoni@ameslab.gov; Kassen, A. G.; White, E. M. H.; Zhou, L.; Tang, W.; Palasyuk, A.; Dennis, K. W.; McCallum, R. W.; Kramer, M. J. [Ames Laboratory (USDOE), Iowa State University, Ames, Iowa 50011 (United States)

    2015-05-07

    Progress is reviewed on development of an improved near-final bulk magnet fabrication process for alnico 8, as a non-rare earth permanent magnet with promise for sufficient energy density and coercivity for electric drive motors. This study showed that alnico bulk magnets in near-final shape can be made by simple compression molding from spherical high purity gas atomized pre-alloyed powder. Dwell time at peak sintering temperature (1250 °C) greatly affected grain size of the resulting magnet alloys. This microstructure transformation was demonstrated to be useful for gaining partially aligned magnetic properties and boosting energy product. While a route to increased coercivity was not identified by these experiments, manufacturability of bulk alnico magnet alloys in near-final shapes was demonstrated, permitting further processing and alloy modification experiments that can target higher coercivity and better control of grain anisotropy during grain growth.

  18. Microstructure and mechanical properties of Ti-15Zr alloy used as dental implant material.

    Science.gov (United States)

    Medvedev, Alexander E; Molotnikov, Andrey; Lapovok, Rimma; Zeller, Rolf; Berner, Simon; Habersetzer, Philippe; Dalla Torre, Florian

    2016-09-01

    Ti-Zr alloys have recently started to receive a considerable amount of attention as promising materials for dental applications. This work compares mechanical properties of a new Ti-15Zr alloy to those of commercially pure titanium Grade4 in two surface conditions - machined and modified by sand-blasting and etching (SLA). As a result of significantly smaller grain size in the initial condition (1-2µm), the strength of Ti-15Zr alloy was found to be 10-15% higher than that of Grade4 titanium without reduction in the tensile elongation or compromising the fracture toughness. The fatigue endurance limit of the alloy was increased by around 30% (560MPa vs. 435MPa and 500MPa vs. 380MPa for machined and SLA-treated surfaces, respectively). Additional implant fatigue tests showed enhanced fatigue performance of Ti-15Zr over Ti-Grade4. PMID:27258932

  19. Structural and Thermoelectric Properties of Ternary Full-Heusler Alloys

    Science.gov (United States)

    Hayashi, K.; Eguchi, M.; Miyazaki, Y.

    2016-09-01

    The thermoelectric properties of ternary full-Heusler alloys, Co2 YZ, which are in a ferromagnetic state up to high temperature above 300 K, were measured and are discussed in terms of the crystal structure and electronic states. Among the full-Heusler alloys studied, the Co2MnSi sample exhibited the highest absolute value of Seebeck coefficient and also the highest electrical conductivity in the temperature range from 300 K to 1023 K. The highest power factor of 2.9 × 10-3 W/m-K2 was obtained for the Co2MnSi sample at 550 K, demonstrating the potential of half-metallic full-Heusler alloys as thermoelectric materials.

  20. Microstructure and properties of Mg-Al binary alloys

    Institute of Scientific and Technical Information of China (English)

    ZHENG Wei-chao; LI Shuang-shou; TANG Bin; ZENG Da-ben

    2006-01-01

    The effects of different amounts of added Al, ranging from 1% to 9%, on the microstructure and properties of Mg-Al binary alloys were investigated. The results showed that when the amount of added Al is less than 5%, the grain size of the Mg-Al binary alloys decreases dramatically from 3 097 μm to 151 μm with increasing addition of Al. Further addition of Al up to 9% makes the grain size decrease slowly to 111 μm. The α-Mg dendrite arms are also refined. Increasing the amount of added Al decreases the hot cracking susceptibility of the Mg-Al binary alloys remarkably, and enhances the micro-hardness of the α-Mg matrix.

