Sample records for heusler-type alloys co2mnz

  1. Density functional study of elastic and vibrational properties of the Heusler-type alloys Fe2VAl and Fe2VGa

    DEFF Research Database (Denmark)

    Kanchana, V.; Vaitheeswaran, G.; Ma, Yanming


    The structural and elastic properties as well as phonon-dispersion relations of the Heusler-type alloys Fe2VAl and Fe2VGa are computed using density functional and density-functional perturbation theory within the generalized-gradient approximation. The calculated equilibrium lattice constants...

  2. Magnetic transformation of Ni{sub 2}AlMn Heusler-type shape memory alloys

    Energy Technology Data Exchange (ETDEWEB)

    Gejima, F.; Sutou, Y.; Kainuma, R.; Ishida, K.


    It has recently been reported that the movement of twin (or variant) boundaries, induced by a magnetic field during the martensitic transformation, affects the magnetic properties and shape change in the ferromagnetic NiGaMn shape memory (SM) alloys. These observations suggest that the NiGaMn SM alloys with an L2{sub 1} (Ni{sub 2}GaMn: Heusler) structure have the potential for use as a new type of smart materials whose SM properties can be controlled not only by temperature and stress, but also by a magnetic field. Very recently, the present authors have detected that in the alloys with compositions near the stoichiometric Ni{sub 2}AlMn, the ferromagnetic L2{sub 1} phase appears on low-temperature aging and it transforms martensitically from B2 to 2M. This suggests that the NiAlMn Heusler alloys could also exhibit unique magnetic and SM properties similar to those of the NiGaMn alloys. It is the purpose of this article to report the results of investigations on the magnetic properties of the NiAlMn Heusler alloys.

  3. The influence of chemical disorder enhancement on the martensitic transformation of the Ni{sub 50}Mn{sub 36}Sn{sub 14} Heusler-type alloy

    Energy Technology Data Exchange (ETDEWEB)

    Passamani, E.C., E-mail: [Departamento de Fisica, Universidade Federal do Espirito Santo, 29075-910 Vitoria, ES (Brazil); Nascimento, V.P.; Larica, C.; Takeuchi, A.Y. [Departamento de Fisica, Universidade Federal do Espirito Santo, 29075-910 Vitoria, ES (Brazil); Alves, A.L.; Proveti, J.R. [Departamento de Ciencias Matematicas e Naturais, Universidade Federal do Espirito Santo, 29932-540, Sao Mateus, ES (Brazil); Pereira, M.C. [Instituto de Ciencia e Tecnologia, Universidade Federal dos Vales do Jequitinhonha e Mucuri (UFVJM), 39803-371 Teofilo Otoni, Minas Gerais (Brazil); Fabris, J.D. [Departamento de Quimica, UFVJM, 39100-000 Diamantina, Minas Gerais (Brazil)


    Highlights: > Chemical disorder affects martensitic transformation in Ni-Mn-Sn Heusler alloys. > Martensitic transition temperature depends on the L21-ferromagnetic fraction. > Grain boundaries induce drastic reduction of magnetization in milled Heusler alloys. > Magnetic properties of the milled Ni50Mn36Sn14 alloy get better after annealing. - Abstract: The effect of chemical disorder over the martensitic phase transformation of the Ni{sub 50}Mn{sub 36}Sn{sub 14} Heusler-type alloy was systematically investigated by performing X-ray diffractometry (DRX), DC magnetization and {sup 57}Fe-doping and {sup 119}Sn-Moessbauer spectroscopy measurements. DRX patterns are characteristics of a L2{sub 1}-type chemically disordered structure, where the presence of this disorder was first evaluated by analyzing the relative intensity of the (1 1 1) DRX reflection, which varies in the case of Fe-doped and practically disappears for the milled samples. In consequence, the magnetic properties of Fe-doped well-milled samples related to the martensitic phase transformation change substantially. 300 K {sup 57}Fe-Moessbauer spectroscopy data suggest that the changes in the magnetic properties related to the martensitic transformation are intrinsically correlated to the ferromagnetic and paramagnetic fractions, which are respectively associated with Fe atoms replacing Mn- and Sn-sites. In the case of milled samples, the drastic reduction of alloy magnetization was explained by the increase of the number of Mn atoms in the shell regions, which have a reduced magnetic moment comparatively to those in the grain cores. The magnetization change and the temperature transition in the martensitic transformation are governed by the grain core. The initial magnetic properties and martensitic transformation can be recovered by a subsequent annealing on the milled sample.

  4. Weak itinerant ferromagnetism in Heusler-type Fe2VAl0.95

    NARCIS (Netherlands)

    Sato, K.; Naka, T.; Taguchi, M.; Nakane, T.; Ishikawa, F.; Yamada, Y.; Takaesu, Y.; Nakama, T.; de Visser, A.; Matsushita, A.


    We report measurements of the magnetic, transport, and thermal properties of the Heusler-type compound Fe2VAl0.95. We show that while stoichiometric Fe2VAl is a nonmagnetic semimetal a 5% substitution on the Al site with the 3d elements Fe and V atoms leads to a ferromagnetic ground state with a

  5. Giant and reversible room-temperature elastocaloric effect in a single-crystalline Ni-Fe-Ga magnetic shape memory alloy

    National Research Council Canada - National Science Library

    Li, Yang; Zhao, Dewei; Liu, Jian


    Good mechanical properties and large adiabatic temperature change render Heusler-type Ni2FeGa-based magnetic shape memory alloys as a promising candidate material for solid-state mechanical cooling...

  6. Semimetallic behavior in Heusler-type Ru2TaAl and thermoelectric performance improved by off-stoichiometry (United States)

    Tseng, C. W.; Kuo, C. N.; Lee, H. W.; Chen, K. F.; Huang, R. C.; Wei, C.-M.; Kuo, Y. K.; Lue, C. S.


    We report a study of the temperature-dependent electrical resistivity, Seebeck coefficient, thermal conductivity, specific heat, and 27Al nuclear magnetic resonance (NMR) in Heusler-type Ru2TaAl , to shed light on its semimetallic behavior. While the temperature dependence of the electrical resistivity exhibits semiconductorlike behavior, the analysis of low-temperature specific heat reveals a residual Fermi-level density of states (DOS). Both observations can be realized by means of a semimetallic scenario with the Fermi energy located in the pseudogap of the electronic DOS. The NMR Knight shift and spin-lattice relaxation rate show activated behavior at higher temperatures, attributing to the thermally excited carriers across a pseudogap in Ru2TaAl . From the first-principles band structure calculations, we further provide a clear picture that an indirect overlap between electron and hole pockets is responsible for the formation of a pseudogap in the vicinity of the Fermi level of Ru2TaAl . In addition, an effort for improving the thermoelectric performance of Ru2TaAl has been made by investigating the thermoelectric properties of Ru1.95Ta1.05Al . We found significant enhancements in the electrical conductivity and Seebeck coefficient and marked reduction in the thermal conductivity via the off-stoichiometric approach. This leads to an increase in the figure-of-merit Z T value from 6.1 ×10-4 in Ru2TaAl to 3.4 ×10-3 in Ru1.95Ta1.05Al at room temperature. In this respect, a further improvement of thermoelectric performance based on Ru2TaAl through other off-stoichiometric attempts is highly probable.

  7. Crystallographic Characterization on Polycrystalline Ni-Mn-Ga Alloys with Strong Preferred Orientation

    Directory of Open Access Journals (Sweden)

    Zongbin Li


    Full Text Available Heusler type Ni-Mn-Ga ferromagnetic shape memory alloys can demonstrate excellent magnetic shape memory effect in single crystals. However, such effect in polycrystalline alloys is greatly weakened due to the random distribution of crystallographic orientation. Microstructure optimization and texture control are of great significance and challenge to improve the functional behaviors of polycrystalline alloys. In this paper, we summarize our recent progress on the microstructure control in polycrystalline Ni-Mn-Ga alloys in the form of bulk alloys, melt-spun ribbons and thin films, based on the detailed crystallographic characterizations through neutron diffraction, X-ray diffraction and electron backscatter diffraction. The presented results are expected to offer some guidelines for the microstructure modification and functional performance control of ferromagnetic shape memory alloys.

  8. Directional solidification and elastocaloric effect in a Ni45Mn44Sn11 magnetic shape memory alloy (United States)

    Sun, Wen; Liu, Jian; Zhao, Dewei; Zhang, Mingxiao


    In this work, the microstructural evolution, texture development and elastocaloric effect have been investigated in directionally solidified Heusler-type Ni45Mn44Sn11 alloys. A multi-phase structure is found in the as-grown sample, while only L21 phase exists after annealing. By employing the infrared thermography method, a significant average temperature change of  -7.5 K is observed in the annealed Ni45Mn44Sn11 alloy with a highly oriented [2 2 0] texture. Also, the formation of cracks and its influence on the mechanical stability and elastocaloric cooling behavior have been studied.

  9. Pressure effect of magnetic and electronic properties of Mn2PtGa Heusler alloy (United States)

    Xiao, Haibo; Wang, Ruilong; Xu, Linfang; Yang, Fujun; Yang, Changping


    First-principles calculations are performed to investigate pressure effects on structure, magnetism, martensitic phase transition and Curie temperatures of Mn2PtGa Heusler alloy in framework of the density functional theory. It is shown that Mn2PtGa prefer to crystallize in the inverse Heusler type structure. Besides, we predict an extraordinary occurrence of pressure induced metallic ferrimagnetism to half-metallic ferromagnetism transition in cubic phase of Mn2PtGa alloy under hydrostatic pressure up to 43 GPa and the half-metallic ferromagnetism is found to be robust even the lattice further compression to 90 GPa. However, with the pressure up to 100 GPa, the spin-down gap starts to close and the half metallicity begin to disappear, while with the pressure increasing from 100 GPa to 300 GPa, the alloy returns to metallic characteristic. In addition, the energy difference between the austenitic and martensitic phases is found to increase with increasing pressure followed by a decrease when pressure reaches to 43 GPa, which implies a variation trend of martensitic phase transition temperature. Furthermore, Curie temperatures in both austenitic and martensitic phases are estimated under pressure by using the standard mean-field approximation which agrees well with the theoretical results in literature. The robustness of the half metallicity, magnetic transition and the high Curie temperature under pressure make Mn2PtGa alloy a promising candidate for applications in spintronic devices.

  10. VANADIUM ALLOYS (United States)

    Smith, K.F.; Van Thyne, R.J.


    This patent deals with vanadium based ternary alloys useful as fuel element jackets. According to the invention the ternary vanadium alloys, prepared in an arc furnace, contain from 2.5 to 15% by weight titanium and from 0.5 to 10% by weight niobium. Characteristics of these alloys are good thermal conductivity, low neutron capture cross section, good corrosion resistance, good welding and fabricating properties, low expansion coefficient, and high strength.

  11. Giant magnetocaloric effect from reverse martensitic transformation in Ni–Mn–Ga–Cu ferromagnetic shape memory alloys

    Energy Technology Data Exchange (ETDEWEB)

    Sarkar, Sudip Kumar, E-mail: [Glass and Advanced Materials Division, Bhabha Atomic Research Centre, Mumbai, 400085 (India); Sarita [Glass and Advanced Materials Division, Bhabha Atomic Research Centre, Mumbai, 400085 (India); Babu, P.D. [UGC-DAE Consortium for Scientific Research, Mumbai Centre, BARC, Mumbai, 400085 (India); Biswas, Aniruddha [Glass and Advanced Materials Division, Bhabha Atomic Research Centre, Mumbai, 400085 (India); Siruguri, Vasudeva [UGC-DAE Consortium for Scientific Research, Mumbai Centre, BARC, Mumbai, 400085 (India); Krishnan, Madangopal [Glass and Advanced Materials Division, Bhabha Atomic Research Centre, Mumbai, 400085 (India)


    In an effort to produce Giant Magnetocaloric effect (GMCE) near room temperature, in a first ever such study, the austenite transformation temperature (A{sub s}) was fine tuned to ferromagnetic Curie temperature (T{sub C}) in Ferromagnetic Shape Memory Alloys (FSMA) and a large GMCE of ΔSM = −81.8 J/Kg-K was achieved in Ni{sub 50}Mn{sub 18.5}Cu{sub 6.5}Ga{sub 25} alloy during reverse martensitic transformation (heating cycle) for a magnetic field change of 9 T at 303 K. Fine tuning of A{sub s} with T{sub C} was achieved by Cu substitution in Ni{sub 50}Mn{sub 25−x}Cu{sub x}Ga{sub 25} (0 ≤ x ≤ 7.0)-based FSMAs. Characterizations of these alloys were carried out using Optical and Scanning Electron Microscopy, X-ray Diffraction (XRD), Differential Scanning Calorimetry (DSC) and DC magnetization measurements. Addition of Cu to stoichiometric Heusler type Ni{sub 2}MnGa increases the martensitic transformation temperatures and decreases T{sub C}. Concurrently, ΔSM increases with Cu addition and peaks at 6.5 at% Cu for which there is a virtual overlap between T{sub C} and A{sub s}. Maximum Refrigerant Capacity (RCP) of 327.0 J/Kg was also achieved in the heating cycle for 9 T field change at 303 K. Corresponding values for the cooling cycle measurements (measured during forward transformation) were 30.4 J/Kg-K and 123.5 J/Kg respectively for the same 6.5 at% Cu sample under the same thermo-magnetic conditions. - Highlights: • A{sub s} was fine tuned to T{sub C} in Cu substituted Ni{sub 50}Mn{sub 25−x}Cu{sub x}Ga{sub 25} (0 ≤ x ≤ 7.0) alloys. • MT temperature increases with Cu addition while T{sub C} decreases. • A virtual overlapping of A{sub s} with T{sub C} was found in Ni{sub 50}Mn{sub 18.5}Cu{sub 6.5}Ga{sub 25} alloys. • ΔSM = −81.8 J/Kg-K achieved from reverse MT for Δ(μ{sub 0}H) = 9 T at 303 K. • A highest RCP value of 94.6 J/Kg was observed for Δ(μ{sub 0}H) = 5 T in Cu:6.5 alloys.

  12. BRAZING ALLOYS (United States)

    Donnelly, R.G.; Gilliland, R.G.; Slaughter, G.M.


    A brazing alloy is described which, in the molten state, is characterized by excellent wettability and flowability and is capable of forming a corrosion-resistant brazed joint. At least one component of said joint is graphite and the other component is a corrosion-resistant refractory metal. The brazing alloy consists essentially of 40 to 90 wt % of gold, 5 to 35 wt% of nickel, and 1 to 45 wt% of tantalum. (AEC)

  13. Electrical Resistance Alloys and Low-Expansion Alloys

    DEFF Research Database (Denmark)

    Kjer, Torben


    The article gives an overview of electrical resistance alloys and alloys with low thermal expansion. The electrical resistance alloys comprise resistance alloys, heating alloys and thermostat alloys. The low expansion alloys comprise alloys with very low expansion coefficients, alloys with very low...

  14. Orthodontic silver brazing alloys. (United States)

    Brockhurst, P J; Pham, H L


    Orthodontic silver brazing alloys suffer from the presence of cadmium, excessive flow temperatures, and crevice corrosion on stainless steel. Seven alloys were examined. Two alloys contained cadmium. The lowest flow temperature observed was 629 degrees C for a cadmium alloy and 651 degrees C for two cadmium free alloys. Three alloys had corrosion resistance superior to the other solders. Addition of low melting temperature elements gallium and indium reduced flow temperature in some cases but produced brittleness in the brazing alloy.

  15. Rhenium alloying of tungsten heavy alloys

    Energy Technology Data Exchange (ETDEWEB)

    Bose, A.; Jerman, G.; German, R.M.


    Alloying experiments have been performed using rhenium additions to a classic 90 mass% tungsten heavy alloy. The mixed powder system was liquid phase sintered to full density at 1500/sup 0/C in 60 min. The rhenium modified alloys exhibited a smaller grain size, higher hardness, higher strength, and lower ductility than the unalloyed system. For an alloy with a composition of 84W-6Re-8Ni-2Fe, the sintered density was 17,4 Mg/m/sup 3/ with a yield strength of 815 MPa, tensile strength of 1180 MPa, and elongation to failure of 13%. This property combination results from the aggregate effects of grain size reduction and solid solution hardening due to rhenium. In the unalloyed system these properties require post-sintering swaging and aging; thus, alloying with rhenium is most attractive for applications where netshaping is desired, such as by powder injection molding. (orig.).

  16. Rhenium alloying of tungsten heavy alloys

    Energy Technology Data Exchange (ETDEWEB)

    German, R.M.; Bose, A.; Jerman, G.


    Alloying experiments were performed using rhenium additions to a classic 90 mass % tungsten heavy alloy. The mixed-powder system was liquid phase sintered to full density at 1500 C in 60 min The rhenium-modified alloys exhibited a smaller grain size, higher hardness, higher strength, and lower ductility than the unalloyed system. For an alloy with a composition of 84W-6Re-8Ni-2Fe, the sintered density was 17, 4 Mg/m{sup 3} with a yield strength of 815 MPa, tensile strength of 1180 MPa, and elongation to failure of 13%. This property combination results from the aggregate effects of grain size reduction and solid solution hardening due to rhenium. In the unalloyed system these properties require post-sintering swaging and aging; thus, alloying with rhenium is most attractive for applications where net shaping is desired, such as by powder injection molding.

  17. Nickel alloys development-Inconel alloys development

    Energy Technology Data Exchange (ETDEWEB)

    Park, Yong Soo; Uhm, Tae Sik; Kim, Taek Jun; Jeon, Yu Taek; Chang, Hyun Young [Yonsei University, Seoul (Korea, Republic of); Kim, Young Sik [Andong National University, Andon (Korea, Republic of)


    This report dealt with the evaluation of Alloy 600 and alloy 690 of steam= generator materials. The experimental alloys were divided into two groups. ; Seamless tubings made by different ingot, and Mo-modified alloys. Thermal treatment had no influenced on the anodic polarization resistance in some caustic solution, but improved stress corrosion resistance by CERT. The effect of SO{sub 4}{sup =} ions reduced markedly caustic SCC resistance. The corrosion mode by 70 days and 120 days C-ring tests revealed the intergranular corrosion instead of stress corrosion cracking. Mo addition on the corrosion resistance of Alloy 690M showed beneficial effect in neutral and acidic solutions, but a little effect in caustic solutions. However, the caustic stress corrosion resistance was improved by the addition of molybdenum. 27 refs., 84 figs., 5 tabs. (author)

  18. High strength alloys

    Energy Technology Data Exchange (ETDEWEB)

    Maziasz, Phillip James; Shingledecker, John Paul; Santella, Michael Leonard; Schneibel, Joachim Hugo; Sikka, Vinod Kumar; Vinegar, Harold J.; John, Randy Carl; Kim, Dong Sub


    High strength metal alloys are described herein. At least one composition of a metal alloy includes chromium, nickel, copper, manganese, silicon, niobium, tungsten and iron. System, methods, and heaters that include the high strength metal alloys are described herein. At least one heater system may include a canister at least partially made from material containing at least one of the metal alloys. At least one system for heating a subterranean formation may include a tublar that is at least partially made from a material containing at least one of the metal alloys.

  19. High strength alloys

    Energy Technology Data Exchange (ETDEWEB)

    Maziasz, Phillip James [Oak Ridge, TN; Shingledecker, John Paul [Knoxville, TN; Santella, Michael Leonard [Knoxville, TN; Schneibel, Joachim Hugo [Knoxville, TN; Sikka, Vinod Kumar [Oak Ridge, TN; Vinegar, Harold J [Bellaire, TX; John, Randy Carl [Houston, TX; Kim, Dong Sub [Sugar Land, TX


    High strength metal alloys are described herein. At least one composition of a metal alloy includes chromium, nickel, copper, manganese, silicon, niobium, tungsten and iron. System, methods, and heaters that include the high strength metal alloys are described herein. At least one heater system may include a canister at least partially made from material containing at least one of the metal alloys. At least one system for heating a subterranean formation may include a tubular that is at least partially made from a material containing at least one of the metal alloys.

  20. Creep Resistant Zinc Alloy

    Energy Technology Data Exchange (ETDEWEB)

    Frank E. Goodwin


    This report covers the development of Hot Chamber Die Castable Zinc Alloys with High Creep Strengths. This project commenced in 2000, with the primary objective of developing a hot chamber zinc die-casting alloy, capable of satisfactory service at 140 C. The core objectives of the development program were to: (1) fill in missing alloy data areas and develop a more complete empirical model of the influence of alloy composition on creep strength and other selected properties, and (2) based on the results from this model, examine promising alloy composition areas, for further development and for meeting the property combination targets, with the view to designing an optimized alloy composition. The target properties identified by ILZRO for an improved creep resistant zinc die-casting alloy were identified as follows: (1) temperature capability of 1470 C; (2) creep stress of 31 MPa (4500 psi); (3) exposure time of 1000 hours; and (4) maximum creep elongation under these conditions of 1%. The project was broadly divided into three tasks: (1) Task 1--General and Modeling, covering Experimental design of a first batch of alloys, alloy preparation and characterization. (2) Task 2--Refinement and Optimization, covering Experimental design of a second batch of alloys. (3) Task 3--Creep Testing and Technology transfer, covering the finalization of testing and the transfer of technology to the Zinc industry should have at least one improved alloy result from this work.

  1. Biocompatibility of dental alloys

    Energy Technology Data Exchange (ETDEWEB)

    Braemer, W. [Heraeus Kulzer GmbH and Co. KG, Hanau (Germany)


    Modern dental alloys have been used for 50 years to produce prosthetic dental restorations. Generally, the crowns and frames of a prosthesis are prepared in dental alloys, and then veneered by feldspar ceramics or composites. In use, the alloys are exposed to the corrosive influence of saliva and bacteria. Metallic dental materials can be classified as precious and non-precious alloys. Precious alloys consist of gold, platinum, and small amounts of non-precious components such as copper, tin, or zinc. The non-precious alloys are based on either nickel or cobalt, alloyed with chrome, molybdenum, manganese, etc. Titanium is used as Grade 2 quality for dental purposes. As well as the dental casting alloys, high purity electroplated gold (99.8 wt.-%) is used in dental technology. This review discusses the corrosion behavior of metallic dental materials with saliva in ''in vitro'' tests and the influence of alloy components on bacteria (Lactobacillus casei and Streptococcus mutans). The test results show that alloys with high gold content, cobalt-based alloys, titanium, and electroplated gold are suitable for use as dental materials. (orig.)

  2. Impact of anisotropy on antiferromagnet rotation in Heusler-type ferromagnet/antiferromagnet epitaxial bilayers (United States)

    Hajiri, T.; Matsushita, M.; Ni, Y. Z.; Asano, H.


    We report the magnetotransport properties of ferromagnet (FM)/antiferromagnet (AFM) Fe2CrSi /Ru2MnGe epitaxial bilayers using current-in-plane configurations. Above the critical thickness of the Ru2MnGe layer to induce exchange bias, symmetric and asymmetric curves were observed in response to the direction of FM magnetocrystalline anisotropy. Because each magnetoresistance curve showed full and partial AFM rotation, the magnetoresistance curves imply the impact of the Fe2CrSi magnetocrystalline anisotropy to govern the AFM rotation. The maximum magnitude of the angular-dependent resistance-change ratio of the bilayers is more than an order of magnitude larger than that of single-layer Fe2CrSi films, resulting from the reorientation of AFM spins via the FM rotation. These results highlight the essential role of controlling the AFM rotation and reveal a facile approach to detect the AFM moment even in current-in-plane configurations in FM/AFM bilayers.

  3. Structural and magnetic properties in Heusler-type ferromagnet/antiferromagnet bilayers (United States)

    Fukatani, N.; Inagaki, K.; Miyawaki, T.; Ueda, K.; Asano, H.


    The structure and magnetic properties of Heusler ferromagnet/antiferromagnet (FM/AFM) bilayers were investigated. Structural characterization revealed that Fe2CrSi/Ru2MnGe bilayers were epitaxially grown with an L21 ordered structure when the Ru2MnGe growth temperature was 573 K. The magnetization curve indicates that exchange bias occurs in the Fe2CrSi/Ru2MnGe bilayers at 77 K. The appearance of an exchange-anisotropy field Hex depends on the growth of Ru2MnGe layer, indicating that the exchange bias originates from the epitaxial Fe2CrSi/Ru2MnGe interface. The exchange anisotropy energy Jk of the Fe2CrSi/Ru2MnGe and Co2MnGe/Ru2MnGe bilayer systems appears to follow a Heisenberg-like exchange coupling model. This suggests that the Cr and Mn interface atoms in the FM layers play significant roles in exchange coupling in the Fe2CrSi/Ru2MnGe and Co2MnGe/Ru2MnGe bilayer systems, respectively.

  4. Catalyst Alloys Processing (United States)

    Tan, Xincai


    Catalysts are one of the key materials used for diamond formation at high pressures. Several such catalyst products have been developed and applied in China and around the world. The catalyst alloy most widely used in China is Ni70Mn25Co5 developed at Changsha Research Institute of Mining and Metallurgy. In this article, detailed techniques for manufacturing such a typical catalyst alloy will be reviewed. The characteristics of the alloy will be described. Detailed processing of the alloy will be presented, including remelting and casting, hot rolling, annealing, surface treatment, cold rolling, blanking, finishing, packaging, and waste treatment. An example use of the catalyst alloy will also be given. Industrial experience shows that for the catalyst alloy products, a vacuum induction remelt furnace can be used for remelting, a metal mold can be used for casting, hot and cold rolling can be used for forming, and acid pickling can be used for metal surface cleaning.

  5. Low activation ferritic alloys (United States)

    Gelles, D.S.; Ghoniem, N.M.; Powell, R.W.


    Low activation ferritic alloys, specifically bainitic and martensitic stainless steels, are described for use in the production of structural components for nuclear fusion reactors. They are designed specifically to achieve low activation characteristics suitable for efficient waste disposal. The alloys essentially exclude molybdenum, nickel, nitrogen and niobium. Strength is achieved by substituting vanadium, tungsten, and/or tantalum in place of the usual molybdenum content in such alloys.

  6. Copper-tantalum alloy (United States)

    Schmidt, Frederick A.; Verhoeven, John D.; Gibson, Edwin D.


    A tantalum-copper alloy can be made by preparing a consumable electrode consisting of an elongated copper billet containing at least two spaced apart tantalum rods extending longitudinally the length of the billet. The electrode is placed in a dc arc furnace and melted under conditions which co-melt the copper and tantalum to form the alloy.

  7. Ultrahigh temperature intermetallic alloys

    Energy Technology Data Exchange (ETDEWEB)

    Brady, M.P.; Zhu, J.H.; Liu, C.T.; Tortorelli, P.F.; Wright, J.L.; Carmichael, C.A.; Walker, L.R. [Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.


    A new family of Cr-Cr{sub 2}X based alloys with fabricability, mechanical properties, and oxidation resistance superior to previously developed Cr-Cr{sub 2}Nb and Cr-Cr{sub 2}Zr based alloys has been identified. The new alloys can be arc-melted/cast without cracking, and exhibit excellent room temperature and high-temperature tensile strengths. Preliminary evaluation of oxidation behavior at 1100 C in air indicates that the new Cr-Cr{sub 2}X based alloys form an adherent chromia-based scale. Under similar conditions, Cr-Cr{sub 2}Nb and Cr-Cr{sub 2}Zr based alloys suffer from extensive scale spallation.

  8. Brazing dissimilar aluminum alloys (United States)

    Dalalian, H.


    Dip-brazing process joins aluminum castings to aluminum sheet made from different aluminum alloy. Process includes careful cleaning, surface preparation, and temperature control. It causes minimum distortion of parts.

  9. Machining of titanium alloys

    CERN Document Server


    This book presents a collection of examples illustrating the resent research advances in the machining of titanium alloys. These materials have excellent strength and fracture toughness as well as low density and good corrosion resistance; however, machinability is still poor due to their low thermal conductivity and high chemical reactivity with cutting tool materials. This book presents solutions to enhance machinability in titanium-based alloys and serves as a useful reference to professionals and researchers in aerospace, automotive and biomedical fields.

  10. Pareto-optimal alloys

    DEFF Research Database (Denmark)

    Bligaard, Thomas; Johannesson, Gisli Holmar; Ruban, Andrei


    and the cost. In this letter we present a database consisting of the lattice parameters, bulk moduli, and heats of formation for over 64 000 ordered metallic alloys, which has been established by direct first-principles density-functional-theory calculations. Furthermore, we use a concept from economic theory......, the Pareto-optimal set, to determine optimal alloy solutions for the compromise between low compressibility, high stability, and cost....

  11. Martensitic transformation and magnetic properties of manganese-rich Ni-Mn-In and Ni-Mn-Sn Heusler alloys; Untersuchung der martensitischen Umwandlung und der magnetischen Eigenschaften Mangan-reicher Ni-Mn-In- und Ni-Mn-Sn-Heusler-Legierungen

    Energy Technology Data Exchange (ETDEWEB)

    Krenke, T.


    0.12 % appear. Additionally, the alloys Ni{sub 50}Mn{sub 35}Sn{sub 15}, Ni{sub 50}Mn{sub 37}Sn{sub 13}, Ni{sub 50}Mn{sub 34}In{sub 16}, Ni{sub 51.5}Mn{sub 33}In{sub 15.5}, and Ni{sub 50}Mn{sub 35}In{sub 15} show remarkable magnetocaloric properties. The entropy change {delta}S, which is determined by the sign of {theta}M(T)/{theta}T, is positive in all cases. The absolute values of {delta}S reach up to +23 JK{sup -1}kg{sup -1} (Ni{sub 50}Mn{sub 35}In{sub 15}) at room temperature, which are, up to now, the largest values ever obtained in Heusler type alloys. This means that these alloys exhibit an inverse magnetocaloric effect, whereby the samples cool by adiabatic application of an external magnetic field. (orig.)

  12. Impact toughness of laser alloyed aluminium AA1200 alloys

    CSIR Research Space (South Africa)

    Mabhali, Luyolo AB


    Full Text Available Laser surface alloying of aluminium AA1200 was performed with a 4kW Nd:YAG laser and impact resistance of the alloys was investigated. The alloying powders were a mixture of Ni, Ti and SiC in different proportions. Surfaces reinforced...


    Directory of Open Access Journals (Sweden)

    Berat Barıs BULDUM


    Full Text Available Magnesium is the lightest structural metal. Magnesium alloys have a hexagonal lattice structure, which affects the fundamental properties of these alloys. Plastic deformation of the hexagonal lattice is more complicated than in cubic latticed metals like aluminum, copper and steel. Magnesium alloy developments have traditionally been driven by industry requirements for lightweight materials to operate under increasingly demanding conditions. Magnesium alloys have always been attractive to designers due to their low density, only two thirds that of aluminium and its alloys [1]. The element and its alloys take a big part of modern industry needs. Especially nowadays magnesium alloys are used in automotive and mechanical (trains and wagons manufacture, because of its lightness and other features. Magnesium and magnesium alloys are the easiest of all metals to machine, allowing machining operations at extremely high speed. All standard machining operations such as turning, drilling, milling, are commonly performed on magnesium parts.

  14. Structural thermodynamics of alloys

    CERN Document Server

    Manenc, Jack


    Technical progress has for a very long time been directly dependent on progress in metallurgy, which is itself connected with improvements in the technology of alloys. Metals are most frequently used in the form of alloys for several reasons: the quantity of pure metal in its native state in the earth's crust is very limited; pure metals must be extracted from ores which are themselves impure. Finally, the methods of treatment used lead more easily to alloys than to pure metals. The most typical case is that of iron, where a pure ore may be found, but which is the starting point for cast iron or steel, alloys of iron and carbon. In addition, the properties of alloys are in general superior to those of pure metals and modem metallurgy consists of controlling these properties so as to make them conform to the requirements of the design office. Whilst the engineer was formerly compelled to adapt his designs and constructions to the materials available, such as wood, stone, bronze, iron, cast iron and ordinary st...



    Berat Barıs BULDUM; Aydın SIK; Iskender OZKUL


    Magnesium is the lightest structural metal. Magnesium alloys have a hexagonal lattice structure, which affects the fundamental properties of these alloys. Plastic deformation of the hexagonal lattice is more complicated than in cubic latticed metals like aluminum, copper and steel. Magnesium alloy developments have traditionally been driven by industry requirements for lightweight materials to operate under increasingly demanding conditions. Magnesium alloys have always been attra...

  16. De-alloyed platinum nanoparticles (United States)

    Strasser, Peter [Houston, TX; Koh, Shirlaine [Houston, TX; Mani, Prasanna [Houston, TX; Ratndeep, Srivastava [Houston, TX


    A method of producing de-alloyed nanoparticles. In an embodiment, the method comprises admixing metal precursors, freeze-drying, annealing, and de-alloying the nanoparticles in situ. Further, in an embodiment de-alloyed nanoparticle formed by the method, wherein the nanoparticle further comprises a core-shell arrangement. The nanoparticle is suitable for electrocatalytic processes and devices.

  17. Silumins alloy crystallization

    Directory of Open Access Journals (Sweden)

    S. Pietrowski


    Full Text Available This paper presents the results of research, by ATD method, of hypo-, near- and hyperutectic silumins crystallization containing the following alloying additives: Mg, Ni, Cu, Cr, Mo, W, V. It has been shown that, depending on their concentration may crystallize pre-eutectic or eutectic multicomponent phases containing these alloy additives. It has been revealed that any subsequent crystallizable phase nucleate and grows near the liquid/former crystallized phase interface. In multiphases compound also falls the silicon, resulting in a reduction in its quantity and the fragmentation in the eutectic mixture. As a result, it gets a high hardness of silumins in terms of 110-220HB.

  18. Structural and magnetic properties of antiferromagnetic Heusler Ru2MnGe Epitaxial thin films (United States)

    Fukatani, Naoto; Fujita, Hirohito; Miyawaki, Tetsuya; Ueda, Kenji; Asano, Hidefumi


    Structural and magnetic properties were investigated for Heusler-type alloy Ru2MnGe thin films. Ru2MnGe films on MgO substrate were subjected to an in-plane compressive strain, and exhibited enhanced antiferromagnetic (AFM) transition temperature ( T N ) up to 353 K, which exceeds by 37 K from the cubic bulk material ( T N = 316 K). We also observed the exchange coupling between Ru2MnGe and Heusler-type ferromagnetic (FM) half-metal Fe2CrSi thin films. The present AFM Heusler alloy with relatively high T N is useful to fabricate high-quality all Heusler-type half-metal AFM/FM junctions and is a promising material for the emerging field of AFM spintronics.

  19. Advanced ordered intermetallic alloy deployment

    Energy Technology Data Exchange (ETDEWEB)

    Liu, C.T.; Maziasz, P.J.; Easton, D.S. [Oak Ridge National Lab., TN (United States)


    The need for high-strength, high-temperature, and light-weight materials for structural applications has generated a great deal of interest in ordered intermetallic alloys, particularly in {gamma}-based titanium aluminides {gamma}-based TiAl alloys offer an attractive mix of low density ({approximately}4g/cm{sup 3}), good creep resistance, and high-temperature strength and oxidation resistance. For rotating or high-speed components. TiAl also has a high damping coefficient which minimizes vibrations and noise. These alloys generally contain two phases. {alpha}{sub 2} (DO{sub 19} structure) and {gamma} (L 1{sub 0}), at temperatures below 1120{degrees}C, the euticoid temperature. The mechanical properties of TiAl-based alloys are sensitive to both alloy compositions and microstructure. Depending on heat-treatment and thermomechanical processing, microstructures with near equiaxed {gamma}, a duplex structure (a mix of the {gamma} and {alpha}{sub 2} phases) can be developed in TiAl alloys containing 45 to 50 at. % Al. The major concern for structural use of TiAl alloys is their low ductility and poor fracture resistance at ambient temperatures. The purpose of this project is to improve the fracture toughness of TiAl-based alloys by controlling alloy composition, microstructure and thermomechanical treatment. This work is expected to lead to the development of TiAl alloys with significantly improved fracture toughness and tensile ductility for structural use.

  20. Magnesium-lithium casting alloys (United States)

    Latenko, V. P.; Silchenko, T. V.; Tikhonov, V. A.; Maltsev, V. P.; Korablin, V. P.


    The strength properties of magnesium-lithium alloys at room, low, and high temperatures are investigated. It is found that the alloys may have practical application at ambient temperatures up to 100 C, that negative temperatures have a favorable influence on the alloy strength, and that cyclic temperature variations have practically no effect on the strength characteristics. The influence of chemical coatings on corrosion resistance of the MgLi alloys is examined. Several facilities based on pressure casting machines, low-pressure casting machines, and magnetodynamic pumps were designed for producing MgLi alloy castings. Results were obtained for MgLi alloys reinforced with fibers having a volumetric content of 15%.

  1. Two phase titanium aluminide alloy

    Energy Technology Data Exchange (ETDEWEB)

    Deevi, Seetharama C. (Midlothian, VA); Liu, C. T. (Oak Ridge, TN)


    A two-phase titanic aluminide alloy having a lamellar microstructure with little intercolony structures. The alloy can include fine particles such as boride particles at colony boundaries and/or grain boundary equiaxed structures. The alloy can include alloying additions such as .ltoreq.10 at % W, Nb and/or Mo. The alloy can be free of Cr, V, Mn, Cu and/or Ni and can include, in atomic %, 45 to 55% Ti, 40 to 50% Al, 1 to 5% Nb, 0.3 to 2% W, up to 1% Mo and 0.1 to 0.3% B. In weight %, the alloy can include 57 to 60% Ti, 30 to 32% Al, 4 to 9% Nb, up to 2% Mo, 2 to 8% W and 0.02 to 0.08% B.

  2. Materials data handbook, Inconel alloy 718 (United States)

    Sessler, J.; Weiss, V.


    Materials data handbook on Inconel alloy 718 includes data on the properties of the alloy at cryogenic, ambient, and elevated temperatures and other pertinent engineering information required for the design and fabrication of components and equipment utilizing this alloy.

  3. Nanoscale Alloying in Electrocatalysts

    Directory of Open Access Journals (Sweden)

    Shiyao Shan


    Full Text Available In electrochemical energy conversion and storage, existing catalysts often contain a high percentage of noble metals such as Pt and Pd. In order to develop low-cost electrocatalysts, one of the effective strategies involves alloying noble metals with other transition metals. This strategy promises not only significant reduction of noble metals but also the tunability for enhanced catalytic activity and stability in comparison with conventional catalysts. In this report, some of the recent approaches to developing alloy catalysts for electrocatalytic oxygen reduction reaction in fuel cells will be highlighted. Selected examples will be also discussed to highlight insights into the structural and electrocatalytic properties of nanoalloy catalysts, which have implications for the design of low-cost, active, and durable catalysts for electrochemical energy production and conversion reactions.

  4. Ultralight Magnesium-Lithium Alloys


    A. Białobrzeski; K. Saja; Hubner, K.


    The article gives basic information on the chief constituents of Mg-Li alloys and on their expected properties. A schematic representation and technical performance of a pilot stand for melting and pouring of reactive ultralight magnesium-based alloys have been presented. The preliminary data regarding the manufactured magnesium alloys with about 2-3 % Li and about 10 % Li have been given in the form of microstructures and chemical compositions.

  5. Titanium alloys for aerospace applications

    Energy Technology Data Exchange (ETDEWEB)

    Peters, M.; Leyens, C. [DLR-German Aerospace Center, D-51170 Koeln (Germany); Kumpfert, J. [Airbus Industrie, F-31707 Blagnac (France); Ward, C.H. [US Air Force Research Laboratory, London NW1 5TH (United Kingdom)


    There is probably no other material more closely related to aerospace than titanium and its alloys. With a density of 4.5 g/cm{sup 3}, titanium alloys are only about half as heavy as steel or Ni-based superalloys, yielding an excellent strength-to-weight ratio. Furthermore, they have exceptional corrosion resistance. The use of titanium alloys in the aerospace sector will be highlighted including airframe, engine, helicopter, and space applications. (Abstract Copyright [2003], Wiley Periodicals, Inc.)

  6. Alloy catalyst material

    DEFF Research Database (Denmark)


    The present invention relates to a novel alloy catalyst material for use in the synthesis of hydrogen peroxide from oxygen and hydrogen, or from oxygen and water. The present invention also relates to a cathode and an electrochemical cell comprising the novel catalyst material, and the process use...... of the novel catalyst material for synthesising hydrogen peroxide from oxygen and hydrogen, or from oxygen and water....

  7. Aluminum alloy impact sparkling

    Directory of Open Access Journals (Sweden)

    M. Dudyk


    Full Text Available The cast machine parts are widely used in many branches of industry. A very important issue is gaining the appropriate knowledge relating to the application of castings in places of explosion risks including but not limited to mining, chemical industry and rescue works. A possibility of explosion risks occurrence following the impact sparkling of the cast metal parts is still not solved problem in scientific research. In relation to this issue, in this article, the results of the study are presented, and relating to the tendency to impact sparkling of the aluminium alloys used in machine building. On the grounds of the results obtained, it was demonstrated that the registered impact sparkles bunches of feathers from the analyzed alloys: AlSi7Mg, (AK7; AlSi9Mg, (AK9; AlSi6Cu4, (AK64 and AlSi11, (AK11 show significant differences between each other. The quantitative analysis of the temperature distribution and nuclei surface area performed on the example of the alloy AK9 (subjected to defined period of corrosion allows for the statement that they are dangerous in conditions of explosion risk. Following this fact, designers and users of machine parts made from these materials should not use them in conditions where the explosive mixtures occur.


    Coffinberry, A.S.


    A low melting point plutonium alloy useful as fuel is a homogeneous liquid metal fueled nuclear reactor is described. Vessels of tungsten or tantalum are useful to contain the alloy which consists essentially of from 10 to 30 atomic per cent copper and the balance plutonium and cerium. with the plutontum not in excess of 50 atomic per cent.

  9. Shape memory alloy based motor

    Indian Academy of Sciences (India) Keywords. Shape Memory Alloy (SMA); poly phase; rotary actuator; torque; ripple. Abstract. Design and characterization of a new shape memory alloy wire based Poly Phase Motor has been reported in this paper. The motor can be used either in stepping mode or ...

  10. Mo-Si alloy development

    Energy Technology Data Exchange (ETDEWEB)

    Liu, C.T.; Heatherly, L.; Wright, J.L. [Oak Ridge National Lab., TN (United States)


    The objective of this task is to develop new-generation corrosion-resistant Mo-Si intermetallic alloys as hot components in advanced fossil energy conversion and combustion systems. The initial effort is devoted to Mo{sub 5}-Si{sub 3}-base (MSB) alloys containing boron additions. Three MSB alloys based on Mo-10.5Si-1.1B (wt %), weighing 1500 g were prepared by hot pressing of elemental and alloy powders at temperatures to 1600{degrees}C in vacuum. Microporosities and glassy-phase (probably silicate phases) formations are identified as the major concerns for preparation of MSB alloys by powder metallurgy. Suggestions are made to alleviate the problems of material processing.

  11. Nickel alloys and high-alloyed special stainless steels. Properties, manufacturing, applications. 4. compl. rev. ed.

    Energy Technology Data Exchange (ETDEWEB)

    Heubner, Ulrich; Kloewer, Jutta; Alves, Helena; Behrens, Rainer; Schindler, Claudius; Wahl, Volker; Wolf, Martin


    This book contains the following eight topics: 1. Nickel alloys and high-alloy special stainless steels - Material overview and metallurgical principles (U. Heubner); 2. Corrosion resistance of nickel alloys and high-alloy special stainless steels (U. Heubner); 3. Welding of nickel alloys and high-alloy special stainless steels (T. Hoffmann, M. Wolf); 4. High-temperature materials for industrial plant construction (J. Kloewer); 5. Nickel alloys and high-alloy special stainless steels as hot roll clad composites-a cost-effective alternative (C. Schindler); 6. Selected examples of the use of nickel alloys and high-alloy special stainless steels in chemical plants (H. Alves); 7. The use of nickel alloys and stainless steels in environmental engineering (V. Wahl); 8: Nickel alloys and high-alloy special stainless steels for the oil and gas industry (R. Behrens).

  12. Stress Corrosion Cracking of Certain Aluminum Alloys (United States)

    Hasse, K. R.; Dorward, R. C.


    SC resistance of new high-strength alloys tested. Research report describes progress in continuing investigation of stress corrosion (SC) cracking of some aluminum alloys. Objective of program is comparing SC behavior of newer high-strength alloys with established SC-resistant alloy.

  13. Heat storage in alloy transformations (United States)

    Birchenall, C. E.


    The feasibility of using metal alloys as thermal energy storage media was investigated. The elements selected as candidate media were limited to aluminum, copper, magnesium, silicon, zinc, calcium, and phosphorus on the basis of low cost and latent heat of transformation. Several new eutectic alloys and ternary intermetallic phases were determined. A new method employing X-ray absorption techniques was developed to determine the coefficients of thermal expansion of both the solid and liquid phases and the volume change during phase transformation. The method and apparatus are discussed and the experimental results are presented for aluminum and two aluminum-eutectic alloys. Candidate materials were evaluated to determine suitable materials for containment of the metal alloys. Graphite was used to contain the alloys during the volume change measurements. Silicon carbide was identified as a promising containment material and surface-coated iron alloys were also evaluated. System considerations that are pertinent if alloy eutectics are used as thermal energy storage media are discussed. Potential applications to solar receivers and industrial furnaces are illustrated schematically.

  14. Magnesium alloying - some metallurgical aspects

    Energy Technology Data Exchange (ETDEWEB)

    Pekgueleryuez, M.Oe. [Inst. of Magnesium Technology (ITM), Quebec, PQ (Canada); Avedesian, M.M. [Inst. of Magnesium Technology (ITM), Quebec, PQ (Canada)


    The incentive for alloy development is the need for new materials with a combination of better performance properties at lower cost. Over the past 45 years the development of new Mg alloys has lagged steel, aluminum, copper, zinc and other metals. The reasons for the slow development of Mg alloys since the 1920`s may have been the real and perceived short comings of Mg which has limited the wide acceptance of the metal by the various industries. In addition the advent of high performance plastics has put new competitive pressure on magnesium. Upon a close look, it can be seen that Mg does not possess a full alloy spectrum; there are really three to four major commercial alloy systems such as Mg-Al-Zn, Mg-Al, Mg-Zn and Mg-Rare Earths. In 1990 most magnesium usage for structural applications was in diecasting (36 kt) and 90% of this was in one alloy, AZ91D. This shows that Mg has not yet fully realized its potential as a structural metal. The 1990`s may, however, generate a long term driving force for magnesium alloy development due to the fact that industries such as the transport industry are faced more than ever with weight reduction objectives. They are driven to use light weight metals and will continue to do so in the future. Magnesium which is the lightest structural metal offers an attractive solution and the interest in the metal is increasing rapidly. This paper attempts to address the major problems of magnesium alloys with the view of identifying opportunities for cost-competitive ways of eliminating the problems of magnesium via alloy and microstructural design. A basic understanding of the fundamental mechanisms affecting strength and creep of Mg is also presented. (orig.)

  15. Dendritic Alloy Solidification Experiment (DASE) (United States)

    Beckermann, C.; Karma, A.; Steinbach, I.; deGroh, H. C., III


    A space experiment, and supporting ground-based research, is proposed to study the microstructural evolution in free dendritic growth from a supercooled melt of the transparent model alloy succinonitrile-acetone (SCN-ACE). The research is relevant to equiaxed solidification of metal alloy castings. The microgravity experiment will establish a benchmark for testing of equiaxed dendritic growth theories, scaling laws, and models in the presence of purely diffusive, coupled heat and solute transport, without the complicating influences of melt convection. The specific objectives are to: determine the selection of the dendrite tip operating state, i.e. the growth velocity and tip radius, for free dendritic growth of succinonitrile-acetone alloys; determine the growth morphology and sidebranching behavior for freely grown alloy dendrites; determine the effects of the thermal/solutal interactions in the growth of an assemblage of equiaxed alloy crystals; determine the effects of melt convection on the free growth of alloy dendrites; measure the surface tension anisotropy strength of succinon itrile -acetone alloys establish a theoretical and modeling framework for the experiments. Microgravity experiments on equiaxed dendritic growth of alloy dendrites have not been performed in the past. The proposed experiment builds on the Isothermal Dendritic Growth Experiment (IDGE) of Glicksman and coworkers, which focused on the steady growth of a single crystal from pure supercooled melts (succinonitrile and pivalic acid). It also extends the Equiaxed Dendritic Solidification Experiment (EDSE) of the present investigators, which is concerned with the interactions and transients arising in the growth of an assemblage of equiaxed crystals (succinonitrile). However, these experiments with pure substances are not able to address the issues related to coupled heat and solute transport in growth of alloy dendrites.

  16. Laser surface alloying on aluminum and its alloys: A review (United States)

    Chi, Yiming; Gu, Guochao; Yu, Huijun; Chen, Chuanzhong


    Aluminum and its alloys have been widely used in aerospace, automotive and transportation industries owing to their excellent properties such as high specific strength, good ductility and light weight. Surface modification is of crucial importance to the surface properties of aluminum and its alloys since high coefficient of friction, wear characteristics and low hardness have limited their long term performance. Laser surface alloying is one of the most effective methods of producing proper microstructure by means of non-equilibrium solidification which results from rapid heating and cooling. In this paper, the influence of different processing parameters, such as laser power and scanning velocity is discussed. The developments of various material systems including ceramics, metals or alloys, and metal matrix composites (MMCs) are reviewed. The microstructure, hardness, wear properties and other behaviors of laser treated layer are analyzed. Besides, the existing problems during laser surface treatment and the corresponding solutions are elucidated and the future developments are predicted.

  17. Alloying and Casting Furnace for Shape Memory Alloys Project (United States)

    National Aeronautics and Space Administration — The concept in the proposed project is to create a melting, alloying and casting furnace for the processing titanium based SMA using cold crucible techniques. The...

  18. Laser surface alloying of aluminium-transition metal alloys

    Directory of Open Access Journals (Sweden)

    Almeida, A.


    Full Text Available Laser surface alloying has been used as a tool to produce hard and corrosion resistant Al-transition metal (TM alloys. Cr and Mo are particularly interesting alloying elements to produce stable highstrength alloys because they present low diffusion coefficients and solid solubility in Al. To produce Al-TM surface alloys a two-step laser process was developed: firstly, the material is alloyed using low scanning speed and secondly, the microstructure is modified by a refinement step. This process was used in the production of Al-Cr, Al-Mo and Al-Nb surface alloys by alloying Cr, Mo or Nb powder into an Al and 7175 Al alloy substrate using a CO2 laser. This paper presents a review of the work that has been developed at Instituto Superior Tecnico on laser alloying of Al-TM alloys, over the last years.

    En el presente trabajo se estudia la aleación superficial mediante láser de aluminio con metales de transición. El cromo y el molibdeno son particularmente interesantes porque producen aleaciones de alta resistencia y por el bajo coeficiente de difusión y solución sólida en aluminio. Para producir estas aleaciones se ha seguido un procedimiento desarrollado en dos partes. En primer lugar, el material se alea usando una baja velocidad de procesado y en segundo lugar la estructura se modifica mediante un refinamiento posterior. Este procedimiento se ha empleado en la producción de aleaciones Al-Cr, Al-Mo y Al-Nb mediante aleación con láser de CO2 de polvos de Cr, Mo o Nb en aluminio y la aleación 7175. Este trabajo es una revisión del desarrollado en el Instituto Superior Técnico de Lisboa en los últimos años.

  19. Development of magnesium diecasting alloys

    Energy Technology Data Exchange (ETDEWEB)

    King, J.F. (Magnesium Elektron, Manchester (United Kingdom))


    Although there are many fascinating aspects of the development of magnesium diecasting alloys, the volume potential of the automotive industry has always had a major influence on justifying the significant R and D expenditure necessary for this task. Apart from a review of the history of magnesium diecasting alloy development, I would therefore like to focus this presentation on aspects of development specifically relevant to current automotive requirements. (orig.)

  20. Wettability of magnesium based alloys (United States)

    Ornelas, Victor Manuel

    The premise of this project was to determine the wettability behavior of Mg-based alloys using three different liquids. Contact angle measurements were carried out along with utilizing the Zisman method for obtaining values for the critical surface tension. Adhesion energy values were also found through the use of the Young-Dupre equation. This project utilized the Mg-based alloy Mg-2Zn-2Gd with supplemented alpha-Minimum Essential Medium (MEM), Phosphate Buffer Saline solution (PBS), and distilled water. These three liquids are commonly used in cell cultivation and protein adsorption studies. Supplemented alpha-MEM consisted of alpha-MEM, fetal bovine serum, and penicillin-streptomycin. Mg-2Zn-2Gd was used because of observed superior mechanical properties and better corrosion resistance as compared to conventional Mg-alloys. These attractive properties have made it possible for this alloy to be used in biomedical devices within the human body. However, the successful use of this alloy system in the human body requires knowledge in the response of protein adsorption on the alloy surface. Protein adsorption depends on many parameters, but one of the most important factors is the wettability behavior at the surface.

  1. Microstructural studies on Alloy 693

    Energy Technology Data Exchange (ETDEWEB)

    Halder, R.; Dutta, R.S. [Materials Science Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Sengupta, P., E-mail: [Materials Science Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Samajdar, I. [Dept. of Metall. Engg. and Mater. Sci., Indian Institute of Technology Bombay, Mumbai 400 072 (India); Dey, G.K. [Materials Science Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India)


    Superalloy 693, is a newly identified ‘high-temperature corrosion resistant alloy’. Present study focuses on microstructure and mechanical properties of the alloy prepared by double ‘vacuum melting’ route. In general, the alloy contains ordered Ni{sub 3}Al precipitates distributed within austenitic matrix. M{sub 6}C primary carbide, M{sub 23}C{sub 6} type secondary carbide and NbC particles are also found to be present. Heat treatment of the alloy at 1373 K for 30 min followed by water quenching (WQ) brings about a microstructure that is free from secondary carbides and Ni{sub 3}Al type precipitates but contains primary carbides. Tensile property of Alloy 693 materials was measured with as received and solution annealed (1323 K, 60 min, WQ) and (1373 K, 30 min, WQ) conditions. Yield strength, ultimate tensile strength (UTS) and hardness of the alloy are found to drop with annealing. It is noted that in annealed condition, considerable cold working of the alloy can be performed.

  2. Ni{sub 3}Al aluminide alloys

    Energy Technology Data Exchange (ETDEWEB)

    Liu, C.T.


    This paper provides a brief review of the recent progress in research and development of Ni{sub 3}Al and its alloys. Emphasis has been placed on understanding low ductility and brittle fracture of Ni{sub 3}Al alloys at ambient and elevated temperatures. Recent studies have resulted in identifying both intrinsic and extrinsic factors governing the fracture behavior of Ni{sub 3}Al alloys. Parallel efforts on alloy design using physical metallurgy principles have led to properties for structural use. Industrial interest in these alloys is high, and examples of industrial involvement in processing and utilization of these alloys are briefly mentioned.

  3. Effect of alloy elements on the anti-corrosion properties of low alloy ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 23; Issue 3. Effect of alloy elements on the anti-corrosion properties of low alloy steel ... Effect of alloy elements on corrosion of low alloy steel was studied under simulated offshore conditions. The results showed that the elements Cu, P, Mo, W, V had evident effect on ...

  4. High strength forgeable tantalum base alloy (United States)

    Buckman, R. W., Jr.


    Increasing tungsten content of tantalum base alloy to 12-15% level will improve high temperature creep properties of existing tantalum base alloys while retaining their excellent fabrication and welding characteristics.

  5. Compensative alloying of Cr-Si low-alloyed steels

    Energy Technology Data Exchange (ETDEWEB)

    Lunika, M., E-mail: [Institute of Applied Physics, National Academy of Science of Ukraine, 58, Petropavlovskaja Str., 40030 Sumy (Ukraine)


    The principle of choosing alloy elements in order to suppress the embrittlement of solid solution strengthening is proposed. In the case of Cr-Si low-alloyed steels, the effects of compensative alloying are studied. The ultimate tensile strength and impact toughness of Cr-Si steels microalloyed with Mo, V, and Ti are determined to prove the aspects. The structure of these steels is studied using optical and transmission electron microscopy techniques after applying the optimum heat treatment. The kinetics of phase transformation after quenching and tempering have been examined by means of measurements of specific electrical resistance and magnetic parameters. It is shown that at the Si-content of about 1 wt% high values of tensile strength and impact toughness are simultaneously obtained. It is established by calculations that, for the indicated steel, long-range distortions of the crystal lattice become close to zero at the Si-content of about 1 wt%.

  6. Thermomechanical behavior of comercial yellow gold alloy

    Directory of Open Access Journals (Sweden)

    Miloš G. Djordjević


    Full Text Available With the development of science and technology, in the late 19th century, began the research and application of new alloys for making jewelry. By adding different amounts of Cu and Ag alloy of Au, as well as adding some new elements (Zn, alloys were obtained with different color spectrum (from red to yellow and different technological and metallurgical characteristics. This paper aims to show thermomechanical behavior of commercial yellow Au alloys for making jewelry.