  1. Microstructure and properties of Mg-Al binary alloys

    Directory of Open Access Journals (Sweden)

    ZHENG Wei-chao

    2006-11-01

    Full Text Available The effects of different amounts of added Al, ranging from 1 % to 9 %, on the microstructure and properties of Mg-Al binary alloys were investigated. The results showed that when the amount of added Al is less than 5%, the grain size of the Mg-Al binary alloys decreases dramatically from 3 097 μm to 151 μm with increasing addition of Al. Further addition of Al up to 9% makes the grain size decrease slowly to 111 μm. The α-Mg dendrite arms are also refined. Increasing the amount of added Al decreases the hot cracking susceptibility of the Mg-Al binary alloys remarkably, and enhances the micro-hardness of the α-Mg matrix.

  2. Microstructure and properties of hot extruded AZ31-0.25%Sb Mg-alloy

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The effects of hot extrusion treatment on the microstructure and mechanical properties of AZ31-0.25%Sb Mg alloy were mvestlgated by means of mechanical properties measurement and microstructure observation.The results show that the (UTS) and yield tensile strength(YTS) of the alloy are obviously enhanced by hot extrusion treatment,and the enhanced extent of UTS and YTS increases with the decrease of hot extrusion temperature,moreover,the YTS value of the alloy at RT,after extruded at 220℃,increases up to 131.4%,which attributes to the finer grains resulted from the dynamic recrystallization occurred during hot extrusion.As not extrusion goes on,the slipping and concentration of dislocations continue to occur within the finer grains,which promotes the formation of the subgrains in the alloy.The deformation features of the extruded alloy during tensile deformation at RT are the twinning deformation and dislocation slipping in the twinning regions.Moreover,the deformation mechanisms of the alloy are a dislocation activation on the basal plane and a+c dislocation activation on the pyramidal planes.

  3. The effect of phosphorus on the microstructure and mechanical properties of ATI 718Plus alloy

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Minqing, E-mail: minqingw@yahoo.com [Central Iron and Steel Research Institute, Beijing 100081 (China); School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Beijing Key Laboratory of Advanced High Temperature Materials, Beijing 100081 (China); Du, Jinhui; Deng, Qun [Central Iron and Steel Research Institute, Beijing 100081 (China); Beijing Key Laboratory of Advanced High Temperature Materials, Beijing 100081 (China); Tian, Zhiling [Central Iron and Steel Research Institute, Beijing 100081 (China); Zhu, Jing, E-mail: jzhu@mail.tsinghua.edu.cn [School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China)

    2015-02-25

    Since the discovery in the 1990s of the abnormal improvement produced by phosphorus in the stress rupture and creep life of Inconel 718 (hereafter referred to as 718), a great deal of additional research followed. However, the mechanism of the action of phosphorous in 718 is still in question. This paper details an experimental study that was intended to determine how phosphorus acts upon the microstructure and mechanical properties of Ni–Fe based alloy 718Plus. The results show that phosphorus has little effect on the strength and ductility of alloy 718Plus, but can significantly improve the stress rupture life. Phase constituents such as the δ and γ′ phases were quantitatively analyzed using electrolytic phase isolation and micro-chemical and XRD analysis as the phosphorous content of the alloy was increased. A full atom mapping of the distribution of phosphorus in the 718Plus alloy was quantitatively determined using APT (Atom Probe Tomography) technique. The results showed that there is no significant segregation of phosphorus at the γ′/γ and γ′/γ′ interface, but it significantly segregates at the grain boundaries and δ/γ interface. It was found that phosphorus is extremely depleted in the δ phase, which is believed to inhibit δ-phase precipitation by preventing δ phase nucleation and growth in the 718Plus alloy. Finally, the influence of phosphorus on the microstructure and mechanical properties of the 718Plus alloy was discussed.