  7. Nickel aluminide alloys with improved weldability (United States)

    Santella, M.L.; Goodwin, G.M.


    Weldable nickel aluminide alloys which are essentially free, if not entirely free, of weld hot cracking are provided by employing zirconium concentrations in these alloys of greater than 2.6 wt. % or sufficient to provide a substantial presence of Ni--Zr eutectic phase in the weld so as to prevent weld hot cracking. Weld filler metals formed from these so modified nickel aluminide alloys provide for crack-free welds in previously known nickel aluminide alloys. 5 figs.

  8. Microstructural and technological optimisation of magnesium alloys


    Facchinelli, Nicola


    Magnesium is one of the most abundance element in nature, and it's characterised by a lower density than aluminium. These characteristics confer great potential to magnesium alloys, which are so used for specialised applications, like for military purposes and in the aerospace industry. While some magnesium alloys, including the AM60B alloy, are historically associated to high pressure die casting, for such applications the magnesium alloy components are usually produced by the gravity castin...

  9. New Theoretical Technique for Alloy Design (United States)

    Ferrante, John


    During the last 2 years, there has been a breakthrough in alloy design at the NASA Lewis Research Center. A new semi-empirical theoretical technique for alloys, the BFS Theory (Bozzolo, Ferrante, and Smith), has been used to design alloys on a computer. BFS was used, along with Monte Carlo techniques, to predict the phases of ternary alloys of NiAl with Ti or Cr additions. High concentrations of each additive were used to demonstrate the resulting structures.

  10. Nano-sized Superlattice Clusters Created by Oxygen Ordering in Mechanically Alloyed Fe Alloys


    Yong-Jie Hu; Jing Li; Kristopher A. Darling; William Y. Wang; VanLeeuwen, Brian K.; Xuan L Liu; Kecskes, Laszlo J.; Dickey, Elizabeth C.; Zi-Kui Liu


    Creating and maintaining precipitates coherent with the host matrix, under service conditions is one of the most effective approaches for successful development of alloys for high temperature applications; prominent examples include Ni- and Co-based superalloys and Al alloys. While ferritic alloys are among the most important structural engineering alloys in our society, no reliable coherent precipitates stable at high temperatures have been found for these alloys. Here we report discovery of...


    Moore, R.H.


    A process is given for preparing uranium--aluminum alloys from a solution of uranium halide in an about equimolar molten alkali metal halide-- aluminum halide mixture and excess aluminum. The uranium halide is reduced and the uranium is alloyed with the excess aluminum. The alloy and salt are separated from each other. (AEC)

  12. Corrosion Behaviour of New Zr Alloys

    DEFF Research Database (Denmark)

    Tolksdorf, E.


    Corrosion studies have indicated that the most promising replacements for Zicaloy-2 are ZrCrFe, ZrVFe and probably ZrNbTa, provided they are in their optimized condition. These alloys are conventionally manufactured alloys. An internally oxidized ZrMgO alloy is even superior, from the corrosion...

  13. [Microbiological corrosion of aluminum alloys]. (United States)

    Smirnov, V F; Belov, D V; Sokolova, T N; Kuzina, O V; Kartashov, V R


    Biological corrosion of ADO quality aluminum and aluminum-based construction materials (alloys V65, D16, and D16T) was studied. Thirteen microscopic fungus species and six bacterial species proved to be able to attack aluminum and its alloys. It was found that biocorrosion of metals by microscopic fungi and bacteria was mediated by certain exometabolites. Experiments on biocorrosion of the materials by the microscopic fungus Alternaria alternata, the most active biodegrader, demonstrated that the micromycete attack started with the appearance of exudate with pH 8-9 on end faces of the samples.

  14. Dendritic solidification in binary alloys (United States)

    Chopra, M. A.; Glicksman, M. E.; Singh, N. B.


    Alloys generally solidify dendritically, and associated with that is the microsegregation of impurities. Pure metals also solidify in dendritic form as 'thermal' dendrites, which actually segregate the system's enthalpy. In this investigation, small additions of solute to succinonitrile have been studied and dendritic growth observed in a supercooled melt. This free dendritic growth-mode is similar to that experienced by equiaxed dendrites found in alloy castings. Observations of these free dendrites include measurement of velocity and tip radius of the dendrites at different supercoolings and solute concentrations.


    African Journals Online (AJOL)


    Abstract. Ti-Mo alloy containing Nb and Sn were arc melted and composition analyzed by EDX. The XRD analysis indicates that the crystal structure and mechanical properties are sensitive to Sn concentration. A combination of Sn and Nb elements in synergy hindered formation athermal ω phase and significantly.

  16. An introduction to surface alloying of metals

    CERN Document Server

    Hosmani, Santosh S; Goyal, Rajendra Kumar


    An Introduction to Surface Alloying of Metals aims to serve as a primer to the basic aspects of surface alloying of metals. The book serves to elucidate fundamentals of surface modification and their engineering applications. The book starts with basics of surface alloying and goes on to cover key surface alloying methods, such as carburizing, nitriding, chromizing, duplex treatment, and the characterization of surface layers. The book will prove useful to students at both the undergraduate and graduate levels, as also to researchers and practitioners looking for a quick introduction to surface alloying.


    Gilliland, R.G.; Patriarca, P.; Slaughter, G.M.; Williams, L.C.


    A new and improved ternary alloy is described which is of particular utility in braze-bonding parts made of a refractory metal selected from Group IV, V, and VI of the periodic table and alloys containing said metal as a predominating alloying ingredient. The brazing alloy contains, by weight, 40 to 50 per cent zirconium, 40 to 50 per cent titanium, and the balance beryllium in amounts ranging from 1 to 20 per cent, said alloy having a melting point in the range 950 to 1400 deg C. (AEC)

  18. Assessment of Co-Ga alloys magnetostriction (United States)

    Bormio-Nunes, Cristina; Boccia, Daniel Lourenço Rodrigues; Fulop, Guilherme Origo; Sato-Turtelli, Reiko


    The magnetostriction of Co-Ga alloys: Co-14Ga, Co-24Ga and Co-33Ga (atomic), is studied at room temperature for the first time. All three alloys are ferromagnetic. Co-14Ga microstructure is biphasic, a mixture of ε (hcp) and α (fcc) phases. Co-24Ga presents three phases ε, α and β (ordered bcc) and Co-33Ga is single β phase alloy. It was found that all three alloys present negative saturation magnetostriction λs. The most interesting material for applications would be the alloy Co-33Ga since the magnetostriction saturates for a small field.

  19. Optical Characterization of AlAsSb Digital Alloy and Random Alloy on GaSb

    Directory of Open Access Journals (Sweden)

    Bor-Chau Juang


    Full Text Available III-(As, Sb alloys are building blocks for various advanced optoelectronic devices, but the growth of their ternary or quaternary materials are commonly limited by spontaneous formation of clusters and phase separations during alloying. Recently, digital alloy growth by molecular beam epitaxy has been widely adopted in preference to conventional random alloy growth because of the extra degree of control offered by the ordered alloying. In this article, we provide a comparative study of the optical characteristics of AlAsSb alloys grown lattice-matched to GaSb using both techniques. The sample grown by digital alloy technique showed stronger photoluminescence intensity, narrower peak linewidth, and larger carrier activation energy than the random alloy technique, indicating an improved optical quality with lower density of non-radiative recombination centers. In addition, a relatively long carrier lifetime was observed from the digital alloy sample, consistent with the results obtained from the photoluminescence study.

  20. Aeronautical Industry Requirements for Titanium Alloys (United States)

    Bran, D. T.; Elefterie, C. F.; Ghiban, B.


    The project presents the requirements imposed for aviation components made from Titanium based alloys. A significant portion of the aircraft pylons are manufactured from Titanium alloys. Strength, weight, and reliability are the primary factors to consider in aircraft structures. These factors determine the requirements to be met by any material used to construct or repair the aircraft. Many forces and structural stresses act on an aircraft when it is flying and when it is static and this thesis describes environmental factors, conditions of external aggression, mechanical characteristics and loadings that must be satisfied simultaneously by a Ti-based alloy, compared to other classes of aviation alloys (as egg. Inconel super alloys, Aluminum alloys).For this alloy class, the requirements are regarding strength to weight ratio, reliability, corrosion resistance, thermal expansion and so on. These characteristics additionally continue to provide new opportunities for advanced manufacturing methods.

  1. Aqueous recovery of actinides from aluminum alloys

    Energy Technology Data Exchange (ETDEWEB)

    Gray, J.H.; Chostner, D.F.; Gray, L.W.


    Early in the 1980's, a joint Rocky Flats/Savannah River program was established to recover actinides from scraps and residues generated during Rocky Flats purification operations. The initial program involved pyrochemical treatment of Molten Salt Extraction (MSE) chloride salts and Electrorefining (ER) anode heel metal to form aluminum alloys suitable for aqueous processing at Savannah River. Recently Rocky Flats has expressed interest in expanding the aluminum alloy program to include treatment of chloride salt residues from a modified Molten Salt Extraction process and from the Electrorefining purification operations. Samples of the current aluminum alloy buttons were prepared at Rocky Flats and sent to Savannah River Laboratory for flowsheet development and characterization of the alloys. A summary of the scrub alloy-anode heel alloy program will be presented along with recent results from aqueous dissolution studies of the new aluminum alloys. 2 figs., 4 tabs.

  2. [Fatigue properties of dental alloys. 12% Au-Pd-Ag alloy and type III gold alloy]. (United States)

    Kato, H


    Usually the mechanical properties of dental alloys are determined from the values obtained through static tests of their tensile strength, hardness, etc. Generally, high tensile strength and ductility are preferred. However, when small stresses within proportional limits are applied repeatedly (even though not amounting to destructive forces in static tests), they may cause rupture in the alloy or, at least, cause it to lose its original mechanical properties. This phenomenon is called metal fatigue. It is estimated that the intraoral stress loads received by dental restorations during mastication or during insertion and removal of appliances are repeated more than 3 x 10(5) times/year. From this standpoint, it may be more appropriate to estimate the fracture strength of such dental alloys based on the fatigue properties of the restorative materials used for clasps, bars, and fixed bridges. For this reason, it is necessary to obtain data through fatigue tests on the fatigue strength and the fatigue endurance limits of dental alloys, and it is important to find a correlation between these data and the static data on tensile strengths and ductility obtained by tensile tests. Two alloys are used in these experiments. Both wrought specimens and cast specimens of 12% Au-Pd-Ag and Type III gold alloy were prepared for the fatigue tests. The size of the rectangular wrought specimens was 3 x 4 x 110 mm. The 12% Au-Pd-Ag alloy was heated to 800 degrees C for 15 minutes, quenched, and reheated to 400 degrees C for 20 minutes and quenched again according to the manufacturer's instructions for heat treatment. The Type III gold alloy was heated to 700 degrees C for 10 minutes, quenched, and reheated to 350 degrees C for 20 minutes and quenched again. The cylindrical cast specimens were 60 mm long and 2 mm in diameter. They were invested by conventional methods and cast in a centrifugal casting machine, Thermotrol Model 2500. The four point bending test for the wrought specimen

  3. Nickel, cobalt, and their alloys

    CERN Document Server


    This book is a comprehensive guide to the compositions, properties, processing, performance, and applications of nickel, cobalt, and their alloys. It includes all of the essential information contained in the ASM Handbook series, as well as new or updated coverage in many areas in the nickel, cobalt, and related industries.

  4. Hydrostatic extrusion of magnesium alloys

    NARCIS (Netherlands)

    Sillekens, W.H.; Bohlen, J.


    This chapter deals with the capabilities and limitations of the hydrostatic extrusion process for the manufacturing of magnesium alloy sections. Firstly, the process basics for the hydrostatic extrusion of materials in general and of magnesium in particular are introduced. Next, some recent research


    Directory of Open Access Journals (Sweden)

    A. G. Slutsky


    Full Text Available Motor is one of most important part of automobile determine its economical effectiveness of usage. On the other hand, sleeves, pistons and rings are crucible parts as they determine the service life of a motor. These parts are producing in big scale – dozens of millions pieces. Increase of cylinder sleeves physical-mechanical properties results in prolongation of motor service life and improvement of motor’s characteristics. Nowadays low alloyed cast irons with perlite structure are used to manufacture motor’s sleeves. For alloying purposes such traditional elements as Cr, Ni, Cu, and V are applied. But it is interesting to use molybdenum for cast iron alloying. It is known that alloying of alloys allows considerable increasing of consumption properties of castings. But in spite of advantages of alloys alloying the increase of molybdenum containing iron-carbon alloys production is restricted by economical reasons – high cost of alloying additions. Expenditures on alloying additions can be reduced by the application cheap secondary alloys in the charge. So, the present paper is devoted to investigation of alloying peculiarities during the treatment of ferrous alloys with molybdenum applying different initial materials.

  6. The Examination of the Aluminum Alloy 7017 as a Replacement for the Aluminum Alloy 7039 in Lightweight Armor Systems (United States)


    Aluminum Alloy 7017 as a Replacement for the Aluminum ...2016 US Army Research Laboratory The Examination of the Aluminum Alloy 7017 as a Replacement for the Aluminum Alloy 7039 in Lightweight Armor... Aluminum Alloy 7017 as a Replacement for the Aluminum Alloy 7039 in Lightweight Armor Systems 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c.

  7. Status of Testing and Characterization of CMS Alloy 617 and Alloy 230

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Weiju [ORNL; Santella, Michael L [ORNL; Battiste, Rick [ORNL; Terry, Totemeier [Idaho National Laboratory (INL); Denis, Clark [Idaho National Laboratory (INL)


    Status and progress in testing and characterizing CMS Alloy 617 and Alloy 230 tasks in FY06 at ORNL and INL are described. ORNL research has focused on CMS Alloy 617 development and creep and tensile properties of both alloys. In addition to refurbishing facilities to conduct tests, a significant amount of creep and tensile data on Alloy 230, worth several years of research funds and time, has been located and collected from private enterprise. INL research has focused on the creep-fatigue behavior of standard chemistry Alloy 617 base metal and fusion weldments. Creep-fatigue tests have been performed in air, vacuum, and purified Ar environments at 800 and 1000 C. Initial characterization and high-temperature joining work has also been performed on Alloy 230 and CCA Alloy 617 in preparation for creep-fatigue testing.

  8. Effects of segregation of primary alloying elements on the creep response in magnesium alloys

    DEFF Research Database (Denmark)

    Huang, Y.D.; Dieringa, H.; Hort, N.


    The segregation of primary alloying elements deteriorates the high temperature creep resistance of magnesium alloys. Annealing at high temperatures alleviating their segregations can improve the creep resistance. Present investigation on the effect of segregation of primary alloying elements...... on the creep response may provide some useful information about how to improve the creep resistance of magnesium alloys in the future. (c) 2008 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved....

  9. The Influence of Novel Alloying Additions on the Performance of Magnesium Alloy AZ31B (United States)


    alloys are based on a rather small group of alloying elements, there are often limited differences between them in properties (strength, corrosion...the first year of the project. 2. Introduction To date, the majority of Mg alloys have used a rather small group of alloying elements (such as...and subsequently processed using Equal Channel Angular Extrusion ( ECAE ) in an attempt to obtain ultra-fine-grained samples. Detailed evaluation of

  10. Bulk amorphous Mg-based alloys

    DEFF Research Database (Denmark)

    Pryds, Nini


    and a low glass transition temperature. The alloys were prepared by using a relatively simple technique, i.e. rapid cooling of the melt in a copper wedge mould. The essential structural changes that are achieved by going from the amorphous to the crystalline state through the supercooled liquid state...... are discussed in this paper. On the basis of these measurements phase diagrams of the different systems were constructed. Finally, it is demonstrated that when pressing the bulk amorphous alloy onto a metallic dies at temperatures within the supercooled liquid region, the alloy faithfully replicates the surface......The present paper describes the preparation and properties of bulk amorphous quarternary Mg-based alloys and the influence of additional elements on the ability of the alloy to form bulk amorphous. The main goal is to find a Mg-based alloy system which shows both high strength to weight ratio...

  11. Theory of Random Anisotropic Magnetic Alloys

    DEFF Research Database (Denmark)

    Lindgård, Per-Anker


    A mean-field-crystal-field theory is developed for random, multicomponent, anisotropic magnetic alloys. It is specially applicable to rare-earth alloys. A discussion is given of multicritical points and phase transitions between various states characterized by order parameters with different...... spatial directions or different ordering wave vectors. Theoretical predictions based on known parameters for the phase diagrams and magnetic moments for the binary rare-earth alloys of Tb, Dy, Ho, and Er, Tb-Tm, Nd-Pr, and pure double-hcp Nd agree qualitatively with the experimental observations....... Quantitative agreement can be obtained by increasing the interaction between different alloy elements, in particular for alloys with very different axial anisotropy, e.g., Tb-Tm. A model system consisting of a singlet-singlet and singlet-doublet alloy is discussed in detail. A simple procedure to include...

  12. Magnetism of quaternary Heusler alloys

    Energy Technology Data Exchange (ETDEWEB)

    Kudrnovsky, Josef; Drchal, Vaclav [Institute of Physics, AS CR, Prague (Czech Republic); Bose, Shyamal [Brock University, St. Catharines (Canada); Turek, Ilja [Institute of Physics of Materials, AS CR, Brno (Czech Republic)


    The electronic properties, exchange interactions, finite-temperature magnetism and transport properties of random Ni{sub 2}MnSn quaternary Heusler alloys doped with Cu- and Pd-atoms are studied theoretically by means of first-principles calculations over the entire concentration range. While the magnetic moments are only weakly dependent on the alloy composition, the Curie temperatures exhibit strongly non-linear behavior with respect to Cu-doping in contrast with an almost linear concentration dependence in the case of Pd-doping. The residual resistivity obey the Nordheim rule while the dominating contribution to the temperature-dependent resistivity is due to thermodynamical fluctuations originating from the spin-disorder, which, according to our calculations, can be described reasonably well via the disordered local moments model. The present parameter-free theory agrees qualitatively and also reasonably well quantitatively with all available experiments.

  13. Digital Alloy Absorber for Photodetectors (United States)

    Hill, Cory J. (Inventor); Ting, David Z. (Inventor); Gunapala, Sarath D. (Inventor)


    In order to increase the spectral response range and improve the mobility of the photo-generated carriers (e.g. in an nBn photodetector), a digital alloy absorber may be employed by embedding one (or fraction thereof) to several monolayers of a semiconductor material (insert layers) periodically into a different host semiconductor material of the absorber layer. The semiconductor material of the insert layer and the host semiconductor materials may have lattice constants that are substantially mismatched. For example, this may performed by periodically embedding monolayers of InSb into an InAsSb host as the absorption region to extend the cutoff wavelength of InAsSb photodetectors, such as InAsSb based nBn devices. The described technique allows for simultaneous control of alloy composition and net strain, which are both key parameters for the photodetector operation.


    Moore, R.H.


    BS>A process is given for preparing alloys of aluminum with plutonium, uranium, and/or thorium by chlorinating actinide oxide dissolved in molten alkali metal chloride with hydrochloric acid, chlorine, and/or phosgene, adding aluminum metal, and passing air and/or water vapor through the mass. Actinide metal is formed and alloyed with the aluminum. After cooling to solidification, the alloy is separated from the salt. (AEC)

  15. Aspects of precipitation in alloy Inconel 718


    Azadian, Saied


    A study was made of the microstructure of the Ni-base alloy Inconel 718 with emphasis on the precipitation and stability of intermetallic phases as affected by heat treatments. In addition the effect of the precipitation on selected mechanical properties namely hardness, creep notch sensitivity and hot ductlity were investigated. The materials studied were a spray-formed version and three wrought versions of the alloy. The spray-formed version of the alloy was of interest since it exhibited a...

  16. Research and Development on Titanium Alloys (United States)


    61 No. 733 LWE: ec/mk/ma September 14, 1949 13ATTK- LLE MESMORIAL INSTITUTE DEPARTMENT OF THE AIR FORCE HEADOUARTERS AERONAUTICAL SYSTEMS CENTER (AFMC...period reported, titanium binary alloys of germanium and nickel vere studied, as venl as tltanium-molybdenum and titanium- manganese ternary alloys. Carbon...September 18, 1949, titanium binary alloys of germanium and nickel were studied. Also investigated were titanium-molybdenum and titanium-manganese ternary

  17. Low-Gold-Content Brazing Alloys (United States)

    Brennan, A.; Mckown, R. D.


    Two new alloys for brazing at 1,760 degrees to 1,850 degrees F are stronger and have better gap-filling capability. Alloys have lower gold content than other gold brazes for their temperature range and therefore are far less expensive. They are produced in wire, foil, and powder and are excellent for brazing at temperatures where no suitable alloys existed--especially for step brazing copper.

  18. Alloy nanoparticle synthesis using ionizing radiation (United States)

    Nenoff, Tina M [Sandia Park, NM; Powers, Dana A [Albuquerque, NM; Zhang, Zhenyuan [Durham, NC


    A method of forming stable nanoparticles comprising substantially uniform alloys of metals. A high dose of ionizing radiation is used to generate high concentrations of solvated electrons and optionally radical reducing species that rapidly reduce a mixture of metal ion source species to form alloy nanoparticles. The method can make uniform alloy nanoparticles from normally immiscible metals by overcoming the thermodynamic limitations that would preferentially produce core-shell nanoparticles.

  19. Advanced powder metallurgy aluminum alloys and composites (United States)

    Lisagor, W. B.; Stein, B. A.


    The differences between powder and ingot metallurgy processing of aluminum alloys are outlined. The potential payoff in the use of advanced powder metallurgy (PM) aluminum alloys in future transport aircraft is indicated. The national program to bring this technology to commercial fruition and the NASA Langley Research Center role in this program are briefly outlined. Some initial results of research in 2000-series PM alloys and composites that highlight the property improvements possible are given.

  20. Deformation Driven Alloying and Transformation (United States)


    1991;15:317. [69] Watson A, Hayes F. J Alloys Compd 2001;320:199. [70] Ohtake M, Nonaka Y, Futamoto M. IEEE Trans Magn 2012;48:1589. [71] Heinrich B...Hahn H, Averback R, Bellon P. Phys.Rev. B 2012;86:144302. [77] Bellon P, Averback RS. Phys. Rev. Lett. 1995;74:1819. 28 [78] Takeuchi A, Inoue

  1. Brazing Alloys Indicate Turbomachinery Temperatures (United States)

    Schlaff, J. W.


    Foils serve as consumable thermometers. Stainless-steel tab with circular window holds brazing-foil sample in place. Tab tacked to object to be tested with capacitive-discharge spot welder operating in range 10 + 1 joules. After measurements, tabs and samples chiseled off, leaving tested object fairly well intact. Technique used on objects made of alloys with iron, nickel, or cobalt as principal ingredients.

  2. Electrodeposition of engineering alloy coatings

    DEFF Research Database (Denmark)

    Christoffersen, Lasse

    Nickel based electrodeposited alloys were investigated with respect to their deposition process, heat treatment, hardness, corrosion resistance and combined wear-corrosion resistance. The investigated alloys were Ni-B, Ni-P and Ni-W, which are not fully developed for industrial utilisation...... are written in brackets). Temperature and especially pH influenced the cathodic efficiency of the electrodeposition processes for Ni-W and Ni-P. Mass balance problems of the development alloy processes are identified.Heat treatment for one hour at approx. 350°C, 400°C and 600°C of electrodeposited Ni-B, Ni......-P and Ni-W, respectively, resulted in hardness values of approx. 1000 HV0.1 in the case of Ni-P(6), approx. 1100 HV0.1 in the case of Ni-W(40-53) and approx. 1300 HV0.1 in the case of Ni-B(5). Cracks, which emerged during electrodeposition and heat treatment, were observed on Ni-W and Ni-B.The corrosion...

  3. Pack cementation coatings for alloys

    Energy Technology Data Exchange (ETDEWEB)

    He, Yi-Rong; Zheng, Minhui; Rapp, R.A. [Ohio State Univ., Columbus, OH (United States)


    The halide-activated pack cementation process was modified to produce a Ge-doped silicide diffusion coating on a Cr-Cr{sub 2}Nb alloy in a single processing step. The morphology and composition of the coating depended both on the composition of the pack and on the composition and microstructure of the substrate. Higher Ge content in the pack suppressed the formation of CrSi{sub 2} and reduced the growth kinetics of the coating. Ge was not homogeneously distributed in the coatings. In cyclic and isothermal oxidation in air at 700 and 1050{degrees}C, the Ge-doped silicide coating protected the Cr-Nb alloys from significant oxidation by the formation of a Ge-doped silica film. The codeposition and diffusion of aluminum and chromium into low alloy steel have been achieved using elemental Al and Cr powders and a two-step pack cementation process. Sequential process treatments at 925{degrees}C and 1150{degrees}C yield dense and uniform ferrite coatings, whose compositions are close to either Fe{sub 3}Al or else FeAl plus a lower Cr content, when processed under different conditions. The higher content of Al in the coatings was predicted by thermodynamic calculations of equilibrium in the gas phase. The effect of the particle size of the metal powders on the surface composition of the coating has been studied for various combinations of Al and Cr powders.

  4. Mechanically alloyed aluminum metal matrix composites (United States)

    Hashiguchi, Don; Tricker, David; Tarrant, Andrew


    Aluminum alloys reinforced with ceramic particles produce a low density metal matrix composite (MMC) with enhanced mechanical and physical properties including relatively high modulus and vibration loss. This paper will outline the capability through Powder Metallurgy processing techniques made by mechanical alloying (MA). MA enables production of MMC's with micron to submicron mean particulate reinforcement size which increases mechanical properties in comparison to larger reinforcement particle size. Smaller reinforcement particles also result in a material that fits well within established value streams enabling conventional post consolidation metalworking and machining methods. The microstructure and properties of MMC's mechanical alloyed with base aluminum alloys 6061B and 2124A will be presented.

  5. Titanium alloys Russian aircraft and aerospace applications

    CERN Document Server

    Moiseyev, Valentin N


    This text offers previously elusive information on state-of-the-art Russian metallurgic technology of titanium alloys. It details their physical, mechanical, and technological properties, as well as treatments and applications in various branches of modern industry, particularly aircraft and aerospace construction. Titanium Alloys: Russian Aircraft and Aerospace Applications addresses all facets of titanium alloys in aerospace and aviation technology, including specific applications, fundamentals, composition, and properties of commercial alloys. It is useful for all students and researchers interested in the investigation and applications of titanium.

  6. Casting Characteristics of Aluminum Die Casting Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Makhlouf M. Makhlouf; Diran Apelian


    The research program investigates the casting characteristics of selected aluminum die casting alloys. Specifically, the alloys' tendencies towards die soldering and sludge formation, and the alloys' fluidity and machinability are evaluated. It was found that: When the Fe and Mn contents of the alloy are low; caution has to be taken against possible die soldering. When the alloy has a high sludge factor, particularly a high level of Fe, measures must be taken to prevent the formation of large hardspots. For this kind of alloy, the Fe content should be kept at its lowest allowable level and the Mn content should be at its highest possible level. If there are problems in die filling, measures other than changing the alloy chemistry need to be considered first. In terms of alloy chemistry, the elements that form high temperature compounds must be kept at their lowest allowable levels. The alloys should not have machining problems when appropriate machining techniques and machining parameters are used.

  7. Barocaloric effect in metamagnetic shape memory alloys

    Energy Technology Data Exchange (ETDEWEB)

    Manosa, Lluis; Stern-Taulats, Enric; Planes, Antoni [Facultat de Fisica, Departament d' Estructura i Constituents de la Materia, Universitat de Barcelona (Spain); Lloveras, Pol; Barrio, Maria; Tamarit, Josep-Lluis [Departament de Fisica i Enginyeria Nuclear, ETSEIB, Universitat Politecnica de Catalunya, Barcelona (Spain); Emre, Baris [Faculty of Engineering, Department of Engineering Physics, Ankara University (Turkey); Yuece, Suheyla [Department of Physics, Science and Literature Faculty, Ondokuz Mayis University, Samsun (Turkey); Fabbrici, Simone [MIST E-R Laboratory, Bologna (Italy); IMEM-CNR, Parma (Italy); Albertini, Franca [IMEM-CNR, Parma (Italy)


    We report on calorimetric measurements under hydrostatic pressure in a series of composition related metamagnetic shape memory alloys. We show that metamagnetic shape memory alloys exhibit a barocaloric effect whose magnitude compares well to the magnetocaloric effect exhibited by this kind of alloys. While in metamagnetic alloys the magnetocaloric effect is inverse, the barocaloric effect has been found to be conventional. The values obtained for the pressure-induced entropy changes at moderate pressures are in the range of those reported for giant caloric materials. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. Thermally activated martensite formation in ferrous alloys

    DEFF Research Database (Denmark)

    Villa, Matteo; Somers, Marcel A. J.


    Magnetometry was applied to investigate the formation of α/α´martensite in 13ferrous alloys during immersion in boiling nitrogen and during re-heating to room temperature at controlled heating rates in the range 0.0083-0.83 K s-1. Data showsthat in 3 of the alloys, those that form {5 5 7}γ...... martensite, no martensite developsduring cooling. For all investigated alloys, irrespective of the type of martensiteforming, thermally activated martensite develops during heating. The activationenergy for thermally activated martensite formation is in the range 8‒27 kJ mol-1and increases with the fraction...... of interstitial solutes in the alloy...

  9. Preparation of superconducting Nb-Zr alloys

    Energy Technology Data Exchange (ETDEWEB)

    Drapala, J.; Kuchar, L. (Vysoka Skola Banska, Ostrava (Czechoslovakia). Katedra Nezeleznych Kovu a Jaderne Metalurgie)


    Superconducting Nb-Zr alloy with a zirconium content of up to 3 wt.% was prepared by a combination of arc and electron zone melting. First, the Nb-Zr master alloy with 1 wt.% Zr was prepared in a horizontal arc furnace under an argon atmosphere. This master alloy was remelted several times to achieve the highest possible homogeneity of samples. The Nb-Zr ingot was then remelted through two zone passes on equipment for high-vacuum electron zone melting. Samples were taken of the Nb-Zr alloy and a metallographic analysis was made.

  10. Investigations on the optimization of phase and alloy compositions of Al-Cu-Si-Mg alloys

    Energy Technology Data Exchange (ETDEWEB)

    Eskin, D.G. (A.A. Baikov Inst. of Metallurgy, Russian Academy of Sciences, Moscow (Russia))


    The effect of the supersaturated solid solution composition on the phase composition of aging products in Al - (4 mass%) Cu-Si-Mg alloys has been investigated in a broad compositional range. The diagram of distribution of phase regions has been constructed for the Al-Cu (4 mass%)-Si-Mg alloys after aging at 170degC for 20 h. With cast and deformed alloys, it has been shown exemplarily that the best complex of mechanical properties is associated with alloy compositions ensuring the precipitation of [Theta]' and [beta]'' phases. The composition of cast Al - Si - Cu - Mg alloys has been optimized. (orig.).

  11. Bond Strength of Gold Alloys Laser Welded to Cobalt-Chromium Alloy


    Watanabe, Ikuya; Wallace, Cameron


    The objective of this study was to investigate the joint properties between cast gold alloys and Co-Cr alloy laser-welded by Nd:YAG laser. Cast plates were fabricated from three types of gold alloys (Type IV, Type II and low-gold) and a Co-Cr alloy. Each gold alloy was laser-welded to Co-Cr using a dental laser-welding machine. Homogeneously-welded and non-welded control specimens were also prepared. Tensile testing was conducted and data were statistically analyzed using ANOVA. The homogeneo...

  12. Data set for diffusion coefficients of alloying elements in dilute Mg alloys from first-principles

    Directory of Open Access Journals (Sweden)

    Bi-Cheng Zhou


    Full Text Available Diffusion coefficients of alloying elements in Mg are critical for the development of new Mg alloys for lightweight applications. Here we present the data set of the temperature-dependent dilute tracer diffusion coefficients for 47 substitutional alloying elements in hexagonal closed packed (hcp Mg calculated from first-principles calculations based on density functional theory (DFT by combining transition state theory and an 8-frequency model. Benchmark for the DFT calculations and systematic comparison with experimental diffusion data are also presented. The data set refers to “Diffusion coefficients of alloying elements in dilute Mg alloys: A comprehensive first-principles study” by Zhou et al. [1].

  13. Development of a Brazing Alloy for the Mechanically Alloyed High Temperature Sheet Material INCOLOY Alloy MA 956. (United States)


    OF CONTENTS Section Pge 1. INTRODUCTION AND PW)GRAM E OBJECTIVE 7 2. ALLOYING APROACH AND RATIONALE 9 2.1 Approach 9 2.2 Selection of Suitable Alloy...At the time of writing this final summary report only limited success has been achieved by Allied Chemicals but it is reported as follows so that the

  14. Role of alloying elements in adhesive transfer and friction of copper-base alloys (United States)

    Buckley, D. H.


    Sliding friction experiments were conducted in a vacuum with binary-copper alloy riders sliding against a conventional bearing-steel surface with normal residual oxides present. The binary alloys contained 1 atomic percent of various alloying elements. Auger spectroscopy analysis was used to monitor the adhesive transfer of the copper alloys to the bearing-steel surface. A relation was found to exist between adhesive transfer and the reaction potential and free energy of formation of the alloying element in the copper. The more chemically active the element and the more stable its oxide, the greater was the adhesive transfer and wear of the copper alloy. Transfer occurred in all the alloys except copper-gold after relatively few (25) passes across the steel surface.

  15. Bond strength of gold alloys laser welded to cobalt-chromium alloy. (United States)

    Watanabe, Ikuya; Wallace, Cameron


    The objective of this study was to investigate the joint properties between cast gold alloys and Co-Cr alloy laser-welded by Nd:YAG laser. Cast plates were fabricated from three types of gold alloys (Type IV, Type II and low-gold) and a Co-Cr alloy. Each gold alloy was laser-welded to Co-Cr using a dental laser-welding machine. Homogeneously-welded and non-welded control specimens were also prepared. Tensile testing was conducted and data were statistically analyzed using ANOVA. The homogeneously-welded groups showed inferior fracture load compared to corresponding control groups, except for Co-Cr. In the specimens welded heterogeneously to Co-Cr, Type IV was the greatest, followed by low-gold and Type II. There was no statistical difference (Palloys tested, the Type IV gold alloy was the most suitable alloy for laser-welding to Co-Cr.

  16. The role of the alloy matrix in the creep behavior of particle-strengthened alloys (United States)

    Ajaja, O.; Howson, T. E.; Purushothaman, S.; Tien, J. K.


    The strengthening microstructural features in heat-resistant super-alloys are oxide dispersoids and/or gamma-prime precipitates. The role of the strength of the alloy matrix in the creep resistance of these alloys is considered. An evaluation was made of experimental data on oxide-dispersion- and/or precipitation-strengthened nickel-based alloys with various levels of matrix solid solution strengthening; a generalized expression for creep rates which separates the matrix contributions from the particle contributions to the resisting stress and creep strength of these alloys was derived. It is concluded that the major role of the alloy matrix in the creep behavior of these alloys is in determining the apparent stress dependence of the creep rates.

  17. Alloys of clathrate allotropes for rechargeable batteries (United States)

    Chan, Candace K; Miller, Michael A; Chan, Kwai S


    The present disclosure is directed at an electrode for a battery wherein the electrode comprises clathrate alloys of silicon, germanium or tin. In method form, the present disclosure is directed at methods of forming clathrate alloys of silicon, germanium or tin which methods lead to the formation of empty cage structures suitable for use as electrodes in rechargeable type batteries.

  18. Heat storage in alloy transformations. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Birchenall, C E; Gueceri, S I; Farkas, D; Labdon, M B; Nagaswami, N; Pregger, B


    A study conducted to determine the feasibility of using metal alloys as thermal energy storage media is described. The study had the following major elements: (1) the identification of congruently transforming alloys and thermochemical property measurements, (2) the development of a precise and convenient method for measuring volume change during phase transformation and thermal expansion coefficients, (3) the development of a numerical modeling routine for calculating heat flow in cylindrical heat exchangers containing phase-change materials, and (4) the identification of materials that could be used to contain the metal alloys. The elements selected as candidate media were limited to aluminum, copper, magnesium, silicon, zinc, calcium, and phosphorus on the basis of low cost and latent heat of transformation. Several new eutectic alloys and ternary intermetallic phases have been determined. A new method employing x-ray absorption techniques was developed to determine the coefficients of thermal expansion of both the solid and liquid phases and the volume change during phase transformation from data that are obtained during one continuous experimental test. The method and apparatus are discussed and the experimental results are presented. The development of the numerical modeling method is presented and results are discussed for both salt and metal alloy phase-change media. Candidate materials were evaluated to determine suitable materials for containment of the metal alloys. Graphite was used to contain the alloys during the volume change measurements. Silicon carbide has been identified as a promising containment material and surface-coated iron alloys were considered.

  19. Materials data handbook: Aluminum alloy 2219 (United States)

    Muraca, R. F.; Whittick, J. S.


    A summary of the materials property information for aluminum 2219 alloy is presented. The scope of the information includes physical and mechanical properties at cryogenic, ambient, and elevated temperatures. Information on material procurement, metallurgy of the alloy, corrosion, environmental effects, fabrication, and joining techniques is developed.

  20. Materials data handbook: Aluminum alloy 5456 (United States)

    Muraca, R. F.; Whittick, J. S.


    A summary of the materials property information for aluminum alloy 5456 is presented. The scope of the information includes physical and mechanical property data at cryogenic, ambient, and elevated temperatures. Information on material procurement, metallurgy of the alloy, corrosion, environmental effects, fabrication, and joining techniques is developed.

  1. Materials data handbook: Aluminum alloy 6061 (United States)

    Muraca, R. F.; Whittick, J. S.


    A summary of the materials property information for aluminum alloy 6061 is presented. The scope of the information includes physical and mechanical properties of the alloy at cryogenic, ambient, and elevated temperatures. Information on material procurement, metallurgy, corrosion, environmental effects, fabrication, and joining techniques is developed.

  2. Tantalum modified ferritic iron base alloys (United States)

    Oldrieve, R. E.; Blankenship, C. P. (Inventor)


    Strong ferritic alloys of the Fe-CR-Al type containing 0.4% to 2% tantalum were developed. These alloys have improved fabricability without sacrificing high temperature strength and oxidation resistance in the 800 C (1475 F) to 1040 C (1900 F) range.

  3. Materials data handbook: Inconel alloy 718 (United States)

    Muraca, R. F.; Whittick, J. S.


    A summary of the materials property information for Inconel alloy 718 is presented. The scope of the information includes physical and mechanical properties at cryogenic, ambient, and elevated temperatures. Information on material procurement, metallurgy of the alloy, corrosion, environmental effects, fabrication, and joining techniques is developed.

  4. Development of high performance ODS alloys

    Energy Technology Data Exchange (ETDEWEB)

    Shao, Lin; Gao, Fei; Garner, Frank


    This project aims to capitalize on insights developed from recent high-dose self-ion irradiation experiments in order to develop and test the next generation of optimized ODS alloys needed to meet the nuclear community's need for high strength, radiation-tolerant cladding and core components, especially with enhanced resistance to void swelling. Two of these insights are that ferrite grains swell earlier than tempered martensite grains, and oxide dispersions currently produced only in ferrite grains require a high level of uniformity and stability to be successful. An additional insight is that ODS particle stability is dependent on as-yet unidentified compositional combinations of dispersoid and alloy matrix, such as dispersoids are stable in MA957 to doses greater than 200 dpa but dissolve in MA956 at doses less than 200 dpa. These findings focus attention on candidate next-generation alloys which address these concerns. Collaboration with two Japanese groups provides this project with two sets of first-round candidate alloys that have already undergone extensive development and testing for unirradiated properties, but have not yet been evaluated for their irradiation performance. The first set of candidate alloys are dual phase (ferrite + martensite) ODS alloys with oxide particles uniformly distributed in both ferrite and martensite phases. The second set of candidate alloys are ODS alloys containing non-standard dispersoid compositions with controllable oxide particle sizes, phases and interfaces.

  5. Aluminum alloy nanosecond vs femtosecond laser marking

    Indian Academy of Sciences (India)

    aluminum alloy, a vastly used material base within several industry fields. For the novelty impact, femtolaser mark- ing has ... The modern industry, in order to preserve, protect, promote and enhance the value of their activities, use .... the laser beam; therefore, the freshly formed clusters of li- quid alloy microspheres have the ...

  6. Titanium and titanium alloys: fundamentals and applications

    National Research Council Canada - National Science Library

    Leyens, C; Peters, M


    ... number of titanium alloys have paved the way for light metals to vastly expand into many industrial applications. Titanium and its alloys stand out primarily due to their high specific strength and excellent corrosion resistance, at just half the weight of steels and Ni-based superalloys. This explains their early success in the aerospace and the...

  7. Methods for Electrodepositing Composition-Modulated Alloys

    DEFF Research Database (Denmark)

    Leisner, Peter; Nielsen, Christian Bergenstof; Tang, Peter Torben


    Materials exhibiting unique mechanical, physical and chemical properties can be obtained by combining thin layers of different metals or alloys forming a multilayered structure. Two general techniques exist for electrodepositing composition-modulated alloy (CMA) materials; dual-bath and single...

  8. Atomic displacements in bcc dilute alloys

    Indian Academy of Sciences (India)

    Keywords. Atomic displacements; crystal defects; crystalline solids. PACS Nos 63.43.j; 63.43.Dq; 61.66.Dk; 61.72.Ji. 1. Introduction. The transition metal dilute alloys are studied for their unique properties such as high strength ...... Even the recent techniques like EXAFS are inadequate for bcc alloys because in the EXAFS ...

  9. Inventory of alloy composition, microstructures and mechanical ...

    African Journals Online (AJOL)

    The mechanical test results show that crankshaft possesses high strength, toughness and hardness and it is case hardened alloy steel while camshaft displays excellent resistance to wear, high brittleness and it is alloy cast Iron. Results also reveal that connecting rod possesses high strength and toughness and it is ...

  10. Improving mechanical properties of aluminium alloy through ...

    African Journals Online (AJOL)

    This paper investigates the microstructure and mechanical properties of aluminum alloy (Al-Si-Fe) reinforced with coconut shell-ash particulate. The aluminium (Al-Si-Fe) alloy composite was produced by a double-stir casting process at a speed of 700 rpm for 10 and 5 minutes at first and second stirring respectively.


    Directory of Open Access Journals (Sweden)

    T.P. Pavlenko


    Full Text Available The paper reviews and analyzes properties of amorphous alloys for the purpose of their application in magnetic systems of electrical apparatus instead of high-permeability electric steels. The studies have shown a possibility of utilizing these alloys in the magnetic structure of a current transformer in the pulsed voltage stabilizer of an automated circuit-breaker semiconductor release.

  12. Progress in High-Entropy Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Michael C


    Strictly speaking, high-entropy alloys (HEAs) refer to single-phase, solid-solution alloys with multiprincipal elements in an equal or a near-equal molar ratio whose configurational entropy is tremendously high. This special topic was organized to reflect the focus and diversity of HEA research topics in the community.

  13. R-HPDC of magnesium alloys

    CSIR Research Space (South Africa)

    Curle, UA


    Full Text Available liquid segregation is observed in the as-cast microstructure for all three alloys. Minor alloy additions of Mn, in composition specifications, results in the formation of Al8Mn5 intermetallic phase particles dispersed throughout the microstructure. All...


    NARCIS (Netherlands)


    Resistivity measurements on liquid Rb-In and Cs-In alloys provide evidence for compound formation at a composition of 50% In. The discussion is based on existing electronic structure calculations for solid alloys of Li and Na with Ga, In and Tl. Several possible models for describing liquid

  15. [Corrosion resistance of Ti-Cu alloy]. (United States)

    Song, Yu-Xuan; Wang, Shi-Ming


    to investigate the corrosion behavior of Ti-Cu alloy in 0.9%NaCl solution and in acidified 0.9%NaCl solution. the microstructure of Ti-Cu alloys were characterized by means of X-ray diffraction (XRD). The electrochemical behavior of Ti-Cu alloy in two solutions (namely 0.9%NaCl solution and acidified 0.9%NaCl solution) was tested. Commercial pure Ti and 316L stainless steel were used as control. Ti-Cu alloys were composed by α-Ti and Ti(2)Cu intermetallic compound. After 3500 s immersion, the open circuit potential (OCP) values of pure Ti, Ti-5Cu alloy and Ti-10Cu alloy in 0.9% NaCl solution were -188, -181 and -173 mV, respectively. In 0.9% NaCl solution with lactic acid added, the OCP values were -143, -158 and -109 mV, respectively. In potentiodynamic polarization tests, the passive current densities of pure Ti and Ti-5Cu alloys were about 20 µA/cm(2). However, 316L stainless steel experienced pitting corrosion. it was possible to establish the following relation for their corrosion resistances: pure Ti≈Ti-5Cu > Ti-10Cu > 316L stainless steel. The addition of lactic acid in the solution did not compromise the corrosion resistance of Ti-Cu alloys.

  16. The interaction of hydrogen with metal alloys (United States)

    Danford, M. D.; Montano, J. W.


    Hydrogen diffusion coefficients were measured for several alloys, and these were determined to be about the same at 25 C for all alloys investigated. The relation of structure, both metallurgical and crystallographic, to the observed hydrogen distribution on charging was investigated, as well as the role of hydride formation in the hydrogen resistance of metal alloys. An attempt was made to correlate the structures and compositions of metal alloys as well as other parameters with the ratios of their notched tensile strengths in hydrogen to that in helium, R(H2/He), which are believed to represent a measure of their hydrogen resistance. Evidence supports the belief that hydrogen permeability and hydrogen resistance are increased by smaller grain sizes for a given alloy composition.

  17. A Study of Tungsten-Technetium Alloys (United States)

    Maltz, J. W.


    Technetium is a sister element to rhenium and has many properties that are similar to rhenium. It is predicted that technetium will have about the same effects on tungsten as rhenium in regard to increase in workability, lowered ductile to brittle transition temperature, and improved ductility. The objectives of the current work are to recover technetium from fission product wastes at Hanford Atomic Products Operation and reduce to purified metal; prepare W-Tc alloys containing up to 50 atomic% Tc; fabricate the alloy ingots to sheet stock, assessing the effect of technetium on workability; and perform metallurgical and mechanical properties evaluation of the fabricated alloys. Previous reports have described the separation and purification of 800 g of technetium metal powder, melting of technetium and W-Tc alloys, and some initial observation of the alloy material.

  18. Long - range foundry Al composite alloys

    Directory of Open Access Journals (Sweden)

    A. D. Mekhtiev


    Full Text Available The technology of obtaining nanostructural composite aluminum alloys consists in the plasma injection of refractory nanometric particles with simultaneous two-plane magnetic dynamic mixing of the melt. Particularly important in obtaining composite aluminum matrix alloys is the provision of the introduced particles wettability with the matrix melt for forming stable adhesive bonds. Nanostructured powder components can be considered not only to be a starting product for producing nanostructural composite aluminum alloys but as an independent commerce product. Nanostructural composite metal matrix alloys make one of the most prospective structural materials of the future, and liquid-phase technologies of their obtaining are the most competitive in producing products of nanostructural composite aluminum alloys in the industrial scale.

  19. Internal chlorination of Ni-Cr alloys

    Energy Technology Data Exchange (ETDEWEB)

    Berztiss, D.; Hennesen, K.; Grabke, H.J. [Max-Planck-Institut fuer Eisenforschung GmbH, Duesseldorf (Germany)


    In contrast to internal oxidation, sulfidation and carburization, very little information is available regarding internal chlorination, especially diffusion of chlorine in metallic alloys. This paper describes results of experiments on Ni-Cr alloys (<10 wt% Cr) exposed in an atmosphere containing radioactive HCl. The diffusion of chlorine in the alloy can be determined by measurement of residual {beta}-activity from the sample surface. Successively thin layers (0.5-10 {mu}m) of the alloy were removed by lapping and the surface activity was measured to obtain a depth profile. Both single and polycrystalline materials were tested. Through this work it should be determined if there is in fact solubility and diffusion of chlorine in Ni-based alloys as some authors have proposed or if the ingress of chlorine is mainly a grain boundary phenomenon. (orig.)

  20. Corrosion resistance improvement of titanium base alloys

    Directory of Open Access Journals (Sweden)

    Mihai V. Popa


    Full Text Available The corrosion resistance of the new Ti-6Al-4V-1Zr alloy in comparison with ternary Ti-6Al-4V alloy in Ringer-Brown solution and artificial Carter-Brugirard saliva of different pH values was studied. In Ringer-Brown solution, the new alloy presented an improvement of all electrochemical parameters due to the alloying with Zr; also, impedance spectra revealed better protective properties of its passive layer. In Carter-Brugirard artificial saliva, an increase of the passive film thickness was proved. Fluoride ions had a slight negative influence on the corrosion and ion release rates, without to affect the very good stability of the new Ti-6Al-4V-1Zr alloy.

  1. Magnesium and related low alloys

    Energy Technology Data Exchange (ETDEWEB)

    Bernard, J.; Caillat, R.; Darras, R. [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires


    In the first part the authors examine the comparative corrosion of commercial magnesium, of a magnesium-zirconium alloy (0,4 per cent {<=} Zr {<=} 0,7 per cent) of a ternary magnesium-zinc-zirconium alloy (0,8 per cent {<=} Zn {<=} 1,2 per cent) and of english 'Magnox type' alloys, in dry carbon dioxide-free air, in damp carbon dioxide-free air, and in dry and damp carbon dioxide, at temperatures from 300 to 600 deg. C. In the second part the structural stability of these materials is studied after annealings, of 10 to 1000 hours at 300 to 450 deg. C. Variations in grain after these heat treatments and mechanical stretching properties at room temperature are presented. Finally various creep rate and life time diagrams are given for these materials, for temperatures ranging from 300 to 450 deg. C. (author) [French] Dans une premiere partie les auteurs etudient la corrosion comparee du magnesium commercial, d'un alliage magnesium-zirconium (0,4 pour cent {<=} Zr {<=} 0,7 pour cent), d'un alliage ternaire magnesium-zinc-zirconium (0,8 pour cent {<=} Zn {<=} 1,2 pour cent), et d'alliages anglais 'type Magnox', dans l'air sec decarbonate, l'air humide decarbonate, le gaz carbonique sec et humide a des temperatures de 300 a 600 deg. C. Dans une seconde partie, est etudiee la stabilite structurale de ces materiaux apres des recuits de 300 a 450 deg. C, et de 10 a 1000 heures. Sont presentees les variations, apres ces traitements thermiques, de la grosseur du grain, et des caracteristiques mecaniques de traction a la temperature ambiante. Enfin, quelques diagrammes de vitesse de fluage et de durees de vie sont presentes sur ces materiaux pour des temperatures variant entre 300 et 450 deg. C. (auteur)

  2. Machine Casting of Ferrous Alloys (United States)


    1976 g DTIC 8 AELECTEI% UJ %AUG2 31985|| —J mjfr %M ^ B rra M B5 8 23 151 l-TT-WFtf.^ viH »<.wil»t«^lvi»wmrgT1i^^V\\’.-’\\’.^VA’ ,T...Slurry Producer . . 13 4. Laboratory Casting Machine 15 IV. STRUCTURE, SEGREGATION, HOMOGENIZATION HEAT TREATMENT , AND MECHANICAL PROPERTIES OF...RHEOCAST ALLOYS 18 1. Effect of Process Variables on Structure 18 2. Segregation, Homogenization Heat Treatment and Mechanical Properties 22 V

  3. Braze alloy spreading on steel (United States)

    Siewert, T. A.; Heine, R. W.; Lagally, M. G.


    Scanning electron microscopy (SEM) and Auger electron microscopy (AEM) were employed to observe elemental surface decomposition resulting from the brazing of a copper-treated steel. Two types of steel were used for the study, stainless steel (treated with a eutectic silver-copper alloy), and low-carbon steel (treated with pure copper). Attention is given to oxygen partial pressure during the processes; a low enough pressure (8 x 10 to the -5th torr) was found to totally inhibit the spreading of the filler material at a fixed heating cycle. With both types of steel, copper treatment enhanced even spreading at a decreased temperature.

  4. A novel method of aluminum-gadolinium master alloy production (United States)

    Maksimtsev, Konstantin; Krylosov, Andrey; Polovov, Ilya; Zhilyakov, Arkadiy; Belikov, Sergey; Volkovich, Vladimir; Rebrin, Oleg


    A new method for manufacturing aluminum-gadolinium master alloy was designed. It is based on an exchange reaction between metallic aluminum and gadolinium fluoride. The structure on the synthesized alloys with different gadolinium content was investigated. Al and Al3Gd were the main phases present in the alloys. Mechanical and thermophysical properties of the master-alloys obtained were measured.

  5. Crystallographic attributes of a shape-memory alloy


    Bhattacharya, Kaushik


    Shape-memory Alloys are attractive for many potential applications. In an attempt to provide ideas and guidelines for the development of new shape-memory alloys, this paper reports on a series of investigations that examine the reasons in the crystallography that make (i) shape-memory alloys special amongst martensites and (ii) Nickel-Titanium special among shape-memory alloys.

  6. Recent research and developments on wrought magnesium alloys

    Directory of Open Access Journals (Sweden)

    Sihang You


    Full Text Available Wrought magnesium alloys attract special interests as lightweight structural material due to their homogeneous microstructure and enhanced mechanical properties compared to as-cast alloys. In this contribution, recent research and developments on wrought magnesium alloys are reviewed from the viewpoint of the alloy design, focusing on Mg-Al, Mg-Zn and Mg-rare earth (RE systems. The effects of different alloying elements on the microstructure and mechanical properties are described considering their strengthening mechanisms, e.g. grain refinement, precipitation and texture hardening effect. Finally, the new alloy design and also the future research of wrought magnesium alloys to improve their mechanical properties are discussed.

  7. Aeronautical requirements for Inconel 718 alloy (United States)

    Elefterie, C. F.; Guragata, C.; Bran, D.; Ghiban, B.


    The project goal is to present the requirements imposed by aviation components made from super alloys based on Nickel. A significant portion of fasteners, locking lugs, blade retainers and inserts are manufactured from Alloy 718. The thesis describes environmental factors (corrosion), conditions of external aggression (salt air, intense heat, heavy industrial pollution, high condensation, high pressure), mechanical characteristics (tensile strength, yield strength and fatigue resistance) and loadings (tensions, compression loads) that must be satisfied simultaneously by Ni-based super alloy, compared to other classes of aviation alloys (as egg. Titanium alloys, Aluminum alloys). For this alloy the requirements are strength durability, damage tolerance, fail safety and so on. The corrosion can be an issue, but the fatigue under high-magnitude cyclic tensile loading it’s what limits the lifetime of the airframe. Also, the excellent malleability and weldability characteristics of the 718 system make the material physical properties tolerant of manufacturing processes. These characteristics additionally continue to provide new opportunities for advanced manufacturing methods.

  8. Vapor phase lubrication of high temperature alloys

    Energy Technology Data Exchange (ETDEWEB)

    Hanyaloglu, B.F.; Graham, E.E.; Oreskovic, T.; Hajj, C.G. [Cleveland State Univ., OH (United States)


    In a previous study, it was found that when a nickel-based superalloy IN750 was heated to high temperatures, a passive layer of aluminum oxide formed on the surface, preventing vapor phase lubrication. In this study, two nickel-chrome-iron alloys and a nickel-copper alloy were studied for high temperature lubrication to see if these alloys, which contained small amounts of aluminum, would exhibit similar behavior. It was found that under static conditions, all three alloys formed a lubricious nodular coating when exposed to a vapor of aryl phosphate. Under dynamic sliding conditions at 500{degrees}C, these alloys were successfully lubricated with a coefficient of friction of 0.1 and no detectable wear. In order to explain these results, a direct correlation between successful vapor phase lubrication and the composition of the alloys containing aluminum has been proposed. If the ratio of copper/aluminum or iron/aluminum is greater that 100 vapor phase, lubrication will be successful. If the ratio is less than 10, a passive aluminum oxide layer will prevent vapor phase lubrication. By selecting alloys with a high iron or copper content, vapor phase lubrication can provide excellent lubrication at high temperatures. 14 refs., 11 figs., 1 tab.

  9. Indium Helps Strengthen Al/Cu/Li Alloy (United States)

    Blackburn, Linda B.; Starke, Edgar A., Jr.


    Experiments on Al/Cu/Li alloys focus specifically on strengthening effects of minor additions of In and Cd. Indium-bearing alloy combines low density with ability to achieve high strength through heat treatment alone. Tensile tests on peak-aged specimens indicated that alloy achieved yield strength approximately 15 percent higher than baseline alloy. Alloy highly suitable for processing to produce parts of nearly net shape, with particular applications in aircraft and aerospace vehicles.