  4. Nanoscale Electro Negative Interface Density (NENID) in magnesium alloy nanocomposites: Effect on mechanical properties

    International Nuclear Information System (INIS)

    In metal matrix composites, particle–matrix interfacial reactions are generally undesirable as this leads to poor interface formation where the particle–matrix stress transfer characteristics are inferior. This is of particular concern regarding magnesium alloy nanocomposites for wide ranging weight critical structural applications. In this study, various magnesium alloy nanocomposites containing Al2O3, carbon nanotube, TiC, or Si3N4 nanoparticle reinforcement were fabricated using solidification processing followed by hot extrusion. Here and for the first time, Nanoscale Electro Negative Interface Density (NENID) quantifies the nanoparticle–alloy matrix interfacial area per unit volume in the magnesium alloy nanocomposite taking into consideration the electronegativity of the nanoparticle reinforcement. We suggest that (1) NENID affects selected mechanical properties in magnesium alloy nanocomposites and (2) there are two joint mechanisms at nanoscale that enable tensile strength and ductility of the alloy nanocomposites to be simultaneously enhanced. We show that NENID indicates the possibility of relatively increased nanoparticle–alloy matrix interfacial reactions occurring while taking into account thermodynamic considerations.

  5. Nanoscale Electro Negative Interface Density (NENID) in magnesium alloy nanocomposites: Effect on mechanical properties

    Energy Technology Data Exchange (ETDEWEB)

    Paramsothy, M. [National University of Singapore, Department of Mechanical Engineering (Singapore); Chan, J.; Kwok, R. [Singapore Technologies Kinetics Ltd (ST Kinetics) (Singapore); Gupta, M., E-mail: mpegm@nus.edu.sg [National University of Singapore, Department of Mechanical Engineering (Singapore)

    2012-06-15

    In metal matrix composites, particle-matrix interfacial reactions are generally undesirable as this leads to poor interface formation where the particle-matrix stress transfer characteristics are inferior. This is of particular concern regarding magnesium alloy nanocomposites for wide ranging weight critical structural applications. In this study, various magnesium alloy nanocomposites containing Al{sub 2}O{sub 3}, carbon nanotube, TiC, or Si{sub 3}N{sub 4} nanoparticle reinforcement were fabricated using solidification processing followed by hot extrusion. Here and for the first time, Nanoscale Electro Negative Interface Density (NENID) quantifies the nanoparticle-alloy matrix interfacial area per unit volume in the magnesium alloy nanocomposite taking into consideration the electronegativity of the nanoparticle reinforcement. We suggest that (1) NENID affects selected mechanical properties in magnesium alloy nanocomposites and (2) there are two joint mechanisms at nanoscale that enable tensile strength and ductility of the alloy nanocomposites to be simultaneously enhanced. We show that NENID indicates the possibility of relatively increased nanoparticle-alloy matrix interfacial reactions occurring while taking into account thermodynamic considerations.

  6. Fabrication, magnetostriction properties and applications of Tb-Dy-Fe alloys: a review

    Directory of Open Access Journals (Sweden)

    Nai-juan Wang

    2016-03-01

    Full Text Available As an excellent giant-magnetostrictive material, Tb-Dy-Fe alloys (based on Tb0.27-0.30Dy0.73-0.70Fe1.9-2 Laves compound can be applied in many engineering fields, such as sonar transducer systems, sensors, and micro-actuators. However, the cost of the rare earth elements Tb and Dy is too high to be widely applied for the materials. Nowadays, there are two different ways to substitute for these alloying elements. One is to partially replace Tb or Dy by cheaper rare earth elements, such as Pr, Nd, Sm and Ho; and the other is to use non-rare earth elements, such as Co, Al, Mn, Si, Ce, B, Be and C, to substitute Fe to form single MgCu2-type Laves phase and a certain amount of Re-rich phase, which can reduce the brittleness and improve the corrosion resistance of the alloy. This paper systemically introduces the development, the fabrication methods and the corresponding preferred growth directions of Tb-Dy-Fe alloys. In addition, the effects of alloying elements and heat treatment on magnetostrictive and mechanical properties of Tb-Dy-Fe alloys are also reviewed, respectively. Finally, some possible applications of Tb-Dy-Fe alloys are presented.

  7. Effects of grain refinement on mechanical properties and microstructures of AZ31 alloy

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Cerium was added in AZ31 alloy with the contents of 0.4%, 0.8% and 1.2% respectively to produce experimental alloys.The grain refinement of Ce in the as-east and rolled AZ31 alloy were studied by using Polyvar-MET optical microscope with a VSM2000 quantitative analysis system, KYKY2000 SEM and Tecnai G2 20 TEM. And the mechanical properties of AZ31+Ce alloy were tested on a CSS-44100 testing system with computerized data acquisition. The results show that the cerium has a good grain refinement effect on the as-cast AZ31 alloy because cerium can build up a solute enriched zone rapidly during the solidification process. The dynamic recrystallization (DRX) grains less than 10 μm can be obtained in hot rolled AZ31+Ce alloy. A cold rolling deformation degree over than 20% and a following annealing at 400 ℃ for 1h will lead to refine and uniform grains with the sizes of about 25μm. The cerium can form dispersed and thermally stable Al4Ce phase that can prohibit the coarsening of grains in AZ31 +Ce alloy during the hot rolling and annealing process.

  8. Crystallization kinetics and magnetic properties of FeSiCr amorphous alloy powder cores

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Hu-ping [School of Logistics Engineering, Wuhan University of Technology, Wuhan 430063 (China); Wang, Ru-wu, E-mail: ruwuwang@hotmail.com [National Engineering Research Center For Silicon Steel, Wuhan 430080 (China); College of Materials Science and Metallurgical Engineering, Wuhan University of Science and Technology, Wuhan 430081 (China); Wei, Ding [School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074 (China); Zeng, Chun [National Engineering Research Center For Silicon Steel, Wuhan 430080 (China)

    2015-07-01

    The crystallization kinetics of FeSiCr amorphous alloy, characterized by the crystallization activation energy, Avrami exponent and frequency factor, was studied by non-isothermal differential scanning calorimetric (DSC) measurements. The crystallization activation energy and frequency factor of amorphous alloy calculated from Augis–Bennett model were 476 kJ/mol and 5.5×10{sup 18} s{sup −1}, respectively. The Avrami exponent n was calculated to be 2.2 from the Johnson–Mehl–Avrami (JMA) equation. Toroid-shaped Fe-base amorphous powder cores were prepared from the commercial FeSiCr amorphous alloy powder and subsequent cold pressing using binder and insulation. The characteristics of FeSiCr amorphous alloy powder and the effects of compaction pressure and insulation content on the magnetic properties, i.e., effective permeability μ{sub e}, quality factor Q and DC-bias properties of FeSiCr amorphous alloy powder cores, were investigated. The FeSiCr amorphous alloy powder cores exhibit a high value of quality factor and a stable permeability in the frequency range up to 1 MHz, showing superior DC-bias properties with a “percent permeability” of more than 82% at H=100 Oe. - Highlights: • The crystallization kinetics of FeSiCr amorphous alloy was investigated. • The FeSiCr powder cores exhibit a high value of Q and a stable permeability. • The FeSiCr powder cores exhibit superior DC-bias properties.

  9. Microstructure and mechanical properties of high strength as-cast Ti-15-3 alloy

    Institute of Scientific and Technical Information of China (English)

    丁宏升; 周建中; 贾均; 郭景杰; 苏彦庆; 傅恒志

    2002-01-01

    The effects of heat treatment and solidification cooling rate on the microstructure and mechanical properties of as-cast Ti-15-3 alloy prepared by induction skull melting method were investigated. Results show that the microstructure of as-cast Ti-15-3 alloy changes from the features of simplified and larger size of beta grains to finer grain size with increasing solidification cooling rate. After solution treatment and different ageing treatment, alpha phase precipitates in grains interior as well as in grain boundaries. Due to the modification of the precipitate phase, the tensile strength and elongation of the alloy are improved simultaneously. A good combination of the values of 1.406GPa of σb and 4.5% of δ was obtained, which will be satisfied the use of this kind of alloy in critical areas.