  10. Fatigue Characteristics of Selected Light Metal Alloys

    Directory of Open Access Journals (Sweden)

    Cieśla M.


    Full Text Available The paper addresses results of fatigue testing of light metal alloys used in the automotive as well as aerospace and aviation industries, among others. The material subject to testing comprised hot-worked rods made of the AZ31 alloy, the Ti-6Al-4V two-phase titanium alloy and the 2017A (T451 aluminium alloy. Both low- and high-cycle fatigue tests were conducted at room temperature on the cycle asymmetry ratio of R=-1. The low-cycle fatigue tests were performed using the MTS-810 machine on two levels of total strain, i.e.Δεc= 1.0% and 1.2%. The high-cycle fatigue tests, on the other hand, were performed using a machine from VEB Werkstoffprufmaschinen-Leipzig under conditions of rotary bending. Based on the results thus obtained, one could develop fatigue life characteristics of the materials examined (expressed as the number of cycles until failure of sample Nf as well as characteristics of cyclic material strain σa=f(N under the conditions of low-cycle fatigue testing. The Ti-6Al-4V titanium alloy was found to be characterised by the highest value of fatigue life Nf, both in lowand high-cycle tests. The lowest fatigue life, on the other hand, was established for the aluminium alloys examined. Under the high-cycle fatigue tests, the life of the 2017A aluminium and the AZ31 magnesium alloy studied was determined by the value of stress amplitude σa. With the stress exceeding 150 MPa, it was the aluminium alloy which displayed higher fatigue life, whereas the magnesium alloy proved better on lower stress.

  11. Grain refining technique of AM60B alloy by Al-Ti-B master alloy

    Directory of Open Access Journals (Sweden)

    Chen Tijun


    Full Text Available The effects of grain refining parameters on grain size of AM60B magnesium alloy have been investigated using an Al-5Ti-1B master alloy as refiner; and an appropriate refining technique has been developed. The results indicate that the Al-Ti-B master alloy is an effective grain refiner for AM60B alloy and the grain size can be decreased from 348 μm to 76 μm. Raising the addition temperature or the pouring temperature is beneficial for grain refinement; while for the addition amount and holding time, there is an optimal value. The appropriate grain refining technique is that 0.3% Al-Ti-B master alloy is added at 780 ℃ and then the melt is held for 30 min before pouring. The above phenomena can be explained by the refining mechanisms that have been proposed from the related studies on Al and Mg alloys and theoretical analysis.

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

    Directory of Open Access Journals (Sweden)

    Qingsheng Zhang


    Full Text Available 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.

  13. Current assisted superplastic forming of titanium alloy

    Directory of Open Access Journals (Sweden)

    Wang Guofeng


    Full Text Available Current assisted superplastic forming combines electric heating technology and superplastic forming technology, and can overcome some shortcomings of traditional superplastic forming effectively, such as slow heating rate, large energy loss, low production efficiency, etc. Since formability of titanium alloy at room temperature is poor, current assisted superplastic forming is suitable for titanium alloy. This paper mainly introduces the application of current assisted superplastic forming in the field of titanium alloy, including forming technology of double-hemisphere structure and bellows.

  14. Graded coatings for metallic implant alloys

    Energy Technology Data Exchange (ETDEWEB)

    Saiz, Eduardo; Tomsia, Antoni P.; Fujino, Shigeru; Gomez-Vega, Jose M.


    Graded glass and glass-hydroxyapatite coatings on Ti-based and Co-Cr alloys have been prepared using a simple enameling technique. The composition of the glasses has been tailored to match the thermal expansion of the alloys. By controlling the firing time, and temperature, it has been possible to control the reactivity between the glass and the alloy and to fabricate coatings (25 to 150 mu m thick) with excellent adhesion to the substrate, resistant to corrosion and able to precipitate hydroxyapatite during in vitro tests in simulated body fluid.

  15. New alloys to conserve critical elements (United States)

    Stephens, J. R.


    Based on availability of domestic reserves, chromium is one of the most critical elements within the U.S. metal industry. New alloys having reduced chromium contents which offer potential as substitutes for higher chromium containing alloys currently in use are being investigated. This paper focuses primarily on modified Type 304 stainless steels having one-third less chromium, but maintaining comparable oxidation and corrosion properties to that of type 304 stainless steel, the largest single use of chromium. Substitutes for chromium in these modified Type 304 stainless steel alloys include silicon and aluminum plus molybdenum.

  16. Stress corrosion cracking of titanium alloys (United States)

    Statler, G. R.; Spretnak, J. W.; Beck, F. H.; Fontana, M. G.


    The effect of hydrogen on the properties of metals, including titanium and its alloys, was investigated. The basic theories of stress corrosion of titanium alloys are reviewed along with the literature concerned with the effect of absorbed hydrogen on the mechanical properties of metals. Finally, the basic modes of metal fracture and their importance to this study is considered. The experimental work was designed to determine the effects of hydrogen concentration on the critical strain at which plastic instability along pure shear directions occurs. The materials used were titanium alloys Ti-8Al-lMo-lV and Ti-5Al-2.5Sn.

  17. Development of Lightweight Titanium Base Alloys (United States)


    as base alloy compositions. After the program began, the gamma-Ti-35A1 alloy was added. The principal thrust was to add significant amounts of Be to...creepresistance at high temperatures. A secondary thrust of this program was to add Li arid Mg to the base alloys in sufficient concentrations to decrease overall...selected al!oy samples were determined by using the Archimedes technique with water at 23°C; these densities are compared with densities of tne

  18. Magnetization curve modelling of soft magnetic alloys

    Energy Technology Data Exchange (ETDEWEB)

    Meszaros, I, E-mail: [Department of Materials Science and Engineering, Budapest University of Technology and Economics, Bertalan L. street 7., Budapest, H-1111 (Hungary)


    In this paper we present an application of the so called hyperbolic model of magnetization. The model was modified and it was applied for nine different soft magnetic alloys. The tested samples were electro-technical steels (FeSi alloys) and a permalloy (FeNi alloy) with strongly different magnetic properties. Among them there are top, medium and definitely poor quality soft magnetic materials as well. Their minor hysteresis loops and normal magnetization curves were measured by alternating current measurement. The hyperbolic model of magnetization was applied for the experimental normal magnetization curves. It was proved that the applied model is excellent for describing mathematically the experimental magnetization curves.

  19. Influence of the selected alloy additions on limiting the phase formation in Cu-Zn alloys

    Directory of Open Access Journals (Sweden)

    J. Kozana


    Full Text Available Influence of the selected alloy additions into copper and zinc alloys was investigated in order to find out the possibility of limiting the precipitation of unfavourable phase . The observation of microstructures and strength tests were performed. The results of metallographic and strength investigations indicate positive influence of small amounts of nickel, cobalt or tellurium. The precise determination of the influence of the selected alloy additions on limiting the gamma phase formation will be the subject of further examinations.

  20. HAYNES 244 alloy – a new 760 ∘C capable low thermal expansion alloy


    Fahrmann Michael G.; Srivastava S. Krishna; Pike Lee M.


    HAYNES® 244TM alloy is a new 760∘C capable, high strength low thermal expansion (CTE) alloy. Its nominal chemical composition in weight percent is Ni – 8 Cr – 22.5 Mo – 6 W. Recently, a first mill-scale heat of 244 alloy was melted by Haynes International, and processed to various product forms such as re-forge billet, plate, and sheet. This paper presents key attributes of this new alloy (CTE, strength, low-cycle fatigue performance, oxidation resistance, thermal stability) as they pertain t...

  1. HAYNES 244 alloy – a new 760 ∘C capable low thermal expansion alloy

    Directory of Open Access Journals (Sweden)

    Fahrmann Michael G.


    Full Text Available HAYNES® 244TM alloy is a new 760∘C capable, high strength low thermal expansion (CTE alloy. Its nominal chemical composition in weight percent is Ni – 8 Cr – 22.5 Mo – 6 W. Recently, a first mill-scale heat of 244 alloy was melted by Haynes International, and processed to various product forms such as re-forge billet, plate, and sheet. This paper presents key attributes of this new alloy (CTE, strength, low-cycle fatigue performance, oxidation resistance, thermal stability as they pertain to the intended use in rings and seals of advanced gas turbines.

  2. Wear resistance of alloy вт-22 with non-ferrous alloys at reverse

    Directory of Open Access Journals (Sweden)

    А.М. Хімко


    Full Text Available  The article presents the results of tests of non hardened titanium alloy ВТ-22 with aviation non-ferrous alloys in reverse sliding friction. The main objective of the work is the selection of the optimum combination of materials depending on changes in loading conditions. Study of alloy ВТ-22 wear resistance was carried out in pairs with БрОФ-10-1, БрБ2, БрАЖ-9-4, ВТ-22, МЛ5, Д16Т, 7Х21ГАН5Ш and 95Х18Ш. The dependencies of the materials wear at pressures 10, 20 and 30 Mpa we determined. The linear nature of titanium alloy wear curves indicates that the change in the wear mechanism occurs gradually. The histograms of non-ferrous materials wear and the total wear of the friction pair are presented. It is established that the bronze БрАЖ-9-4 is the most preferable material for contact with non hardened titanium alloy ВТ-22, the least wear among the tested materials. The established coefficients of the titanium alloy ВТ-22 friction in pair with aviation structural non-ferrous alloys are presented. The results of research will be relevant for the engineering industry, where non hardened titanium alloy ВТ-22 in pair with non-ferrous alloys is applied.

  3. Effect of the selected alloying on Ni-Mn-Ga alloys

    Energy Technology Data Exchange (ETDEWEB)

    Soederberg, O.; Koho, K.; Sammi, T.; Liu, X.W.; Sozinov, A.; Lanska, N.; Lindroos, V.K


    The aim of the present study was to investigate the possibilities of changing some characteristics of ternary Ni-Mn-Ga alloys by alloying. Therefore, five quaternary materials were prepared from the same polycrystalline Ni-Mn-Ga master ternary alloy with about 2 at.% additions of Bi, Pb, Si, Sn and Zn. The transformation temperatures and Curie points of the annealed materials were determined with DSC and magnetic susceptibility measurements. The crystal structures of the alloys were determined with the X-ray diffraction. In alloys with Si and Sn phase transformations were retarded to very low temperatures or outside the observable temperature region (below 113 K). With Si alloying a clear premartensitic softening was present. Bi, Pb and Zn doping preserved the original monoclinic crystal structure of the master alloy with slight lattice parameter changes. Bi increased slightly the phase transformation temperatures and decreased the Curie point, while in the two others phase transformations were shifted little lower and Curie temperature to higher temperatures. The intermartensitic transformation present in the ternary alloy was either totally retarded or diminished to a large extent in all of the doped alloys.

  4. Incology alloy 908 data handbook

    Energy Technology Data Exchange (ETDEWEB)

    Toma, L.S.; Steeves, M.M. [Massachusetts Institute of Technology, Cambridge, MA (United States); Reed, R.P. [Cryogenic Materials Inc., Boulder, CO (United States)


    This handbook is a compilation of all available properties of Incoloy alloy 908 as of March, 1994. Data included in this paper cover mechanical, elastic, thermal and magnetic characteristics. The mechanical properties include tensile, fracture toughness, fatigue, and stress-rupture for both the base metal and related weld filler metals. Elastic properties listed are Young`s, shear and bulk moduli and Poisson`s ratio. Thermal expansion, thermal conductivity and specific heat and magnetization are also reported. Data presented are summarized in the main body and presented in detail in the supplements. Areas of ongoing research are briefly described, and topics for future research are suggested. The data have been compiled to assist in the design of large-scale superconducting magnets for fusion reactors.

  5. Silver-hafnium braze alloy (United States)

    Stephens, Jr., John J.; Hosking, F. Michael; Yost, Frederick G.


    A binary allow braze composition has been prepared and used in a bonded article of ceramic-ceramic and ceramic-metal materials. The braze composition comprises greater than approximately 95 wt % silver, greater than approximately 2 wt % hafnium and less than approximately 4.1 wt % hafnium, and less than approximately 0.2 wt % trace elements. The binary braze alloy is used to join a ceramic material to another ceramic material or a ceramic material, such as alumina, quartz, aluminum nitride, silicon nitride, silicon carbide, and mullite, to a metal material, such as iron-based metals, cobalt-based metals, nickel-based metals, molybdenum-based metals, tungsten-based metals, niobium-based metals, and tantalum-based metals. A hermetic bonded article is obtained with a strength greater than 10,000 psi.

  6. Phase diagrams for surface alloys

    DEFF Research Database (Denmark)

    Christensen, Asbjørn; Ruban, Andrei; Stoltze, Per


    of the heat of segregation from the bulk and the sign of the excess interactions between the atoms in the surface (the surface mixing energy). We also consider the more complicated cases a with ordered surface phases, nonpseudomorphic overlayers, second layer segregation, and multilayers. The discussion......We discuss surface alloy phases and their stability based on surface phase diagrams constructed from the surface energy as a function of the surface composition. We show that in the simplest cases of pseudomorphic overlayers there are four generic classes of systems, characterized by the sign...... is based on density-functional calculations using the coherent-potential approximation and on effective-medium theory. We give self-consistent density-functional results for the segregation energy and surface mixing energy for all combinations of the transition and noble metals. Finally we discuss...

  7. Copper Alloy For High-Temperature Uses (United States)

    Dreshfield, Robert L.; Ellis, David L.; Michal, Gary


    Alloy of Cu/8Cr/4Nb (numbers indicate parts by atom percent) improved over older high-temperature copper-based alloys in that it offers enhanced high temperature strength, resistance to creep, and ductility while retaining most of thermal conductivity of pure copper; in addition, alloy does not become embrittled upon exposure to hydrogen at temperatures as high as 705 degrees C. Designed for use in presence of high heat fluxes and active cooling; for example, in heat exchangers in advanced aircraft and spacecraft engines, and other high-temperature applications in which there is need for such material. High conductivity and hardness of alloy exploited in welding electrodes and in high-voltage and high-current switches and other applications in which wear poses design problem.

  8. Theory of Rare-Earth Alloys

    DEFF Research Database (Denmark)

    Lindgård, Per-Anker


    A mean-field random alloy theory combined with a simple calculation of the exchange interaction J(c,Q) is shown to quantitatively account for the phase diagrams for alloys of rare-earth metals with Y, Lu, Sc, and other rare-earth metals. A concentration-dependent J(c,Q) explains the empirical 2...... to account for all alloys except the Sc based. The exceptional behavior of the Sc alloys is due to a low density of states for Sc. A brief discussion is given of the effect on the mean-field results of changes in volume or c/a ratio and of critical fluctuations. Since the physical mechanisms of these ideal...


    Directory of Open Access Journals (Sweden)

    V. Ju. Stetsenko


    Full Text Available It is shown that antifriction aluminium-silicon alloy is perspective material for change of the parts of heavy and expensive bronze in different frictional units of machines and mechanisms.

  10. NASA-427: A New Aluminum Alloy (United States)

    Nabors, Sammy A.


    NASA's Marshall Space Flight Center researchers have developed a new, stronger aluminum alloy, ideal for cast aluminum products that have powder or paint-baked thermal coatings. With advanced mechanical properties, the NASA-427 alloy shows greater tensile strength and increased ductility, providing substantial improvement in impact toughness. In addition, this alloy improves the thermal coating process by decreasing the time required for heat treatment. With improvements in both strength and processing time, use of the alloy provides reduced materials and production costs, lower product weight, and better product performance. The superior properties of NASA-427 can benefit many industries, including automotive, where it is particularly well-suited for use in aluminum wheels.

  11. Development of creep resistant magnesium diecasting alloys

    Energy Technology Data Exchange (ETDEWEB)

    Pekguleryuz, M.O. [Noranda Technol. Center, Que. (Canada)


    The most economic use of magnesium in the automotive industry presently is in diecast applications because of the high productivity of the diecasting process that upsets the relatively high cost of the magnesium metal. The current commercial magnesium alloys developed for diecasting applications fall into two classes. The first group is based on the Mg-Al system and the Mg-Al-Zn systems. These alloys have been developed for good room temperature strength and/or ductility but do not exhibit good creep resistance. The second group of alloys has been developed for improved elevated-temperature performance and are based on the Mg-Al-RE and Mg-Al-Si systems. These second group alloys offer either borderline improvement in creep resistance (Mg-Al-Si) or have cost or other disadvantages despite the good creep resistance (Mg- Al-RE).

  12. Solid solution lithium alloy cermet anodes (United States)

    Richardson, Thomas J.


    A metal-ceramic composite ("cermet") has been produced by a chemical reaction between a lithium compound and another metal. The cermet has advantageous physical properties, high surface area relative to lithium metal or its alloys, and is easily formed into a desired shape. An example is the formation of a lithium-magnesium nitride cermet by reaction of lithium nitride with magnesium. The reaction results in magnesium nitride grains coated with a layer of lithium. The nitride is inert when used in a battery. It supports the metal in a high surface area form, while stabilizing the electrode with respect to dendrite formation. By using an excess of magnesium metal in the reaction process, a cermet of magnesium nitride is produced, coated with a lithium-magnesium alloy of any desired composition. This alloy inhibits dendrite formation by causing lithium deposited on its surface to diffuse under a chemical potential into the bulk of the alloy.

  13. Room temperature creep in metals and alloys

    Energy Technology Data Exchange (ETDEWEB)

    Deibler, Lisa Anne [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Materials Characterization and Performance


    Time dependent deformation in the form of creep and stress relaxation is not often considered a factor when designing structural alloy parts for use at room temperature. However, creep and stress relaxation do occur at room temperature (0.09-0.21 Tm for alloys in this report) in structural alloys. This report will summarize the available literature on room temperature creep, present creep data collected on various structural alloys, and finally compare the acquired data to equations used in the literature to model creep behavior. Based on evidence from the literature and fitting of various equations, the mechanism which causes room temperature creep is found to include dislocation generation as well as exhaustion.

  14. Study of fluoride corrosion of nickel alloys (United States)

    Gunther, W. H.; Steindler, M. J.


    Report contains the results of an investigation of the corrosion resistance of nickel and nickel alloys exposed to fluorine, uranium hexafluoride, and volatile fission product fluorides at high temperatures. Survey of the unclassified literature on the subject is included.


    Directory of Open Access Journals (Sweden)

    Eva Mazancová


    Full Text Available Stacking fault energy of high manganese alloys (marked as TWIP and TRIPLEX is an important parameter determining deformation mechanism type realized in above mentioned alloys. Stacking fault energy level can be asserted with a gliding of partial and/or full dislocations, b gliding mechanism and twinning deformation process in connection with increasing of fracture deformation level (deformation elongation and with increasing of simultaneously realized work hardening proces., c gliding mechanism and deformation induced e-martensite formation. In contribution calculated stacking fault energies are presented for various chemical compositions of high manganese alloys. Stacking fault energy dependences on manganese, carbon, iron and alluminium contents are presented. Results are confronted with some accessible papers.The aim of work is to deepen knowledge of presented data. The TWIP and TRIPLEX alloys can be held for promissing new automotive materials.

  16. Shape Memory Alloy Rock Splitters (SMARS) (United States)

    Benafan, Othmane (Inventor); Noebe, Ronald D. (Inventor)


    Shape memory alloys (SMAs) may be used for static rock splitting. The SMAs may be used as high-energy multifunctional materials, which have a unique ability to recover large deformations and generate high stresses in response to thermal loads.

  17. Hydrogen treatment of titanium based alloys (United States)

    Losertová, M.; Hartmann, M.; Schindler, I.; Drápala, J.


    The positive effect of the hydrogen on hot deformation behaviour at 700 and 750 °C was investigated after thermal hydrogen treatment of Ti6Al4V and Ti26Nb alloys. Comparing the results obtained for the non-hydrogenated and hydrogenated specimens of both alloys, it was found that the hydrogen content as high as 1325 wt. ppm has an obvious benefit effect on high temperature deformation behaviour in the Ti6Al4V alloy by stabilizing beta phase and lowering thermal deformation resistance. In the case of Ti26Nb alloy the hydrogen content of 2572 wt. ppm suppressed stress instabilities during hot compression but slightly increased thermal deformation resistance. The microstructure study was performed before and after the isothermal compression tests on the specimens in hydrogenated as well as in non-hydrogenated condition. The hydrogen amounts in the specimens were measured by means of an analyser LECO RH600.

  18. Simulation and Modeling in High Entropy Alloys (United States)

    Toda-Caraballo, I.; Wróbel, J. S.; Nguyen-Manh, D.; Pérez, P.; Rivera-Díaz-del-Castillo, P. E. J.


    High entropy alloys (HEAs) is a fascinating field of research, with an increasing number of new alloys discovered. This would hardly be conceivable without the aid of materials modeling and computational alloy design to investigate the immense compositional space. The simplicity of the microstructure achieved contrasts with the enormous complexity of its composition, which, in turn, increases the variety of property behavior observed. Simulation and modeling techniques are of paramount importance in the understanding of such material performance. There are numerous examples of how different models have explained the observed experimental results; yet, there are theories and approaches developed for conventional alloys, where the presence of one element is predominant, that need to be adapted or re-developed. In this paper, we review of the current state of the art of the modeling techniques applied to explain HEAs properties, identifying the potential new areas of research to improve the predictability of these techniques.

  19. Alloy solution hardening with solute pairs (United States)

    Mitchell, John W.


    Solution hardened alloys are formed by using at least two solutes which form associated solute pairs in the solvent metal lattice. Copper containing equal atomic percentages of aluminum and palladium is an example.

  20. Stress-corrosion cracking of titanium alloys. (United States)

    Blackburn, M. J.; Feeney, J. A.; Beck, T. R.


    In the light of research material published up to May 1970, the current understanding of the experimental variables involved in the stress-corrosion cracking (SCC) behavior of titanium and its alloys is reviewed. Following a brief summary of the metallurgy and electrochemistry of titanium alloys, the mechanical, electrochemical, and metallurgical parameters influencing SCC behavior are explored with emphasis on crack growth kinetics. Macro- and microfeatures of fractures are examined, and it is shown that many transgranular SCC failures exhibit morphological and crystallographic features similar to mechanical cleavage failures. Current SCC models are reviewed with respect to their ability to explain the observed SCC behavior of titanium and its alloys. Possible methods for eliminating or minimizing stress corrosion hazards in titanium or titanium alloy components are described.

  1. Surface Phases in Binary Liquid Metal Alloys


    Tostmann, Holger; DiMasi, Elaine; Shpyrko, Oleg G.; Ocko, Ben M.; Pershan, Peter S.; Deutsch, Moshe


    Surface sensitive x-ray scattering techniques with atomic scale resolution are employed to investigate the microscopic structure of the surface of three classes of liquid binary alloys: (i) Surface segregation in partly miscible binary alloys as predicted by the Gibbs adsorption rule is investigated for Ga-In. The first layer consists of a supercooled In monolayer and the bulk composition is reached after about two atomic diameters. (ii) The Ga-Bi system displays a wetting transition at a cha...

  2. Internal gettering by metal alloy clusters (United States)

    Buonassisi, Anthony; Heuer, Matthias; Istratov, Andrei A.; Pickett, Matthew D.; Marcus, Mathew A.; Weber, Eicke R.


    The present invention relates to the internal gettering of impurities in semiconductors by metal alloy clusters. In particular, intermetallic clusters are formed within silicon, such clusters containing two or more transition metal species. Such clusters have melting temperatures below that of the host material and are shown to be particularly effective in gettering impurities within the silicon and collecting them into isolated, less harmful locations. Novel compositions for some of the metal alloy clusters are also described.

  3. Degassing of Aluminum Alloys Using Ultrasonic Vibration

    Energy Technology Data Exchange (ETDEWEB)

    Meek, T. T.; Han, Q.; Xu, H.


    The research was intended to lead to a better fundamental understanding of the effect of ultrasonic energy on the degassing of liquid metals and to develop practical approaches for the ultrasonic degassing of alloys. The goals of the project described here were to evaluate core principles, establish a quantitative basis for the ultrasonic degassing of aluminum alloy melts, and demonstrate the application of ultrsaonic processing during ingot casting and foundry shape casting.

  4. Reduction Expansion Synthesis for Magnetic Alloy Powders (United States)


    12 Figure 6. RES Particle Size Distribution Iron-Nickel alloy. .....................................14 Figure 7. Copper Particles a...diameter was less than 150 nm. Finally, it was suggested that the RES technique can be adapted for additional alloys, as well as graphene ...expand RES to wider applications. In [18], RES was used to reduce graphite oxide in order to produce graphene sheets. This study demonstrates the

  5. Titanium and titanium alloys fundamentals and applications

    CERN Document Server

    Peters, Manfred


    This handbook is an excellent reference for materials scientists and engineers needing to gain more knowledge about these engineering materials. Following introductory chapters on the fundamental materials properties of titanium, readers will find comprehensive descriptions of the development, processing and properties of modern titanium alloys. There then follows detailed discussion of the applications of titanium and its alloys in aerospace, medicine, energy and automotive technology.

  6. Phonon broadening in high entropy alloys (United States)

    Körmann, Fritz; Ikeda, Yuji; Grabowski, Blazej; Sluiter, Marcel H. F.


    Refractory high entropy alloys feature outstanding properties making them a promising materials class for next-generation high-temperature applications. At high temperatures, materials properties are strongly affected by lattice vibrations (phonons). Phonons critically influence thermal stability, thermodynamic and elastic properties, as well as thermal conductivity. In contrast to perfect crystals and ordered alloys, the inherently present mass and force constant fluctuations in multi-component random alloys (high entropy alloys) can induce significant phonon scattering and broadening. Despite their importance, phonon scattering and broadening have so far only scarcely been investigated for high entropy alloys. We tackle this challenge from a theoretical perspective and employ ab initio calculations to systematically study the impact of force constant and mass fluctuations on the phonon spectral functions of 12 body-centered cubic random alloys, from binaries up to 5-component high entropy alloys, addressing the key question of how chemical complexity impacts phonons. We find that it is crucial to include both mass and force constant fluctuations. If one or the other is neglected, qualitatively wrong results can be obtained such as artificial phonon band gaps. We analyze how the results obtained for the phonons translate into thermodynamically integrated quantities, specifically the vibrational entropy. Changes in the vibrational entropy with increasing the number of elements can be as large as changes in the configurational entropy and are thus important for phase stability considerations. The set of studied alloys includes MoTa, MoTaNb, MoTaNbW, MoTaNbWV, VW, VWNb, VWTa, VWNbTa, VTaNbTi, VWNbTaTi, HfZrNb, HfMoTaTiZr.

  7. Oxidation of alloys for advanced steam turbines

    Energy Technology Data Exchange (ETDEWEB)

    Holcomb, Gordon R.; Covino, Bernard S., Jr.; Bullard, Sophie J.; Ziomek-Moroz, M.; Alman, David E.


    Ultra supercritical (USC) power plants offer the promise of higher efficiencies and lower emissions. Current goals of the U.S. Department of Energy’s Advanced Power Systems Initiatives include coal generation at 60% efficiency, which would require steam temperatures of up to 760°C. This research examines the steamside oxidation of advanced alloys for use in USC systems, with emphasis placed on alloys for high- and intermediate-pressure turbine sections.

  8. Research and Development on Titanium Alloys (United States)


    are being prepared by the Norton Company for evaluation. Titanium boride , tantalum boride , zirconium boride , tungsten boride , and molybdenum boride ...alloying additionO will be ex- tended. 9 Ternary alloys of manganese and carbon, manganese and vanadium, and molybdenum and tungsten, prepared by...graphite crucibles lined with tantalum carbide and turgsten boride as refractories for molten titanium,. Melts were prepared In crucibles made of zirconium

  9. Ternary alloy nanocatalysts for hydrogen evolution reaction

    Indian Academy of Sciences (India)

    Cu–Fe–Ni ternary alloys (size ∼55–80 nm) with varying compositions viz. CuFeNi (A1), CuFe2Ni (A2) and CuFeNi2 (A3) were successfully synthesized using microemulsion. It is to be noted that synthesis of nanocrystallineternary alloys with precise composition is a big challenge which can be overcome by choosing an ...