  10. Magnetic properties and magnetic exchange interactions in Gd1-xREx(RE=Pr, Nd) alloys

    Institute of Scientific and Technical Information of China (English)

    肖素芬; 陈云贵

    2016-01-01

    The effect of Pr, Nd addition on the magnetic properties and magnetic exchange interaction of gadolinium alloys was sys-tematically studied. Curie temperatureTC and magnetic moment of Gd1–xREx (RE=Pr, Nd) systems withx<0.05 were investigated. Whenx<0.05, Pr and Nd formed respectively with Gd continuous solid solution which has the crystalline structure HCP. Study on the magnetic behavior indicated that at near room temperature, the simple ferromagnetism prevailed in these two systems of alloy. The Curie temperature and magnetic moment of Gd1–xREx alloy decreased with RE (RE= Pr, Nd) contentx increasing. The de Gennes factor of Gd1–xREx alloy which was associated with the exchange interaction between magnetic spin components also decreased with RE content increasing. The above results showed that the magnetic exchange interaction between magnetic atoms in gadolinium could be effectively changed by the Pr, Nd addition.

  11. Effects of Ca addition on microstructure and properties of AZ63 magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    钱宝光; 耿浩然; 陶珍东; 赵鹏; 田宪法

    2004-01-01

    Effects of Ca addition on the microstructure and viscosity as well as electrochemical properties of casting AZ63 magnesium alloy were studied. Testing results show that the viscosity value increases with the increase of calcium content, especially at the higher temperature, and there exists such a relation between the ignition temperature and viscosity of magnesium alloy: when the melt viscosity increases, the ignition temperature increases too. The microstructure of AZ63 magnesium alloy is first refined and then coarsened with the increase of Ca addition. By the addition of 0.15% Ca, AZ63 alloy has more negative open-circuit potential(1. 624 5V), bigger anode efficiency (55.65%) and lower corrosion rate(0.214g/(m2·h).AZ63 allo6y containing some Ca content is a high driving-potential and high-efficiency sacrificial anodes material.

  12. Influence of solution treatment on microstructure, mechanical and corrosion properties of Mg-4Zn alloy

    Directory of Open Access Journals (Sweden)

    Hongmin Jia

    2015-09-01

    Full Text Available The solution treatment parameters, mechanical properties and corrosion behavior of binary Mg-4Zn alloy were investigated. The results showed that after the solution treatment at 335 °C for 16 h, Mg-4Zn alloy had an ultimate tensile strength of 184.13 MPa and elongation of 9.43%. Furthermore, the corrosion resistance was evaluated by electrochemical measurements and immersion tests in 3.5% NaCl solution. The results revealed that the corrosion current density of the solution treatment Mg alloy was 11.2 µA/cm−2, it was lower than 15.8 µA/cm−2 for the as-cast Mg alloy under the same conditions, which was greatly associated with the micro-cathode effect of the second phases.

  13. First-principles calculations atomic structure and elastic properties of Ti-Nb alloys

    CERN Document Server

    Timoshevskii, A N; Ivasishin, O M

    2011-01-01

    Elastic properties of Ti based \\beta-alloy were studied by the method of the model structure first principle calculations. Concentrational dependence of Young modulus for the binary \\beta-alloy Ti-Nb was discovered. It is shown that peculiarities visible at 15-18% concentrations can be related to the different Nb atoms distribution. Detailed comparison of the calculation results with the measurement results was done. Young modulus for the set of the ordered structures with different Nb atoms location, which simulate triple \\beta-alloys Ti-29.7%Zr-18.5%Nb and Ti-51.8%Zr-18.5%Nb have been calculated. The results of these calculations allowed us to suggest the concentration region for single-phase ternary \\beta-phase alloys possessing low values of Young's modulus.

  14. Biocorrosion properties of antibacterial Ti-10Cu sintered alloy in several simulated biological solutions.

    Science.gov (United States)

    Liu, Cong; Zhang, Erlin

    2015-03-01

    Ti-10Cu sintered alloy has shown strong antibacterial properties against S. aureus and E. coli and good cell biocompatibility, which displays potential application in dental application. The corrosion behaviors of the alloy in five different simulated biological solutions have been investigated by electrochemical technology, surface observation, roughness measurement and immersion test. Five different simulated solutions were chosen to simulate oral condition, oral condition with F(-) ion, human body fluids with different pH values and blood system. It has been shown that Ti-10Cu alloy exhibits high corrosion rate in Saliva pH 3.5 solution and Saliva pH 6.8 + 0.2F solution but low corrosion rate in Hank's, Tyrode's and Saliva pH 6.8 solutions. The corrosion rate of Ti-10Cu alloy was in a order of Hank's, Tyrode's, Saliva pH 6.8, Saliva-pH 3.5 and Saliva pH 6.8 + 0.2F from slow to fast. All results indicated acid and F(-) containing conditions prompt the corrosion reaction of Ti-Cu alloy. It was suggested that the Cu ion release in the biological environments, especially in the acid and F(-) containing condition would lead to high antibacterial properties without any cell toxicity, displaying wide potential application of this alloy.

  15. Effect of rhenium on the structure and properties of the weld metal of a molybdenum alloy

    Science.gov (United States)

    Dyachenko, V. V.; Morozov, B. P.; Tylkina, M. A.; Savitskiy, Y. M.; Nikishanov, V. V.

    1984-01-01

    The structure and properties of welds made in molybdenum alloy VM-1 as a function of rhenium concentrations in the weld metal were studied. Rhenium was introduced into the weld using rhenium wire and tape or wires of Mo-47Re and Mo-52Re alloys. The properties of the weld metal were studied by means of metallographic techniques, electron microscopy, X-ray analysis, and autoradiography. The plasticity of the weld metal sharply was found to increase with increasing concentration of rhenium up to 50%. During welding, a decarburization process was observed which was more pronounced at higher concentrations of rhenium.

  16. Morphology and Magnetic Properties of Electrodeposited Iron and Nickel Based Alloy Foils

    Institute of Scientific and Technical Information of China (English)

    GUO Zhan-cheng; LIU Mei-feng; SUN Chun-wen; LIU Yu-xing; LU Wei-chang

    2004-01-01

    An alternative to conventional process for the preparation of soft magnetic metal foils of Fe, Fe-Ni, Fe-Co and Fe-Ni-Co by electroforming was described. The microstructure and magnetic properties were observed. The results showed that the crystal size of the iron-based alloy foil is less than 10 μm, while that of nickel-based alloy foil is about 2 μm. Moreover, the electroformed Fe-Ni foil has better magnetic properties than the conventional milled permalloy 1J79 foil.

  17. Superior metallic alloys through rapid solidification processing (RSP) by design

    Energy Technology Data Exchange (ETDEWEB)

    Flinn, J.E. [Idaho National Engineering Laboratory, Idaho Falls, ID (United States)

    1995-05-01

    Rapid solidification processing using powder atomization methods and the control of minor elements such as oxygen, nitrogen, and carbon can provide metallic alloys with superior properties and performance compared to conventionally processing alloys. Previous studies on nickel- and iron-base superalloys have provided the baseline information to properly couple RSP with alloy composition, and, therefore, enable alloys to be designed for performance improvements. The RSP approach produces powders, which need to be consolidated into suitable monolithic forms. This normally involves canning, consolidation, and decanning of the powders. Canning/decanning is expensive and raises the fabrication cost significantly above that of conventional, ingot metallurgy production methods. The cost differential can be offset by the superior performance of the RSP metallic alloys. However, without the performance database, it is difficult to convince potential users to adopt the RSP approach. Spray casting of the atomized molten droplets into suitable preforms for subsequent fabrication can be cost competitive with conventional processing. If the fine and stable microstructural features observed for the RSP approach are preserved during spray casing, a cost competitive product can be obtained that has superior properties and performance that cannot be obtained by conventional methods.

  18. Dynamic and quasi-static mechanical properties of iron-nickel alloy honeycomb

    Science.gov (United Stat