  10. Fracture & Fatigue Characteristics in Titanium Alloys. (United States)


    Part III is directed at characterizing internal fatigue crack initiation sites in an a/s alloy. Part I includes a systematic study of the effect of sub...electrochemically polished or shot peened. Prior to fatigue testing, the surface residual stresses were measured in the longitudinal direction using x-ray...alloy) attests to the validity of the phase boundary positions. 7 C/3871A/cb 1 Rockwell International Scince Center SC5227.1FR The compositions of the

  11. Progress in Preparation and Research of High Entropy Alloys

    Directory of Open Access Journals (Sweden)

    CHEN Yong-xing


    Full Text Available The current high entropy alloys' studies are most in block, powder, coating, film and other areas. There are few studies of high entropy alloys in other areas and they are lack of unified classification. According to the current high entropy alloys' research situation, The paper has focused on the classification on all kinds of high entropy alloys having been researched, introduced the selecting principle of elements, summarized the preparation methods, reviewed the research institutions, research methods and research contents of high entropy alloys, prospected the application prospect of high entropy alloys, put forward a series of scientific problems of high entropy alloys, including less research on mechanism, incomplete performance research, unsystematic thermal stability study, preparation process parameters to be optimized, lightweight high entropy alloys' design, the expansion on the research field, etc, and the solutions have been given. Those have certain guiding significance for the expansion of the application of high entropy alloys subjects in the future research direction.

  12. Die casting for high performance - focus on alloy development

    Energy Technology Data Exchange (ETDEWEB)

    Bakke, P.; Westengen, H. [Hydro Aluminium a.s., Magnesium Competence Centre, PO Box 2560, N-Porsgrunn (Norway)


    Development of magnesium die casting alloys is the art of combining a thorough understanding of thermodynamic aspects of alloy composition and phase formation with the solidification kinetics as experienced in the die casting process. The microstructures obtained will determine The Alloy Property profile, which must be in line with the targeted application requirements. Successful development of an industrial alloy means that also The Diecasting Performance profile as well as the Alloy Production and Recycling profile must be fulfilled. In the present paper, a summary of current alloy development efforts will be given. Results from alloy development work by Hydro Magnesium will be presented, focusing mainly on creep resistant alloys. Specifically, alloys within the Mg-Al-RE system are highlighted. (Abstract Copyright [2003], Wiley Periodicals, Inc.)

  13. Development of Advanced Alloys using Fullerenes (United States)

    Sims, J.; Wasz, M.; O'Brien, J.; Callahan, D. L.; Barrera, E. V.


    Development of advanced alloys using fullerenes is currently underway to produce materials for use in the extravehicular mobility unit (EMU). These materials will be directed toward commercial usages as they are continually developed. Fullerenes (of which the most common is C(sub 60)) are lightweight, nanometer size, hollow molecules of carbon which can be dispersed in conventional alloy systems to enhance strength and reduce weight. In this research, fullerene interaction with aluminum is investigated and a fullerene-reinforced aluminum alloy is being developed for possible use on the EMU. The samples were manufactured using standard commercial approaches including powder metallurgy and casting. Alloys have been processed having 1.3, 4.0 and 8.0 volume fractions of fullerenes. It has been observed that fullerene dispersion is related to the processing approach and that they are stable for the processing conditions used in this research. Emphasis will be given to differential thermal analysis and wavelength dispersive analysis of the processed alloys. These two techniques are particularly useful in determining the condition of the fullerenes during and after processing. Some discussion will be given as to electrical properties of fullerene-reinforced materials. Although the aluminum and other advanced alloys with fullerenes are being developed for NASA and the EMU, the properties of these materials will be of interest for commercial applications where specific Dual-Use will be given.

  14. Capacity retention in hydrogen storage alloys (United States)

    Anani, A.; Visintin, A.; Srinivasan, S.; Appleby, A. J.; Reilly, J. J.; Johnson, J. R.


    Results of our examination of the properties of several candidate materials for hydrogen storage electrodes and their relation to the decrease in H-storage capacity upon open-circuit storage over time are reported. In some of the alloy samples examined to date, only about 10 percent of the hydrogen capacity was lost upon storage for 20 days, while in others, this number was as high as 30 percent for the same period of time. This loss in capacity is attributed to two separate mechanisms: (1) hydrogen desorbed from the electrode due to pressure differences between the cell and the electrode sample; and (2) chemical and/or electrochemical degradation of the alloy electrode upon exposure to the cell environment. The former process is a direct consequence of the equilibrium dissociation pressure of the hydride alloy phase and the partial pressure of hydrogen in the hydride phase in equilibrium with that in the electrolyte environment, while the latter is related to the stability of the alloy phase in the cell environment. Comparison of the equilibrium gas-phase dissociation pressures of these alloys indicate that reversible loss of hydrogen capacity is higher in alloys with P(eqm) greater than 1 atm than in those with P(eqm) less than 1 atm.

  15. Nickel-base alloys for severe environments

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, R.K.; Flower, H.L. [Inco Alloys International Inc., Huntington, WV (United States); Hack, G.A.J. [Inco Alloys Ltd., Hereford (United Kingdom); Isobe, S. [Daido Steel Co. Ltd., Nagoya (Japan)


    Inconel alloys MA754 and MA758 are nickel-base, oxide dispersion-strengthened superalloys made by mechanical alloying. The simple nickel-chromium matrix, when combined with the strengthening effect of the yttrium oxide dispersoid during mechanical alloys, provides excellent creep properties, resistance to thermal fatigue, and surface stability suitable for operation without protective coatings. Gas turbine engine components are primary applications for alloy MA754, but this aerospace alloy has been applied in many other products that operate in severe conditions, and alloy MA758 was developed specifically for aggressive, elevated temperature industrial environments. Billets for large bar and plate are typically consolidated by hot isostatic pressing (HIP), because this technology allows production of forms suitable for a variety of industrial components. Material consolidated by HIP and conventionally worked by extrusion and hot rolling generally exhibits properties that are more isotropic than those of material consolidated by extrusion. However, the degree of anisotropy depends strongly on the specific processing of the consolidated billet. This article describes production of new mill shapes from HIP billets, and reviews current and potential applications such as skid rails for high-temperature walking-beam furnaces, heat treating furnace parts, equipment for handling molten glass, and furnace tubes.

  16. New Stainless Steel Alloys for Low Temperature Surface Hardening?

    DEFF Research Database (Denmark)

    Christiansen, Thomas Lundin; Dahl, Kristian Vinter; Somers, Marcel A. J.


    The present contribution showcases the possibility for developing new surface hardenable stainless steels containing strong nitride/carbide forming elements (SNCFE). Nitriding of the commercial alloys, austenitic A286, and ferritic AISI 409 illustrates the beneficial effect of having SNCFE present...... in the stainless steel alloys. The presented computational approach for alloy design enables “screening” of hundreds of thousands hypothetical alloy systems by use of Thermo-Calc. Promising compositions for new stainless steel alloys can be selected based on imposed criteria, i.e. facilitating easy selection...... of candidate alloys designed for low temperature surface hardening....

  17. Comparison of the Oxidation Rates of Some New Copper Alloys (United States)

    Ogbuji, Linus U. J. Thomas; Humphrey, Donald L.


    Copper alloys were studied for oxidation resistance and mechanisms between 550 and 700 C, in reduced-oxygen environments expected in rocket engines, and their oxidation behaviors compared to that of pure copper. They included two dispersion-strengthened alloys (precipitation-strengthened and oxide-dispersion strengthened, respectively) and one solution-strengthened alloy. In all cases the main reaction was oxidation of Cu into Cu2O and CuO. The dispersion-strengthened alloys were superior to both Cu and the solution-strengthened alloy in oxidation resistance. However, factors retarding oxidation rates seemed to be different for the two dispersion-strengthened alloys.

  18. First principles analysis of hydrogen chemisorption on Pd-Re alloyed overlayers and alloyed surfaces

    DEFF Research Database (Denmark)

    Pallassana, Venkataraman; Neurock, Matthew; Hansen, Lars Bruno


    Gradient corrected periodic density functional theory (DFT-GGA) slab calculations were used to examine the chemisorption of atomic hydrogen on various Pd-Re alloyed overlayers and uniformly alloyed surfaces. Adsorption was examined at 33% surface coverage, where atomic hydrogen preferred the thre...

  19. Microstructure and magnetic properties of mechanically alloyed FeSiBAlNi (Nb) high entropy alloys (United States)

    Wang, Jian; Zheng, Zhou; Xu, Jing; Wang, Yan


    In this paper, the effects of milling duration and composition on the microstructure and magnetic properties of equi-atomic FeSiBAlNi and FeSiBAlNiNb high entropy alloys during mechanical alloying have been investigated using X-ray diffraction, differential scanning calorimetry, scanning electron microscopy, transmission electron microscopy and alternating gradient magnetometry. The amorphous high entropy alloys have been successfully fabricated using the mechanical alloying method. The results show that the Nb addition prolongs the milling time for the formation of the fully FeSiBAlNi amorphous phase and decreases the glass forming ability. However, FeSiBAlNiNb amorphous high entropy alloy has the higher thermal stability and heat resisting properties. Moreover, the as-milled FeSiBAlNi(Nb) powders are soft-magnetic materials indicated by their low coercivity. The saturation magnetization of the as-milled FeSiBAlNi(Nb) powders decreases with prolonging of the milling time and shows the lowest value when the amorphous high entropy alloys are formed. It suggests that the as-milled products with solid solution phases show the better soft-magnetic properties than those with fully amorphous phases. The Nb addition does not improve the soft-magnetic properties of the FeSiBAlNi high entropy alloys. Rather, both amorphous high entropy alloys have similar soft-magnetic properties after a long milling time.


    DEFF Research Database (Denmark)


    An electroplating method of forming platings of nickel, cobalt, nickel alloys or cobalt alloys with reduced stresses in an electrodepositing bath of the type: Watt's bath, chloride bath or a combination thereof, by employing pulse plating with periodic reverse pulse and a sulfonated naphthalene...... additive. This method makes it possible to deposit nickel, cobalt, nickel or cobalt platings without internal stresses....

  1. Effect of alloy elements on the anti-corrosion properties of low alloy ...

    Indian Academy of Sciences (India)


    Abstract. Effect of alloy elements on corrosion of low alloy steel was studied under simulated offshore condi- tions. The results showed that the elements Cu, P, Mo, W, V had evident effect on corrosion resistance in the atmosphere zone; Cu, P, V, Mo in the splash zone and Cr, Al, Mo in the submerged zone. Keywords.

  2. Nano-sized Superlattice Clusters Created by Oxygen Ordering in Mechanically Alloyed Fe Alloys (United States)

    Hu, Yong-Jie; Li, Jing; Darling, Kristopher A.; Wang, William Y.; VanLeeuwen, Brian K.; Liu, Xuan L.; Kecskes, Laszlo J.; Dickey, Elizabeth C.; Liu, Zi-Kui


    Creating and maintaining precipitates coherent with the host matrix, under service conditions is one of the most effective approaches for successful development of alloys for high temperature applications; prominent examples include Ni- and Co-based superalloys and Al alloys. While ferritic alloys are among the most important structural engineering alloys in our society, no reliable coherent precipitates stable at high temperatures have been found for these alloys. Here we report discovery of a new, nano-sized superlattice (NSS) phase in ball-milled Fe alloys, which maintains coherency with the BCC matrix up to at least 913 °C. Different from other precipitates in ferritic alloys, this NSS phase is created by oxygen-ordering in the BCC Fe matrix. It is proposed that this phase has a chemistry of Fe3O and a D03 crystal structure and becomes more stable with the addition of Zr. These nano-sized coherent precipitates effectively double the strength of the BCC matrix above that provided by grain size reduction alone. This discovery provides a new opportunity for developing high-strength ferritic alloys for high temperature applications. PMID:26134420

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

    Directory of Open Access Journals (Sweden)

    Chen Dongfeng


    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.

  4. Corrosion and wear protective composition modulated alloy coatings based on ternary Ni-P-X alloys

    DEFF Research Database (Denmark)

    Leisner, P.; Benzon, M. E.; Christoffersen, Lasse


    Scattered reporting in the litterature describes a number of ternary Ni-P-X alloyes (where X can be Co, Cr, Cu, Mo, Pd, Re or W) with promising corrosin and wear protective performance. Based on a systematic study of Ni-P-X alloys it is the intention to produce coatings with improved corrosion...

  5. Hot workability of magnesium alloys (United States)

    Mwembela, Aaron Absalom

    For the alloy AZ91 (Mg-9.OAl-0.7Zn-0.13Mn) die cast specimens were subjected to torsion testing at 150, 180, 240, 300, 420 and 450°C at 0.05 0.5 and 5.0 s--1 The as-cast specimens exhibited hot shortness at 360°C and above; however in that domain, after prior thermomechanical processing (TMP) at 300°C, they showed much improved properties (which were reported along with as-cast properties at 300°C and below). For AZ31-Mn (Mg-3.2Al-1-1Zn-0.34Mn), AZ31 (Mg-2-8Al-0-88Zn-0.01Mn), AZ63 (Mg-5-5Al-2.7Zn-0.34Mn) and ZK60 (Mg-5.7Zn-0.65Zr-O-O1A]), the specimens were subjected to hot torsion testing in the range 180 to 450°C and 0.01, 0.1, and 1.0 s--1. In the temperature range below 300°C flow curves rise to a peak with failure occurring immediately thereafter. Above 300°C the flow curves exhibited a peak and a gradual decline towards steady state. The temperature and strain rate dependence of the strength is described by a sinh-Arrhenius equation with QHW between 125 and 144 kJ/mol; this indicates control by climb in comparison with creep in the range 200--400°C. The alloy strength and activation energy declined in the order AZ63, AZ31-Mn AZ91, AZ31 and ZK60, while ductility increased with decreasing strength. In working of Mg alloys from 150 to 450°C, the flow curves harden to a peak and work soften to a steady state regime above 300°C. At temperatures below 300°C, twinning is observed initially to bring grains into more suitable slip orientations. At high T a substructure develops due to basal and prismatic slip, Forming cells of augmented misorientation first near the grain boundaries and later towards the grain cores. Near the peak, new grains appear along the old boundaries (mantle) as a result of dynamic recrystallization DRX but not in the core of the initial grains. As T rises, the new grains are larger and the mantle broader, enhanced DRX results in higher ductility. At intermediate T, shear bands form through alignment of mantle zones resulting in

  6. Catalytic properties of Ni-Zn alloy prepared by mechanical alloying for steam reforming from methanol (United States)

    Park, Jeshin; Kim, Wonbaek; Suh, Changyoul; Kim, Sangbae


    Amorphous Zn65Ni35 alloy, the composition of which lies between β1-NiZn and γ-NiZn phases, was prepared by mechanical alloying for 200 hours. The alloy was heat treated at various temperatures and leached in NaOH solution in an effort to enhance the catalytic properties for hydrogen production from methanol. X-ray diffraction study revealed that the amorphous phase crystallized during the heat treatment to the equilibrium β1-NiZn and γ-NiZn phases. It was found that Zn65Ni35 alloy leached after heat treatment at 928 K showed the highest catalytic activity for steam reforming of methanol. It is believed that the enhanced catalytic activity of the Zn65Ni35 alloy heat treated at 928 K is due to the dispersed Ni particles on β1-ZnNi matrix which was formed during leaching of the γ-Zn21Ni5 phase.

  7. Method for producing La/Ce/MM/Y base alloys, resulting alloys and battery electrodes (United States)

    Gschneidner, Jr., Karl A.; Schmidt, Frederick A.


    A carbothermic reduction method is provided for reducing a La-, Ce-, MM-, and/or Y-containing oxide in the presence of carbon and a source of a reactant element comprising Si, Ge, Sn, Pb, As, Sb, Bi, and/or P to form an intermediate alloy material including a majority of La, Ce, MM, and/or Y and a minor amount of the reactant element. The intermediate material is useful as a master alloy for in making negative electrode materials for a metal hydride battery, as hydrogen storage alloys, as master alloy additive for addition to a melt of commercial Mg and Al alloys, steels, cast irons, and superalloys; or in reducing Sm.sub.2O.sub.3 to Sm metal for use in Sm--Co permanent magnets.

  8. Development of Creep Resistant Mg-Al-Sr Alloys (United States)

    Pekguleryuz, Mihriban O.; Baril, Eric

    There have been attempts since in the 70's to develop creep resistant magnesium diecasting alloys for automotive applications such as automatic-transmission case and engine components. The earliest die casting alloys developed as a result of these activities were the Mg-Al- RE and Mg-Al-Si systems (AE and AS alloys). The shortcomings of these two alloy systems related to high cost or borderline properties have led to renewed activity in the 90's in the development of magnesium alloys with improved elevaied-temperature properties. This paper presents the development of a new family of creep-resistant Mg alloys based on the Mg-Al-Sr system. Creep resistance, the tensile yield strength and the bolt-load-retention of these alloys at 150°C and 175°C show improvement over Mg-Al-RE and Mg-Al-Si system. The microstructure of the alloys is characterized by Al-Sr-(Mg) containing intermetallic second phases. The absence of the Mg17Al12 phase in the microstructure, either creep-induced or as-cast, is one of the factors that contribute to improved creep-resistance of these alloys over the Mg-Al based diecasting alloys. Furthermore, the alloys exhibit better salt-spray corrosion resistance (0.09-0.15mg/cm2/day) than other commercial magnesium diecasting alloys such as AM60B, AS41, AE42 and the aluminum diecasting alloy A380.

  9. Experimental titanium alloys for dental applications. (United States)

    Faria, Adriana C L; Rodrigues, Renata C S; Rosa, Adalberto L; Ribeiro, Ricardo F


    Although the use of titanium has increased, casting difficulties limit routine use. The purpose of the present study was to compare the mechanical properties and biocompatibility of the experimental titanium alloys titanium-5-zirconium, titanium-5-tantalum, and titanium-5-tantalum-5-zirconium (in wt%) with those of commercially pure titanium. Specimens of titanium alloys and commercially pure titanium were cast by using plasma. Their modulus of elasticity and ultimate tensile strength were determined in a universal testing machine. Biocompatibility was evaluated with SCC9 cells. In periods of 1, 4, 7, 10, and 14 days, cell proliferation was evaluated by the (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) tetrazolium reduction assay, and cell viability was evaluated in the 7-day period. Cell morphology was evaluated at 2, 12, and 24 hours. Modulus of elasticity, ultimate tensile strength, and cell viability were analyzed by 1-way ANOVA and the Bonferroni test; cell proliferation data were compared by 2-way ANOVA (alloy versus time) and by the Bonferroni test; and the cell morphology data were analyzed by split-plot design. All statistical tests were performed at the 95% confidence level (Ptantalum presented the lowest modulus of elasticity and ultimate tensile strength, whereas titanium-5-zirconium and titanium-5-tantalum-5-zirconium were statistically similar to commercially pure titanium. Cell proliferation and viability were not affected by any alloy being similar to those observed for commercially pure titanium. No noticeably differences were found in the morphology of cells cultured on any alloy and commercially pure titanium. Experimental alloys, especially titanium-5-zirconium and titanium-5-tantalum-5-zirconium, presented promising mechanical results for future studies and clinical applications. In addition, these alloys, evaluated by cell proliferation, viability, and morphology, were found to be biocompatible in vitro. Copyright © 2014

  10. Surface Features of Nanocrystalline Alloys

    Directory of Open Access Journals (Sweden)

    Marcel Miglierini


    Full Text Available Nanocrystalline alloys are prepared by controlled annealing of metallic glass precursors. The latter are obtained by rapid quenching of a melt on a rotating wheel. This process leads to structural deviation of the produced ribbons’ surfaces. Structural features of as-quenched and thermally annealed 57Fe81Mo8Cu1B10 ribbons were studied employing Conversion Electron Mössbauer Spectrometry (CEMS and Conversion X-ray Mössbauer Spectrometry (CXMS. Enrichment of the alloy’s composition in 57Fe helped in identification of surface crystallites that were formed even during the production process. Magnetite and bcc-Fe were found at the wheel side of the as-quenched ribbons whereas only bcc-Fe nanocrystals were uncovered at the opposite air side. Accelerated formation of bcc-Fe was observed in this side of the ribbons after annealing. The relative content of magnetite at the wheel side was almost stable in near surface areas (CEMS and in more deep subsurface regions (CXMS. It vanished completely after annealing at 550 °C. No magnetite was observed at the air side of the ribbons regardless the annealing temperature and/or depth of the scanned regions.

  11. Bismuth alloy potting seals aluminum connector in cryogenic application (United States)

    Flower, J. F.; Stafford, R. L.


    Bismuth alloy potting seals feedthrough electrical connector for instrumentation within a pressurized vessel filled with cryogenic liquids. The seal combines the transformation of high-bismuth content alloys with the thermal contraction of an external aluminum tube.

  12. Assessment of Al-Li Alloys for Cryotanks (United States)

    Babel, Henry W.; Bozich, William; Farahmand, Bob; DeJesus, Ron; Sankaran, K. K.; Schwab, Dave; Tarkanian, Mike; Funk, Joan G. (Technical Monitor)


    This viewgraph presentation provides information on steps undertaken to determine the suitability of Aluminum and Lithium alloys in cryogenic tank construction. Major characteristics are offered for several different candidate alloys including reliability, weldability, flammability, and required thicknesses.

  13. The Origin of the Name "Onion's Fusible Alloy" (United States)

    Jensen, William B.


    In response to a reader query, this article traces the history of fusible alloys, including Newton's metal, D'Arcet's metal, Rose's metal, Onion's fusible alloy, and Wood's metal. (Contains 1 table and 1 figure.)

  14. Impact and modal analysis for different alloy wheel compositions (United States)

    Suman, Shwetabh; Abhimanyu Abrol, J.; Ravi, K.


    Wheels are an important component in the vehicle. The strength of the Alloy wheel rim is an important property of the Alloy wheel, which plays an important part in determining the overall performance of the vehicle, the structural integrity of the rim and the life of the Alloy wheel rim. With the advent of new Alloy wheel materials, new options are available to replace the conventional Aluminium Alloy wheels with new ones. The new Alloy wheel rim material and design need to be tested virtually for optimizing the appropriate design and material and the optimised wheel in virtual mode can be tested experimentally for the performance in real-time conditions before they can be used in the vehicles. The work in this project includes doing the impact and modal analysis for different alloy wheel compositions. From the results obtained, the optimum alloy wheel is suggested, which can be considered with further experimental validation.


    Directory of Open Access Journals (Sweden)

    О. V. Diachenko


    Full Text Available The paper is devoted to investigations on influence of laser treatment regimes of gas-thermal and adhesive coatings from self-fluxing powders on iron basis and after melting with modifying plaster on their roughness and phase composition. One of mathematical planning methods that is a complete factor experiment method has been used for investigation of parameters’ influence on micro-geometry of coatings. The executed investigations have made it possible to observe a general regularity which does not depend on a type of alloying plaster: while increasing speed of laser beam relatively to treated part, beam diameter value of Ra parameter is becoming less. Decrease in height of surface irregularities in case of increasing laser beam speed is related with intensification of evaporation processes. An increase in beam diameter diminishes Ra parameter of the surface. This is due to the fact that decrease in power density occurs at high rate of beam defocusing. Overlapping coefficient does not exert a pronounced effect on Ra parameter of fused coatings. While increasing the speed of laser beam relatively to the part structure is transferred from dendrite into supersaturated one with carbide and boride precipitations. It has been established that technological parameters of laser treatment and particularly speed of laser beam influence on coating composition. While increasing the speed up to v5 = 5 × 10–3 m/s amount of chromium has become larger by 1.5-fold that resulted in increase of micro-hardness of the coating from 9.5–10.1 GPa up to 11.04–15.50 GPa.

  16. Electromigration testing of Al alloy films (United States)

    Ghate, P. B.


    A search for reliability improvement of Al film interconnections has led to the introduction of Al-Alloy films such as Al-Cu, Al-Cu-Si and so on. This report describes the results of an in-depth study of Al, Al-Cu (2 wt % Cu) and Al-Cu-Si (2 wt % Cu - 1% Si) film interconnections and Silicon/Al-Alloy film contacts as they impact reliability of integrated circuits. Resistivity, microstructure and composition of Al-Alloy films vacuum deposited from an induction heated source (IN-Source) and dc magnetron sputter deposition techniques have been investigated and it is concluded that IN-Source and dc magnetron sputter deposition techniques are equally capable of producing Al, Al-Cu (2 wt %) and Al-Cu-Si (2 wt % Cu - 1% Si) films of comparable compositions, resistivity and microstructure. Chemical analysis X-ray fluorescence electron microprobe, scanning and transmission electron microscopy and ion microprobe have been employed for Al-Alloy film characterization. Availability of automated dc magnetron sputter (M-S) deposition equipment was a primary factor in the selection of magnetron sputter deposited Al-Alloy films for electromigration testing.

  17. Precision forging technology for aluminum alloy (United States)

    Deng, Lei; Wang, Xinyun; Jin, Junsong; Xia, Juchen


    Aluminum alloy is a preferred metal material for lightweight part manufacturing in aerospace, automobile, and weapon industries due to its good physical properties, such as low density, high specific strength, and good corrosion resistance. However, during forging processes, underfilling, folding, broken streamline, crack, coarse grain, and other macro- or microdefects are easily generated because of the deformation characteristics of aluminum alloys, including narrow forgeable temperature region, fast heat dissipation to dies, strong adhesion, high strain rate sensitivity, and large flow resistance. Thus, it is seriously restricted for the forged part to obtain precision shape and enhanced property. In this paper, progresses in precision forging technologies of aluminum alloy parts were reviewed. Several advanced precision forging technologies have been developed, including closed die forging, isothermal die forging, local loading forging, metal flow forging with relief cavity, auxiliary force or vibration loading, casting-forging hybrid forming, and stamping-forging hybrid forming. High-precision aluminum alloy parts can be realized by controlling the forging processes and parameters or combining precision forging technologies with other forming technologies. The development of these technologies is beneficial to promote the application of aluminum alloys in manufacturing of lightweight parts.

  18. Amorphous Alloy Surpasses Steel and Titanium (United States)


    In the same way that the inventions of steel in the 1800s and plastic in the 1900s sparked revolutions for industry, a new class of amorphous alloys is poised to redefine materials science as we know it in the 21st century. Welcome to the 3rd Revolution, otherwise known as the era of Liquidmetal(R) alloys, where metals behave similar to plastics but possess more than twice the strength of high performance titanium. Liquidmetal alloys were conceived in 1992, as a result of a project funded by the California Institute of Technology (CalTech), NASA, and the U.S. Department of Energy, to study the fundamentals of metallic alloys in an undercooled liquid state, for the development of new aerospace materials. Furthermore, NASA's Marshall Space Flight Center contributed to the development of the alloys by subjecting the materials to testing in its Electrostatic Levitator, a special instrument that is capable of suspending an object in midair so that researchers can heat and cool it in a containerless environment free from contaminants that could otherwise spoil the experiment.

  19. [Superplastic forming of titanium alloy denture base]. (United States)

    Okuno, O; Nakano, T; Hamanaka, H; Miura, I; Ito, M; Ai, M; Okada, M


    Ti-6Al-4V alloy has both excellent biocompatibility and superior mechanical properties. This Ti-6Al-4V can be deformed greatly and easily at the superplastic temperature of 800 degrees C to 900 degrees C. The superplastic forming of Ti-6Al-4V was made to apply to fabrication of denture base. Almost the same procedure as for dental casting mold was employed in producing the superplastic forming die by the improved phosphate bonded investment. In the pressure vessel of heat resistant alloy, Ti-6Al-4V plate was formed superplastically on the die by argon gas pressure at 850 degrees C. The fit of superplactic forming Ti-6Al-4V denture base was better than that of casting Co-Cr alloy denture bases. The Ti-6Al-4V alloy might react a little with the die. Because micro Vikers hardness of the cross-section did not go up too much near the surfaces. Even just after being formed, the surfaces were much smoother than that of Co-Cr alloy casting. The tensile strength and yield strength of superplastic forming Ti-6Al-4V were higher than those of Co-Cr castings. The elongation was about 10%. These results show that superplastic forming of Ti-6Al-4V would be suitable for a denture base.

  20. The effect of remelting various combinations of new and used cobalt-chromium alloy on the mechanical properties and microstructure of the alloy

    Directory of Open Access Journals (Sweden)

    Sharad Gupta


    Conclusion: Repeated remelting of base metal alloy for dental casting without addition of new alloy can affect the mechanical properties of the alloy. Microstructure analysis shows deterioration upon remelting. However, the addition of 25% and 50% (by weight of new alloy to the remelted alloy can bring about improvement both in mechanical properties and in microstructure.

  1. Microstructure and Aging of Powder-Metallurgy Al Alloys (United States)

    Blackburn, L. B.


    Report describes experimental study of thermal responses and aging behaviors of three new aluminum alloys. Alloys produced from rapidly solidified powders and contain 3.20 to 5.15 percent copper, 0.24 to 1.73 percent magnesium, 0.08 to 0.92 percent iron, and smaller amounts of manganese, nickel, titanium, silicon, and zinc. Peak hardness achieved at lower aging temperatures than with standard ingot-metallurgy alloys. Alloys of interest for automobile, aircraft, and aerospace applications.

  2. Effective and Environmentally Friendly Nickel Coating on the Magnesium Alloy


    Ivana Škugor Rončević; Mirjana Metikoš-Huković; Marijo Buzuk; Nives Vladislavić


    The low density and good mechanical properties make magnesium and its alloys attractive construction materials in the electronics, automotive, and aerospace industry, together with application in medicine due to their biocompatibility. Magnesium AZ91D alloy is an alloy with a high content of aluminum, whose mechanical properties overshadow the low corrosion resistance caused by the composition of the alloy and the existence of two phases: α magnesium matrix and β magnesium aluminum intermetal...

  3. [Metallurgical differentiation of cobalt-chromium alloys for implants]. (United States)

    Holzwarth, U; Thomas, P; Kachler, W; Göske, J; Schuh, A


    Cobalt Chromium alloys are used in cemented total hip or knee arthroplasty as well as in metal-on-metal bearings in total hip arthroplasty. An increasing number of publications report about (allergic) reactions to wear particles of Cobalt Chromium alloys. Reactions to nickel are more frequent in comparison to Cobalt or Chromium particles. It is well known that different kinds of Cobalt Chromium alloys contain different amounts of alloying elements; nevertheless. The aim of the current work was to compare the different Cobalt Chromium alloys according to ASTM F or ISO standards in respect to the different alloying elements. Co28Cr6Mo casting alloys according to ASTM F 75 or ISO 5832-4 as well as forging alloy types according to ASTM F 799 and ISO 5832 such as Co20Cr15W10Ni, Co35Ni20Cr, Fe40Co20Cr10Ni, Co20Cr20Ni, and Co28Cr6Mo were analyzed in respect to their element content of Co, Cr, Ni, Mo, Fe, W, and Mn. In 1935 the Cobalt based alloy "Vitallium" Co30Cr5Mo basically used in the aircraft industry was introduced into medicine. The chemical composition of this alloy based on Cobalt showed 30 wt.% Chromium and 5 wt.% Molybdenum. The differentiation using alloy names showed no Nickel information in single alloy names. The information given about different alloys can lead to an unprecise evaluation of histopathological findings in respect to alloys or alloying constituents. Therefore, implant manufacturers should give the exact information about the alloys used and adhere to European law, Euronorm 93/42/EWG.

  4. Excessively High Vapor Pressure of Al-based Amorphous Alloys


    Jeong, Jae; Lee, Sung; Jeon, Je-Beom; Kim, Suk


    Aluminum-based amorphous alloys exhibited an abnormally high vapor pressure at their approximate glass transition temperatures. The vapor pressure was confirmed by the formation of Al nanocrystallites from condensation, which was attributed to weight loss of the amorphous alloys. The amount of weight loss varied with the amorphous alloy compositions and was inversely proportional to their glass-forming ability. The vapor pressure of the amorphous alloys around 573 K was close to the va...

  5. Microstructures and properties of aluminum die casting alloys

    Energy Technology Data Exchange (ETDEWEB)

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


    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.


    Directory of Open Access Journals (Sweden)

    A. V. Alifanov


    Full Text Available The alloys of Fe-Cr-Ni-C system for the purpose of development the economic alloy paramagnetic (not magnetic steels are investigated. A series of alloys are melted for this purpose, deformation is carried out and a structural state was studied.The area for the selection of the chemical composition of the economic alloy steels with stable paramagnetic properties is defined.

  7. Microstructure of Cast Ni-Cr-Al-C Alloy


    Cios G.; Bała P.; Stępień M.; Górecki K.


    Nickel based alloys, especially nickel based superalloys have gained the advantage over other alloys in the field of high temperature applications, and thus become irreplaceable at high temperature creep and aggressive corrosion environments, such as jet engines and steam turbines. However, the wear resistance of these alloys is insufficient at high temperatures. This work describes a microstructure of a new cast alloy. The microstructure consists of γ matrix strengthened by γ’ fine precipita...

  8. Development and Processing Improvement of Aerospace Aluminum Alloys-Development of AL-Cu-Mg-Ag Alloy (2139) (United States)

    Cho, Alex; Lisagor, W. Barry; Bales, Thomas T.


    This final report supplement in presentation format describes a comprehensive multi-tasked contract study to continue the development of the silver bearing alloy now registered as aluminum alloy 2139 by the Aluminum Association. Two commercial scale ingots were processed into nominal plate gauges of two, four and six inches, and were extensively characterized in terms of metallurgical and crystallographic structure, and resulting mechanical properties. This report includes comparisons of the property combinations for this alloy and 2XXX and 7XXX alloys more widely used in high performance applications. Alloy 2139 shows dramatic improvement in all combinations of properties, moreover, the properties of this alloy are retained in all gauge thicknesses, contrary to typical reductions observed in thicker gauges of the other alloys in the comparison. The advancements achieved in this study are expected to result in rapid, widespread use of this alloy in a broad range of ground based, aircraft, and spacecraft applications.

  9. Microstructure and mechanical properties of laser treated aluminium alloys

    NARCIS (Netherlands)

    deHosson, JTM; vanOtterloo, LDM; Noordhuis, J; Mazumder, J; Conde, O; Villar, R; Steen, W


    Al-Cu alloys and an Al-Cu-Mg alloy, Al 2024-T3, were exposed to laser treatments at various scan velocities. In this paper the microstructural features and mechanical properties are reported. As far as the mechanical property of the Al-Cu-Mg alloy is concerned a striking observation is a minimum in

  10. Thixomolded magnesium alloys: Strategic product innovation in automobiles (United States)

    D'Errico, F.; Rivolta, B.; Gerosa, R.; Perricone, G.


    The research on magnesium alloys for structural lightweight applications is today at an embryonic stage, but these alloys offer great potential. Thixomolding of magnesium alloys for automotive applications is promising since the process can be used to manufacture net-shape parts cost-effectively and with high reliability and repeatability.

  11. Lead and lead-based alloys as waste matrix materials

    Energy Technology Data Exchange (ETDEWEB)

    Arustamov, A.E.; Ojovan, M.I.; Kachalov, M.B.


    Metals and alloys with relatively low melting temperatures such as lead and lead-based alloys are considered in Russia as prospective matrices for encapsulation of spent nuclear fuel in containers in preparation for final disposal in underground repositories. Now lead and lead-based alloys are being used for conditioning spent sealed radioactive sources at radioactive waste disposal facilities.

  12. Fatigue Analysis of Magnesium Alloys Components for Car Industry (United States)

    Marsavina, Liviu; Rusu, Lucian; Șerban, Dan Andrei; Negru, Radu Marcel; Cernescu, Anghel


    The use of magnesium alloys in the automotive industry increased in the last decade because of their low weight and relative good mechanical properties. However, the variable loading conditions require a good fatigue behavior. This paper summaries the fatigue properties of magnesium alloys and presents new fatigue curve results for die cast AM50 magnesium alloy.

  13. Sulfuric Acid Corrosion of Low Sb - Pb Battery Alloys | Ntukogu ...

    African Journals Online (AJOL)

    The corrosion properties of low Sb - Pb alloys developed for maintenance free motive power industrial batteries was studied by a bare grid constant current method and compared to those of the conventional Pb- 6% Sb alloy. Low Sb-Pb alloys with Se and As grain refiners were found to have higher corrosion rates than the ...

  14. Effects and mechanisms of grain refinement in aluminium alloys

    Indian Academy of Sciences (India)

    Grain refinement plays a crucial role in improving characteristics and properties of cast and wrought aluminium alloys. Generally Al–Ti and Al–Ti–B master alloys are added to the aluminium alloys to grain refine the solidified product. The mechanism of grain refinement is of considerable controversy in the scientific literature ...

  15. Friction factor of CP aluminium and aluminium–zinc alloys

    Indian Academy of Sciences (India)

    Friction factor has been determined for CP aluminium and aluminium–zinc alloys using ring compression test at different temperatures from 303 K to 773 K. It is found that CP aluminium exhibits sticking whereas Al–Zn alloys do not exhibit sticking at elevated temperatures. Hot working of Al–Zn alloy is easier than that of CP ...

  16. Residual stress state in titanium alloy remelted using GTAW method

    Directory of Open Access Journals (Sweden)

    A. Dudek


    Full Text Available Test materials comprised two-phase titanium alloy Ti6Al4V (Grade5. The surface of the tested alloy was remelted by means of TIG welding method using variable current-voltage parameters. The investigations aimed to determine surface geometry and residual stresses in the remelted surface layer in the investigated alloy.

  17. Friction factor of CP aluminium and aluminium–zinc alloys

    Indian Academy of Sciences (India)

    zinc alloys using ring compression test at different temperatures from 303 K to 773 K. It is found that CP aluminium exhibits stick- ing whereas Al–Zn alloys do not exhibit sticking at elevated temperatures. Hot working of Al–Zn alloy is easier.

  18. 21 CFR 872.3060 - Noble metal alloy. (United States)


    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Noble metal alloy. 872.3060 Section 872.3060 Food... DEVICES DENTAL DEVICES Prosthetic Devices § 872.3060 Noble metal alloy. (a) Identification. A noble metal alloy is a device composed primarily of noble metals, such as gold, palladium, platinum, or silver, that...

  19. 21 CFR 872.3710 - Base metal alloy. (United States)


    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Base metal alloy. 872.3710 Section 872.3710 Food... DEVICES DENTAL DEVICES Prosthetic Devices § 872.3710 Base metal alloy. (a) Identification. A base metal alloy is a device composed primarily of base metals, such as nickel, chromium, or cobalt, that is...

  20. Nanostructured Platinum Alloys for Use as Catalyst Materials (United States)

    Hays, Charles C. (Inventor); Narayan, Sri R. (Inventor)


    A series of binary and ternary Pt-alloys, that promote the important reactions for catalysis at an alloy surface; oxygen reduction, hydrogen oxidation, and hydrogen and oxygen evolution. The first two of these reactions are essential when applying the alloy for use in a PEMFC.

  1. Nitriding of super alloys for enhancing physical properties (United States)

    Purohit, A.


    The invention teaches the improvement of certain super alloys by exposing the alloy to an atmosphere of elemental nitrogen at elevated temperatures in excess of 750/sup 0/C but less than 1150/sup 0/C for an extended duration, viz., by nitriding the surface of the alloy, to establish barrier nitrides of the order of 25 to 100 micrometers thickness. These barrier

  2. 21 CFR 872.3080 - Mercury and alloy dispenser. (United States)


    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Mercury and alloy dispenser. 872.3080 Section 872...) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3080 Mercury and alloy dispenser. (a) Identification. A mercury and alloy dispenser is a device with a spring-activated valve intended to measure and...

  3. Effects and mechanisms of grain refinement in aluminium alloys

    Indian Academy of Sciences (India)


    Abstract. Grain refinement plays a crucial role in improving characteristics and properties of cast and wrought aluminium alloys. Generally Al–Ti and Al–Ti–B master alloys are added to the aluminium alloys to grain refine the solidified product. The mechanism of grain refinement is of considerable controversy in the scientific ...

  4. Preferential dissolution behaviour in Ni–Cr dental cast alloy

    Indian Academy of Sciences (India)


    Ni–Cr–Mo; dental cast alloy; microstructure; corrosion; cyclic polarization. 1. Introduction. Co and Ni based alloys are widely used in dental skeletal structures and orthopedic implants such as screws, pins and plates (Wataha 2000). The advantages of these alloys include low cost of casting, matching thermal expansion.


    The paper describes work, done in 1957-58, in the course of the development of the high-temperature (HT) Ti alloy currently termed BT9(VT9). requirements for the new alloy specified the development of a Ti alloy for forging billets and stamping blanks which at 500 degrees centigrade

  6. Mechanical evaluation of cerebral aneurysm clip scissoring phenomenon: comparison of titanium alloy and cobalt alloy. (United States)

    Tsutsumi, Keiji; Horiuchi, Tetsuyoshi; Hongo, Kazuhiro


    Cerebral aneurysm clip blades crossing during surgery is well known as scissoring. Scissoring might cause rupture of the aneurysm due to laceration of its neck. Although aneurysm clip scissoring is well known, there have been few reports describing the details of this phenomenon. Quasi-scissoring phenomenon was introduced mechanically by rotating the clip head attached to a silicone sheet. The anti-scissoring torque during the twist of the blades was measured by changing the depth and the opening width. The closing force was also evaluated. Sugita straight clips of titanium alloy and cobalt alloy were used in the present study. In both materials, the anti-scissoring torque and the closing force were bigger 3 mm in thickness than 1 mm. The initial closing forces and the anti-scissoring torque values at each rotation angles were increased in proportion to depth. Closing forces of titanium alloy clip were slightly higher than those of cobalt alloy clip. By contrast, anti-scissoring torque values of cobalt alloy clip were bigger than those of titanium alloy clip in all conditions. In condition of 3 mm in thickness and 3 mm in depth, anti-scissoring torque vales of titanium alloy clip decreased suddenly when an angle surpassed 70 degrees. Aneurysm clip scissoring phenomenon tends to occur when clipping the aneurysm neck only with blade tips. Based on the results of this experiment, titanium alloy clip is more prone to scissoring than cobalt alloy clip under the condition that the wide blade separation distance and the shallow blade length.

  7. Welding of gamma titanium aluminide alloys (United States)

    Smashey, Russell W. (Inventor); Kelly, Thomas J. (Inventor); Snyder, John H. (Inventor); Sheranko, Ronald L. (Inventor)


    An article made of a gamma titanium aluminide alloy is welded, as for example in the weld repair of surface cracks, by removing foreign matter from the area to be welded, first stress relieving the article, cooling the entire article to a welding temperature of from about F. to about F., welding a preselected region in an inert atmosphere at the welding temperature, and second stress relieving the article. Welding is preferably accomplished by striking an arc in the preselected region so as to locally melt the alloy in the preselected region, providing a filler metal having the same composition as the gamma titanium aluminide alloy of the article, and feeding the filler metal into the arc so that the filler metal is melted and fused with the article to form a weldment upon solidification.

  8. [Copper and copper alloys. Technology updates]. (United States)

    Loconsolo, V; Crespi, M


    The correlations between copper and copper alloys and human health have been the subject of some recent and extensive scientific researches. The voluntary risks evaluation, which anticipated the EU REACH Directive application, has shown that copper is a "safe" product for human health and for environment. In addition, it could be of great help thanks to its antibacterial properties. Copper tube can contribute in a relevant way to the prevention of water systems pollution by Legionella. Also the spreading of nosocomial infections is significantly contrasted by the use of copper and copper alloys for the production of articles intended for being frequently touched by people. The Environmental Protection Agency of the United States has in fact "registered" as antibacterial over 350 of copper alloys.

  9. Study on Explosive Forming of Aluminum Alloy

    Directory of Open Access Journals (Sweden)

    H Iyama


    Full Text Available Now, the aluminum alloy is often used as auto parts, for example, body, engine. For example, there are the body, a cylinder block, a piston, a connecting rod, interior, exterior parts, etc. These are practical used the characteristic of a light and strong aluminum alloy efficiently. However, although an aluminum alloy is lighter than steel, the elongation is smaller than that. Therefore, in press forming, some problems often occur. We have proposed use of explosive forming, in order to solve this problem. In the explosive forming, since a blank is formed at high speed, a strain rate effect becomes large and it can be made the elongation is larger. Then, in order to clarify this feature, we carried out experimental research and numerical analysis. In this paper, these contents will be discussed.

  10. Joining Techniques for Ferritic ODS Alloys

    Energy Technology Data Exchange (ETDEWEB)

    V.G. Krishnardula; V.G. Krishnardula; D.E. Clark; T.C. Totemeier


    This report presents results of research on advanced joining techniques for ferritic oxide-dispersion strengthened alloys MA956 and PM2000. The joining techniques studied were resistance pressure welding (also known as pressure forge welding), transient liquid phase bonding, and diffusion bonding. All techniques were shown to produce sound joints in fine-grained, unrecrystallized alloys. Post-bond heat treatment to produce a coarse-grained, recrystallized microstructure resulted in grain growth across the bondline for transient liquid phase and diffusion bonds, giving microstructures essentially identical to that of the parent alloy in the recrystallized condition. The effects of bond orientation, boron interlayer thickness, and bonding parameters are discussed for transient liquid phase and diffusion bonding. The report concludes with a brief discussion of ODS joining techniques and their applicability to GEN IV reactor systems.

  11. Magnesium Diecasting Alloys for High Temperature Applications (United States)

    Pekguleryuz, Mihriban O.; Kaya, A. Arslan

    New growth area for automotive use of magnesium is powertrain applications such as the transmission case and engine block. These applications see service conditions in the temperature range of 150-200C under 50-70 MPa of tensile and compressive loads. In addition, metallurgical stability, fatigue resistance, corrosion resistance and castability requirements need to be met. A decade of research and development has resulted in a number of creep- resistant magnesium alloys that are potential candidates for elevated-temperature automotive applications. These alloys are mostly based on rare-earth and alkaline earth element additions to magnesium. This paper gives an overview of the various magnesium alloy systems for use in elevated-temperature applications.

  12. Sputtered Clusters from Niobium-Vanadium Alloys

    DEFF Research Database (Denmark)

    Schou, Jørgen; Hofer, W. O.


    A series of Nb&z.sbnd;V alloys have been irradiated by 6 keV argon ions. Homonuclear and heteronuclear clusters emitted from these alloys have been studied by means of post-ionization and/or secondary ion mass spectrometry. The intensity of clusters of atomic masses up to approximately 300 amu...... was related to the concentrations of Nb and V in the alloys. In addition, the behaviour of polyatomic cluster yields as a function of partial oxygen pressure was studied. At partial pressures larger than approximately 10 6Torr, the yields decreased with increasing partial pressures. By inclusion of the post......-ionized neutrals, the total secondary particle intensity was increased by a factor of 1.5 for clusters up to atomic masses of around 200 amu. Scanning electron microscopy revealed a varied surface topography with large differences from grain to grain for irradiated samples exposed for doses larger than 1018 atoms...

  13. Friction Stir Welding of Steel Alloys (United States)

    Ding, R. Jeffrey; Munafo, Paul M. (Technical Monitor)


    The friction stir welding process has been developed primarily for the welding of aluminum alloys. Other higher melting allows such, as steels are much more difficult to join. Special attention must be given to pin tool material selection and welding techniques. This paper addresses the joining of steels and other high melting point materials using the friction stir welding process. Pin tool material and welding parameters will be presented. Mechanical properties of weldments will also be presented. Significance: There are many applications for the friction stir welding process other than low melting aluminum alloys. The FSW process can be expanded for use with high melting alloys in the pressure vessel, railroad and ship building industries.

  14. Rapid solidification of Nb-base alloys (United States)

    Gokhale, A. B.; Javed, K. R.; Abbaschian, G. J.; Lewis, R. E.


    New Nb-base alloys are of interest for aerospace structural applications at high temperatures, viz, 800 to 1650 C. Fundamental information regarding the effects of rapid solidification in achieving greatly refined microstructures, extended solid solubility, suppression of embrittling equilibrium phases, and formation of new phases is desired in a number of Nb-X alloys. The microstructures and selected properties of Nb-Si and other Nb-base alloys are presented for materials both rapidly quenched from the equilibrium liquidus and rapidly solidified following deep supercooling. Electromagnetic levitation was used to achieve melting and supercooling in a containerless inert gas environment. A variety of solidification conditions were employed including splatting or drop casting of supercooled samples. The morphology and composition of phases formed are discussed in terms of both solidification history and bulk composition.

  15. Seacoast stress corrosion cracking of aluminum alloys (United States)

    Humphries, T. S.; Nelson, E. E.


    The stress corrosion cracking resistance of high strength, wrought aluminum alloys in a seacoast atmosphere was investigated and the results were compared with those obtained in laboratory tests. Round tensile specimens taken from the short transverse grain direction of aluminum plate and stressed up to 100 percent of their yield strengths were exposed to the seacoast and to alternate immersion in salt water and synthetic seawater. Maximum exposure periods of one year at the seacoast, 0.3 or 0.7 of a month for alternate immersion in salt water, and three months for synthetic seawater were indicated for aluminum alloys to avoid false indications of stress corrosion cracking failure resulting from pitting. Correlation of the results was very good among the three test media using the selected exposure periods. It is concluded that either of the laboratory test media is suitable for evaluating the stress corrosion cracking performance of aluminum alloys in seacoast atmosphere.

  16. Cast Aluminum Alloy for High Temperature Applications (United States)

    Lee, Jonathan A.


    Originally developed by NASA as high performance piston alloys to meet U.S. automotive legislation requiring low exhaust emission, the novel NASA alloys now offer dramatic increase in tensile strength for many other applications at elevated temperatures from 450 F (232 C) to about 750 F (400 C). It is an ideal low cost material for cast automotive components such as pistons, cylinder heads, cylinder liners, connecting rods, turbo chargers, impellers, actuators, brake calipers and rotors. It can be very economically produced from conventional permanent mold, sand casting or investment casting, with silicon content ranging from 6% to 18%. At high silicon levels, the alloy exhibits excellent dimensional stability, surface hardness and wear resistant properties.

  17. High-strength iron aluminide alloys

    Energy Technology Data Exchange (ETDEWEB)

    McKamey, C.G.; Maziasz, P.J.


    Past studies have shown that binary Fe{sub 3}Al possesses low creep-rupture strength compared to many other alloys, with creep-rupture lives of less than 5 h being reported for tests conducted at 593{degrees}C and 207 MPa. The combination of poor creep resistance and low room-temperature tensile ductility due to a susceptibility to environmentally-induced dynamic hydrogen embrittlement has limited use of these alloys for structural applications despite their excellent corrosion properties. With regard to the ductility problem, alloy development efforts have produced significant improvements, with ductilities of 10-20% and tensile yield strengths as high as 500 MPa being reported. Likewise, initial improvements in creep resistance have been realized through small additions of Mo, Nb, and Zr.

  18. Irradiation creep of vanadium-base alloys

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, H.; Billone, M.C.; Strain, R.V.; Smith, D.L. [Argonne National Lab., IL (United States); Matsui, H. [Tohoku Univ. (Japan)


    A study of irradiation creep in vanadium-base alloys is underway with experiments in the Advanced Test Reactor (ATR) and the High Flux Isotope Reactor (HFIR) in the United States. Test specimens are thin-wall sealed tubes with internal pressure loading. The results from the initial ATR irradiation at low temperature (200--300 C) to a neutron damage level of 4.7 dpa show creep rates ranging from {approx}0 to 1.2 {times} 10{sup {minus}5}/dpa/MPa for a 500-kg heat of V-4Cr-4Ti alloy. These rates were generally lower than reported from a previous experiment in BR-10. Because both the attained neutron damage levels and the creep strains were low in the present study, however, these creep rates should be regarded as only preliminary. Substantially more testing is required before a data base on irradiation creep of vanadium alloys can be developed and used with confidence.

  19. Effect of alloy recasting on the color of opaque porcelain applied on different dental alloy systems. (United States)

    Yilmaz, Burak; Ozcelik, Tuncer B; Johnston, William M; Kurtulmus-Yilmaz, Sevcan; Company, Andrea M


    The effect of different proportions of recast dental alloys on the color of overlying opaque porcelain (OP) is unknown. The purpose of this study was to compare the color of OP applied on 2 different proportions (50% and 100%) of recast alloys with the color of commercially available shade tabs of OP. Six different metal alloy systems (2 base: Metalloy CC, Cr-Co [B-MCC]; Heraenium NA, Ni-Cr [B-HNA]; 3 noble: Cerapall 2, Pd-Au [N-CP2]; Triumph, Pd-Ag [N-T]; V-Deltaloy, Au-Pd [N-VD]; and 1 high-noble: V-Gnathos Plus, Au-Pt [HN-GP]) were selected for the fabrication of disk-shaped specimens (10 mm in diameter, 1 mm in thickness). Each alloy was divided into 2 subgroups: 50% new alloy with 50% recast alloy (n=3) and 100% recast alloy (n=3). OP (B1) was applied (0.1 mm) to all specimens. The color coordinates (L*, a*, b*) of each specimen and the corresponding commercially available OP shade tab (control) were measured with a spectroradiometer, and color differences between specimens and control group were calculated. Data were statistically analyzed (2-way ANOVA, Ryan-Einot-Gabriel-Welsch multiple range test, α=.05). For each alloy, ΔL*(L(control)(-)L(recastalloy)) values for the 2 subgroups were not statistically different from each other. The Δa* and Δb* of different proportions of N-CP2, B-HNA, N-VD, and HN-GP were not statistically different within the alloys. However, the a* values of 100% recast N-T and B-MCC were significantly closer to the a* values of the control group, and the b* values of 50% recast B-MCC were significantly closer to the b* values of the control group (Pvalues for different proportions of alloys were not statistically different. However, color differences did not meet the criterion of clinical acceptability (ΔE=3.46). According to the results of this study, the different proportions (50% and 100%) of recast alloys used have similar effects on the color of OP. Differences between the final color of OP on the recast alloys used and the

  20. Effects of alloy composition in alleviating embrittlement problems associated with the tantalum alloy T-111 (United States)

    Stephens, J. R.


    The causes of aging embrittlement in T-111 (Ta-8W-2Hf) and the effects of alloy modification were investigated. Results showed that T-111 contains a critical combination of tungsten and hafnium that leads to loss of ductility at -196 C after aging near 1040 C. This appears to occur because tungsten enhances hafnium segregation to grain boundaries and this also leads to increased susceptibility to hydrogen embrittlement. Aging embrittlement was not observed in tantalum alloys with reduced tungsten or hafnium contents; however, most of the alloys studied have lower strengths than T-111 and exhibit susceptibility to hydrogen embrittlement.

  1. Non-alloyed Ni3Al based alloys – preparation and evaluation of mechanical properties

    Directory of Open Access Journals (Sweden)

    J. Malcharcziková


    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.

  2. Formation and characterization of Al–Ti–Nb alloys by electron-beam surface alloying

    Energy Technology Data Exchange (ETDEWEB)

    Valkov, S., E-mail: [Institute of Electronics, Bulgarian Academy of Science, 72 Tzarigradsko Chaussee blvd., 1784 Sofia (Bulgaria); Petrov, P. [Institute of Electronics, Bulgarian Academy of Science, 72 Tzarigradsko Chaussee blvd., 1784 Sofia (Bulgaria); Lazarova, R. [Institute of Metal Science, Equipment and Technologies with Hydro and Aerodynamics Center, Bulgarian Academy of Science, 67 Shipchenski Prohod blvd., 1574 Sofia (Bulgaria); Bezdushnyi, R. [Department of Solid State Physics and Microelectronics, Faculty of Physics, Sofia University “St. Kliment Ohridsky”, 1164 Sofia (Bulgaria); Dechev, D. [Institute of Electronics, Bulgarian Academy of Science, 72 Tzarigradsko Chaussee blvd., 1784 Sofia (Bulgaria)


    Highlights: • Al–Ti–Nb surface alloys have been successfully obtained by electron-beam surface alloying technology. • The alloys consist of (Ti,Nb)Al{sub 3} fractions, distributed in the biphasic structure of (Ti,Nb)Al{sub 3} particles dispersed in α-Al. • The alloying speed does not affect the lattice parameters of (Ti,Nb)Al{sub 3} and, does not form additional stresses, strains etc. • It was found that lower velocity of the specimen motion during the alloying process develops more homogeneous structures. • The measured hardness of (Ti,Nb)Al{sub 3} compound reaches 775 HV[kg/cm{sup 2}] which is much greater than the values of NbAl{sub 3}. - Abstract: The combination of attractive mechanical properties, light weight and resistance to corrosion makes Ti-Al based alloys applicable in many industrial branches, like aircraft and automotive industries etc. It is known that the incorporation of Nb improves the high temperature performance and mechanical properties. In the present study on Al substrate Ti and Nb layers were deposited by DC (Direct Current) magnetron sputtering, followed by electron-beam alloying with scanning electron beam. It was chosen two speeds of the specimen motion during the alloying process: V{sub 1} = 0.5 cm/s and V{sub 2} = 1 cm/s. The alloying process was realized in circular sweep mode in order to maintain the melt pool further. The obtained results demonstrate a formation of (Ti,Nb)Al{sub 3} fractions randomly distributed in biphasic structure of intermetallic (Ti,Nb)Al{sub 3} particles, dispersed in α-Al solid solution. The evaluated (Ti,Nb)Al{sub 3} lattice parameters are independent of the speed of the specimen motion and therefore the alloying speed does not affect the lattice parameters and thus, does not form additional residual stresses, strains etc. It was found that lower velocity of the specimen motion during the alloying process develops more homogeneous structures. The metallographic analyses demonstrate a

  3. Magnesium alloy AZ63A reinforcement by alloying with gallium and using high-disperse ZrO2 particles

    Directory of Open Access Journals (Sweden)

    J. Khokhlova


    Full Text Available The aim of this work was to obtain an experimental magnesium alloy by remelting standard AZ63A alloy with addition of gallium ligatures and ZrO2 particles. This allowed reinforcement of alloy and increase its hardness and Young's modulus. The chemical analysis of this alloy shows two types of structures which are evenly distributed in volume. Thus we can conclude that reinforcing effect is the result of formation of intermetallic phase Mg5-Ga2.

  4. Fast LIBS Identification of Aluminum Alloys

    Directory of Open Access Journals (Sweden)

    Tawfik W.


    Full Text Available Laser-induced breakdown spectroscopy (LIBS has been applied to analysis aluminum alloy targets. The plasma is generated by focusing a 300 mJ pulsed Nd: YAG laser on the target in air at atmospheric pressure. Such plasma emission spectrum was collected using a one-meter length wide band fused-silica optical fiber connected to a portable Echelle spectrometer with intensified CCD camera. Spectroscopic analysis of plasma evolution of laser produced plasmas has been characterized in terms of their spectra, electron density and electron temperature assuming the LTE and optically thin plasma conditions. The LIBS spectrum was optimized for high S/N ratio especially for trace elements. The electron temperature and density were determined using the emission intensity and stark broadening, respectively, of selected aluminum spectral lines. The values of these parameters were found to change with the aluminum alloy matrix, i.e. they could be used as a fingerprint character to distinguish between different aluminum alloy matrices using only one major element (aluminum without needing to analysis the rest of elements in the matrix. Moreover, It was found that the values of T e and N e decrease with increasing the trace elements concentrations in the aluminum alloy samples. The obtained results indicate that it is possible to improve the exploitation of LIBS in the remote on-line industrial monitoring application, by following up only the values of T e and N e for aluminum in aluminum alloys as a marker for the correct alloying using an optical fiber probe.

  5. Ultraprecision microelectroforming of metals and metal alloys (United States)

    Loewe, Holger; Ehrfeld, Wolfgang; Diebel, Joerg


    In recent years, microsystem technology and its growing importance for actuators, sensors, optics and microfluidics, only to name a few, have gained a lot of attention. Specific applications demand fabrication techniques allowing a fast and reliable replication of microstructure products in a variety of materials. An important technique for replication processes of microstructures in many applications of microsystem technology are microelectroforming processes, generating a variety of metals and metal alloys with tailored characteristics. Here, new results in the development of alloys for specific applications as well as their applications are reported: (1) Newly developed alloys: Nickel-iron alloys enable the production of soft magnetic microstructures e.g. for specific applications in microactuators. Nickel-cobalt and Nickel-tungsten alloys have been employed for the manufacture of microstructured tools with excellent mechanical properties regarding wear and mechanical durability. These tools have been applied to hot-embossing and injection molding processes successfully. (2) Microelectroforming within the frame of the LIGA technique allows the manufacturing of extremely precise electrodes with various cross-sections and heights for (mu) - electro discharge machining. The combination of these techniques enables the production of microstructures from non- electrodepositable materials, like stainless steel e.g. for large scale replication processes. (3) The precision of microelectroforming enables the replication of structured surfaces on a nanoscale for molecular microelectronics or special applications. The new types of alloys reported here significantly enlarge the applicability of microelectroforming processes for tool fabrication or direct use. Moreover combining this process with other microstructuring processes like injection molding or (mu) -EDM techniques generates a powerful tool for microsystem technology.

  6. Creep behavior of Zr-Nb alloys

    Energy Technology Data Exchange (ETDEWEB)

    Suh, Yong Chan; Kim, Young Suk; Cheong, Yong Mu; Kwon, Sang Chul; Kim, Sung Soo; Choo, Ki Nam [Korea Atomic Energy Research Institute, Taejeon (Korea)


    The creep characteristics of Zirconium alloy is affected by several parameters. Out-reactor creep increases both with an increasing amount of Nb, Sn and S contained in alpha-Zr and decreases with the increasing volume of alpha-Zr. Especially, the creep of Zr-2.5Nb alloy depends on the solubility of Nb in alpha-Zr, which is associated with the decomposition of beta-Zr. Since Zr of the hcp structure is strongly anisotropic, it shows the characteristics of texture and results in the anisotropy of creep. Due to the circumferential texture of Zr-2.5%Nb alloy (CANDU Pressure tube), the longitudinal slip is easier than the circumferential one, resulting in the high creep rate. The irradiation creep also increases with increasing neutron fluence. The neutron irradiation increases the strength of the zirconium alloys but decreases their creep strength. In contrast to the out-reactor creep, the irradiation creep is little sensitive to temperature, resulting in the lower activation energy. The most important factor to affect the in-reactor and out-reactor creep of niobium containing alloys seems to be the solution hardening by Nb or Sn which is soluble in alpha-zirconium and the texture as well. Irradiation growth is the mechanism which is caused only by the irradiation. It becomes saturated at lower fluence than the critical fluence but beyond it, shows the break-away growth. The onset of accelerated irradiation growth corresponds with the c-dislocation loop formation, though its mechanism needs better understanding. Generally, the irradiation growth of Zr-Nb alloys increases with an increase in fluence, cold working, dislocation, density and temperature, and with a decrease in the grain size. 141 refs., 59 figs., 10 tabs. (Author)

  7. The influence of the pure metal components of four different casting alloys on the electrochemical properties of the alloys. (United States)

    Tuna, Süleyman H; Pekmez, Nuran Ozçiçek; Keyf, Filiz; Canli, Fulya


    The aim of this study was to investigate the influence of the pure metal components of the four different casting alloys on the corrosion behaviors of these alloys tested. Potentiodynamic polarization tests were carried out on four different types of casting alloys and their pure metals at 37 degrees C in an artificial saliva solution. The ions released from the alloys into the solutions during the polarization test were also determined quantitatively using inductively coupled plasma-mass spectrometry (ICP-MS). Ni-Cr (M1) and Co-Cr (M2) alloys had a more homogenous structure than palladium based (M3) and gold based (M4) alloys in terms of the pitting potentials of the casting alloys and those of the pure metals composing the alloys. The total ion concentration released from M3 and M4 was less than from M1 and M2. This may be because M3 and M4 alloys contained noble metals. It was also found that the noble metals in the M3 and M4 samples decreased the current density in the anodic branch of the potentiodynamic polarization curves. In other words, noble metals contributed positively to dental materials. Corrosion resistance of the casting alloys can be affected by the pure metals they are composed of. Au and Pd based noble alloys dissolved less than Ni-Cr and Co-Cr based alloys.

  8. The effect of alloying additives on structure and properties of cast Al-Cu-Si-Mg alloys

    Energy Technology Data Exchange (ETDEWEB)

    Eskin, D.G. [Russian Academy of Sciences, Moscow (Russian Federation). Baikov Inst. of Metall.


    The effect of base and additive alloying elements on the structure and properties of cast Al-Cu-Si-Mg alloys was studied. The mechanical properties at room and elevated temperatures were shown to correlate well with the composition of a supersaturated solid solution and the structure of cast alloys. (orig.)

  9. Mechanical Properties of Aluminum-alloy Rivets (United States)

    Brueggeman, Wm C


    The development of metal construction for aircraft has created a need for accurate and detailed information regarding the strength of riveted joints in aluminum-alloy structures. To obtain this information the National Bureau of Standards in cooperation with the National Advisory Committee for Aeronautics is investigating the strength of riveted joints in aluminum alloys. The strength of riveted joints may be influenced by the form of the head, the ratio of the rivet diameter to the sheet thickness, the driving stress, and other factors. This note gives the results of tests to develop the riveting technique for test specimens and to determine the effects of these factors.

  10. Amorphous Alloy: Promising Precursor to Form Nanoflowerpot

    Directory of Open Access Journals (Sweden)

    Guo Lan


    Full Text Available Nanoporous copper is fabricated by dealloying the amorphous Ti2Cu alloy in 0.03 M HF electrolyte. The pore and ligament sizes of the nanoporous copper can be readily tailored by controlling the dealloying time. The as-prepared nanoporous copper provides fine and uniform nanoflowerpots to grow highly dispersed Au nanoflowers. The blooming Au nanoflowers in the nanoporous copper flowerpots exhibit both high catalytic activity and stability towards the oxidation of glucose, indicating that the amorphous alloys are ideal precursors to form nanoflowerpot which can grow functional nanoflowers.

  11. Pulse reversal plating of nickel alloys

    DEFF Research Database (Denmark)

    Tang, Peter Torben


    Pulse plating has previously been reported to improve the properties of nickel and nickel alloy deposits. Typically, focus has been on properties such as grain size, hardness and smoothness. When pulse plating is to be utilised for microtechnologies such as microelectromechanical systems (MEMS......), internal stress and material distribution are even more important. With baths based upon nickel chloride, and nickel and cobalt chlorides, pulse reversal plating of both pure nickel and nickel-cobalt alloys has been used to fabricate tools for microinjection moulding. Pulse reversal plating of ternary soft...

  12. New developments in rapidly solidified magnesium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Das, S.K. [Allied-Signal, Inc., Morristown, NJ (United States); Chang, C.F. [Allied-Signal, Inc., Morristown, NJ (United States); Raybould, D. [Allied-Signal, Inc., Morristown, NJ (United States); King, J.F. [Magnesium Elektron Ltd., Manchester (United Kingdom); Thistlethwaite, S. [Magnesium Elektron Ltd., Manchester (United Kingdom)


    In the present paper, we will examine the new developments in the rapidly solidified Mg-Al-Zn-Nd (EA55RS) alloy. We shall first briefly review the process scale-up currently employed for producing rapidly solidified magnesium alloys in large quantities, and then discuss the effect of billet size and processing parameters on the mechanical properties of various mill product forms such as extrusions and sheets. The superplastic behavior of EA55RS extrusions and rolled sheets are also discussed. Finally, some results on magnesium metal-matrix composites using rapidly solidified EA55RS matrix powders and SiC particulates are presented. (orig.)

  13. Corrosion resistant alloys for flue gas desulphurisation

    Energy Technology Data Exchange (ETDEWEB)

    Asphahani; Nickerson, J.L. (Haynes International (United States)); Storey, I.J. (Haynes International (United Kingdom))

    Since the mid-seventies, more than 140 field tests have been conducted on several corrosion-resistant alloys in a multitude of flue gas desulphurisation units. In addition, during the eighties, over 30 utilities have installed Hastelloy alloys in the most corrosive conditions in wet scrubbing systems. This article discusses the results from field tests and the experience gained from several installations. The cost effectiveness of thinsheet metallic lining is addressed and the issues of quality control/reliability are reviewed. (6 figures, 5 tables, 7 references). (Author)

  14. Transparent Analogs for Alloy Phase Studies (United States)

    Frazier, D. O.; Smith, James E., Jr.


    Report describes experiments to add information to data base supporting use of transparent, partially miscible liquids and solids as analogs in studies of alloy solidification. Behavior of these materials observed directly while they undergo liquid/liquid and liquid/solid phase transformations. Light-scattering techniques used to determine phase boundaries. Transparent analogs allow observation of both solidification patterns and processes leading to those patterns, whereas metal alloys require tedious post-solidification metallographic analyses because processes not generally observed. Experiments with transparent substances safer and cheaper since conducted at much lower temperatures.

  15. Thermal expansion: Metallic elements and alloys. [Handbook (United States)

    Touloukian, Y. S.; Kirby, R. K.; Taylor, R. E.; Desai, P. D.


    The introductory sections of the work are devoted to the theory of thermal expansion of solids and to methods for the measurement of the linear thermal expansion of solids (X-ray methods, high speed methods, interferometry, push-rod dilatometry, etc.). The bulk of the work is devoted to numerical data on the thermal linear expansion of all the metallic elements, a large number of intermetallics, and a large number of binary alloy systems and multiple alloy systems. A comprehensive bibliography is provided along with an index to the materials examined.

  16. Nodular Corrosion Characteristics of Zirconium Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyun Gil; Jeong, Y. H.; Park, S. Y.; Lee, D. J


    This study was reported the effect of the nodular corrosion on the nuclear reactor environmental along with metallurgical influence, also suggested experimental scheme related to evaluate nodular corrosion characteristics of Zr-1 Nb alloy. Remedial strategies against the nodular corrosion should firstly develop plan to assess the effect of the water quality condition (Oxygen, Hydrogen) as well as the boiling on the nodular corrosion, secondarily establish plan to control heat treatment process to keep a good resistance on nodular corrosion in Zr-1Nb alloy as former western reactor did.

  17. Model for magnetic-nonmagnetic binary alloys

    Energy Technology Data Exchange (ETDEWEB)

    Razafimandimby, H. [Departement de Physique, Universite de Toliara, 601 Toliara (Madagascar); Randrianasoloharisoa, D. [LPMR, Universite d' Antananarivo (Madagascar); Rakotomahevitra, A. [Departement des Sciences Exactes, Universite de Mahajanga, BP 155 (Madagascar); Parlebas, J.C. [IPCMS, UMR 7504 CNRS-Universite Louis Pasteur, 23 rue du Loess, BP 43, 67034 Strasbourg (France)


    An extension of a mean-field approximation (MFA) developed within standard basis operators (SBO) is used to study magnetism in magnetic-nonmagnetic binary alloys. The Curie temperature is calculated from the free energy within the framework of the present approach. The calculated results are in fair agreement with the theoretical results of other research groups for the same problem but utilizing other methods. Finally, the case of NiPt alloys is briefly examined as an example test for the comparison with experiment. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  18. Magnetic susceptibility of Dirac fermions, Bi-Sb alloys, interacting Bloch fermions, dilute nonmagnetic alloys, and Kondo alloys

    Energy Technology Data Exchange (ETDEWEB)

    Buot, Felix A., E-mail: [Computational Materials Science Center, George Mason University, Fairfax, VA 22030 (United States); TCSE Center, Spintronics Group, Physics Department, University of San Carlos, Talamban, Cebu 6000 (Philippines); C& LB Research Institute, Carmen, Cebu 6005 (Philippines); Otadoy, Roland E.S.; Rivero, Karla B. [TCSE Center, Spintronics Group, Physics Department, University of San Carlos, Talamban, Cebu 6000 (Philippines)


    Wide ranging interest in Dirac Hamiltonian is due to the emergence of novel materials, namely, graphene, topological insulators and superconductors, the newly-discovered Weyl semimetals, and still actively-sought after Majorana fermions in real materials. We give a brief review of the relativistic Dirac quantum mechanics and its impact in the developments of modern physics. The quantum band dynamics of Dirac Hamiltonian is crucial in resolving the giant diamagnetism of bismuth and Bi-Sb alloys. Quantitative agreement of the theory with the experiments on Bi-Sb alloys has been achieved, and physically meaningful contributions to the diamagnetism has been identified. We also treat relativistic Dirac fermion as an interband dynamics in uniform magnetic fields. For the interacting Bloch electrons, the role of translation symmetry for calculating the magnetic susceptibility avoids any approximation to second order in the field. The expressions for magnetic susceptibility of dilute nonmagnetic alloys give a firm theoretical foundation of the empirical formulas used in fitting experimental results. The unified treatment of all the above calculations is based on the lattice Weyl-Wigner formulation of discrete phase-space quantum mechanics. For completeness, the magnetic susceptibility of Kondo alloys is also given since Dirac fermions in conduction band and magnetic impurities exhibit Kondo effect.

  19. Heat-Resistance of the Powder Cobalt Alloys Reinforced by Niobium or Titanium Carbide


    Cherepova, T.S.; Dmitrieva, G.P.; V.K. Nosenko


    The characteristics of heat-resistance of powder cobalt alloys at 1100 °C were investigated. These alloys were developed for the protection of workers banding shelves GTE blades from wear. The alloys were prepared by hot pressing powders of cobalt, chromium, aluminum, iron and niobium or titanium carbides. The values of heat resistance alloys containing carbides between 30 and 70% (vol.) depend on the type made of carbide alloys: alloys with titanium carbide superior in heat-resistant alloy o...

  20. The recasting effects on the high gold dental alloy properties

    Directory of Open Access Journals (Sweden)

    Maksimović V.M.


    Full Text Available Noble dental alloys are often reused in dental practice by recasting. The aim of this study was to determine if repeated casting of high gold dental alloys has a detrimental effect on alloy microstructure, type of porosity, structure and microhardness. Results showed that recasting procedure had a strong effect on the change of alloy porosity type. It was also found that alloy microhardness increased with the increase of the number of recasting cycles. At the same time the grain growth and changes of the solid solution phases in the microstructure were observed. [Projekat Ministarstva nauke Republike Srbije, br. III 45012

  1. Challenges for research and development of new aluminum alloys

    Directory of Open Access Journals (Sweden)

    D. Vojtĕch


    Full Text Available Modern trends in research and development of new aluminum alloys are characterized in the present work. Although conventional wrought and casting Al-based alloys show good specific strength, as compared to steels or Ti-based alloys, there is still a potential for significant improvement of their performance. It consists in application of new alloying elements, mainly transition metals, and uncommon processing routes, for example powder metallurgy. By this way, qualitatively new materials with ultra high strength and excellent thermal stability can be developed. However, there are many questions to be answered before new alloys can be competitive to conventional Al-based materials.

  2. Cadmium free lead alloy for reusable radiotherapy shielding. (United States)

    Blackwell, C R; Amundson, K D


    A low melting point cadmium free fusible lead alloy suitable for custom radiotherapy shielding blocks is described. The alloy, referred to here as Alloy-203, differs in composition from the more common Lipowitz's metal (Cerrobend) by being cadmium free, having a slightly higher lead content and a 203 degrees F melting temperature. Attenuation properties have been studied for 4-18 MV X-rays. Alloy-203 has lower transmission than Lipowitz's metal, primarily due to the higher content of lead and bismuth. Daily use for the past 2 years at Mayo Clinic has not indicated any major problems associated with the use of this cadmium free alloy for custom shield fabrication.

  3. A review on hot tearing of magnesium alloys

    Directory of Open Access Journals (Sweden)

    Jiangfeng Song


    Full Text Available Hot tearing is often a major casting defect in magnesium alloys and has a significant impact on the quality of their casting products. Hot tearing of magnesium alloys is a complex solidification phenomenon which is still not fully understood, it is of great importance to investigate the hot tearing behaviour of magnesium alloys. This review attempts to summarize the investigations on hot tearing of magnesium alloys over the past decades. The hot tearing criteria including recently developed Kou's criterion are summarized and compared. The numeric simulation and assessing methods of hot tearing, factors influencing hot tearing, and hot tearing susceptibility (HTS of magnesium alloys are discussed.

  4. Effects of Grain Refining Additions to Aluminum Alloys (United States)

    Gennone, R. J.; Coyle, F. T.; Farrior, G. M.

    An efficient method of controlling the grain-size of commercial aluminum alloys is by continuous additions of grain-refining agents in the form of master-alloy rod which is fed automatically into the launder during casting. The simultaneous addition of titanium and boron in a single rod is more efficient and more economical than separate additions. Response of various alloys to grain refining may be determined using the laboratory test described. Effects of these additions on 6063 alloy are presented; preliminary results on other commercial alloys are included.

  5. Vanadium-base alloys for fusion reactor applications

    Energy Technology Data Exchange (ETDEWEB)

    Smith, D.L.; Loomis, B.A.; Diercks, D.R.


    Vanadium-base alloys offer potentially significant advantages over other candidate alloys as a structural material for fusion reactor first wall/blanket applications. Although the data base is more limited than that for the other leading candidate structural materials, viz., austenitic and ferritic steels, vanadium-base alloys exhibit several properties that make them particularly attractive for the fusion reactor environment. This paper presents a review of the structural material requirements, a summary of the materials data base for selected vanadium-base alloys, and a comparison of projected performance characteristics compared to other candidate alloys. Also, critical research and development (R and D) needs are defined.

  6. The effect of alloying on the ordering processes in near-alpha titanium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Popov, Artemiy, E-mail: [Ural Federal University named after the first President of Russia B.N. Yeltsin, 19 Mira Street, Ekaterinburg 620002 (Russian Federation); Rossina, Natalya [Ural Federal University named after the first President of Russia B.N. Yeltsin, 19 Mira Street, Ekaterinburg 620002 (Russian Federation); Popova, Maria, E-mail: [Ural Federal University named after the first President of Russia B.N. Yeltsin, 19 Mira Street, Ekaterinburg 620002 (Russian Federation)


    The substructure of near-alpha Ti–Al–Sn–Zr–Mo–Si alloys containing up to 12.5 at% aluminum was studied by transmission electron microscopy (TEM). It was shown that long-range order sections are formed at aging temperatures up to 500 °C in alloys, high in aluminum, and the ordered phase is formed by the nucleation and growth mechanism at 700 °C aging temperatures. Causes of changing the phase transformation mechanism have been discussed, and the relationship between the structure and properties of alloys, depending on modes of heat treatment has been analyzed. Also the influence of aluminides and silicides precipitation on the mechanical alloy properties after aging was examined. It was shown that the aluminide formation led to a slight hardening and a significant viscosity decrease. The silicide particles formation reduced the heat resistance properties, due to the depletion of the solid solution by silicon.

  7. Corrosion behavior of friction stir welded AZ31B Mg alloy - Al6063 alloy joint

    Directory of Open Access Journals (Sweden)

    B. Ratna Sunil


    Full Text Available In the present work, AZ31B Mg alloy and Al6063 alloy-rolled sheets were successfully joined by friction stir welding. Microstructural studies revealed a sound joint with good mechanical mixing of both the alloys at the nugget zone. Corrosion performance of the joint was assessed by immersing in 3.5% NaCl solution for different intervals of time and the corrosion rate was calculated. The joint has undergone severe corrosion attack compared with both the base materials (AZ31B and Al6063 alloys. The predominant corrosion mechanism behind the high corrosion rate of the joint was found to be high galvanic corrosion. From the results, it can be suggested that the severe corrosion of dissimilar Mg–Al joints must be considered as a valid input while designing structures intended to work in corroding environment.

  8. Magnesium alloys as implant materials--principles of property design for Mg-RE alloys. (United States)

    Hort, N; Huang, Y; Fechner, D; Störmer, M; Blawert, C; Witte, F; Vogt, C; Drücker, H; Willumeit, R; Kainer, K U; Feyerabend, F


    Magnesium alloys have attracted increasing interest in the past years due to their potential as implant materials. This interest is based on the fact that magnesium and its alloys are degradable during their time of service in the human body. Moreover magnesium alloys offer a property profile that is very close or even similar to that of human bone. The chemical composition triggers the resulting microstructure and features of degradation. In addition, the entire manufacturing route has an influence on the morphology of the microstructure after processing. Therefore the composition and the manufacturing route have to be chosen carefully with regard to the requirements of an application. This paper discusses the influence of composition and heat treatments on the microstructure, mechanical properties and corrosion behaviour of cast Mg-Gd alloys. Recommendations are given for the design of future degradable magnesium based implant materials. Copyright (c) 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  9. Characteristics of 14Cr-ODS ferritic alloy fabricated by mechanically alloying and microwave sintering

    Energy Technology Data Exchange (ETDEWEB)

    Zhenhua, Yao [State Key Laboratory of Materia Processing and Die & Mould Technology, Huazhong University of Science and Technology, Wuhan 430074 (China); Weihao, Xiong, E-mail: [State Key Laboratory of Materia Processing and Die & Mould Technology, Huazhong University of Science and Technology, Wuhan 430074 (China); Bin, Huang; Qingqing, Yang [State Key Laboratory of Materia Processing and Die & Mould Technology, Huazhong University of Science and Technology, Wuhan 430074 (China); Jiang, Jianjun [School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074 (China)


    14Cr-ODS ferritic alloys were fabricated by microwave sintering and conventional vacuum sintering. The results showed that the sintering time could be reduced and the sintering temperature could be decreased effectively by adoption of microwave sintering. The tensile strength of the alloy microwave sintered at 1250 °C and the alloy vacuum sintered at 1350 °C were 691.4 MPa and 521.5 MPa respectively. The superior strength of microwave sintered one would be attributed to finer grain size, which was resulted from the shorter sintering time and lower sintering temperature. The elongation of microwave sintered alloy was worse than that of the vacuum sintering one. Nano-oxide precipitates were dispersed homogeneously in the Fe-based matrix, and their size was mostly ranged from several nm to more than 20 nm.

  10. Alloying effect of copper concentration on the localized corrosion of aluminum alloy for heat exchanger tube (United States)

    Hong, Min-Sung; Park, In-Jun; Kim, Jung-Gu


    This study examined the alloying effect of Cu content on the localized corrosion properties of Al alloy in synthetic acid rain containing 200 ppm of Cl- ion. In aluminum alloy tubes, a small amount of Cu is contained as the additive to improve the mechanical strength or as the impurity. The Cu-containing intermetallic compound, Al2Cu can cause galvanic corrosion because it has more noble potential than Al matrix. Therefore aluminum tube could be penetrated by localized corrosion attack. The results were obtained from electrochemical test, scanning electron microscopy, and time of flight secondary ion mass spectrometry (ToF-SIMS) mapping. Severe localized corrosion was occurred on the Al-0.03 wt% Cu alloy. The negative effect of Cu on the pitting corrosion was attributed to the presence of the Al2Cu precipitates.

  11. Dispersoid reinforced alloy powder and method of making

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Iver E.; Terpstra, Robert L.


    A method of making dispersion-strengthened alloy particles involves melting an alloy having a corrosion and/or oxidation resistance-imparting alloying element, a dispersoid-forming element, and a matrix metal wherein the dispersoid-forming element exhibits a greater tendency to react with a reactive species acquired from an atomizing gas than does the alloying element. The melted alloy is atomized with the atomizing gas including the reactive species to form atomized particles so that the reactive species is (a) dissolved in solid solution to a depth below the surface of atomized particles and/or (b) reacted with the dispersoid-forming element to form dispersoids in the atomized particles to a depth below the surface of said atomized particles. The atomized alloy particles are solidified as solidified alloy particles or as a solidified deposit of alloy particles. Bodies made from the dispersion strengthened alloy particles, deposit thereof, exhibit enhanced fatigue and creep resistance and reduced wear as well as enhanced corrosion and/or oxidation resistance at high temperatures by virtue of the presence of the corrosion and/or oxidation resistance imparting alloying element in solid solution in the particle alloy matrix.

  12. Microstructure and mechanical properties of Mg-Zn-Ag alloys

    Energy Technology Data Exchange (ETDEWEB)

    Park, S.C.; Lim, J.D. [Materials Research Team, R and D Div., Hyundai Motor Co. and Kia Motors Corp., Kyunggi-do (Korea); Eliezer, D. [Dept. of Materials Engineering, Ben-Gurion Univ. of the Negev, Beer-Sheva (Israel); Shin, K.S. [School of Materials Science and Engineering, Seoul National Univ. (Korea); CAAM, POSTECH, Pohang (Korea)


    The majority of Mg components currently in use in the automotive and electronic industries are produced by conventional casting processes. However, there is a strong need to develop new high strength wrought alloys for wide-spread application of Mg alloys in near future. In the present study, new Mg-Zn-Ag alloys were developed and characterized. In order to evaluate the effects of Ag addition on the mechanical properties of the extruded Mg-Zn alloys, the age hardening response and mechanical properties were examined with different amounts of alloying element. The microstructures of the specimens were examined with optical microscopy and transmission electron microscopy. The grain sizes of the alloys in as-extruded condition were markedly reduced with the addition of Ag. The hardness was found to increase more rapidly in the alloys with double aging treatment compared to those with single aging treatment. The peak hardness was also found to be higher in the alloys with double aging treatment. In all heat treatment conditions, the hardness of the Mg-Zn-Ag alloys were found to be higher than those of the Mg-Zn alloys. The addition of Ag to the Mg-Zn alloys increased the tensile strength with a small decrease in tensile elongation in the peak double aging condition. (orig.)

  13. Dispersoid reinforced alloy powder and method of making

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Iver E.; Terpstra, Robert L.


    A method of making dispersion-strengthened alloy particles involves melting an alloy having a corrosion and/or oxidation resistance-imparting alloying element, a dispersoid-forming element, and a matrix metal wherein the dispersoid-forming element exhibits a greater tendency to react with a reactive species acquired from an atomizing gas than does the alloying element. The melted alloy is atomized with the atomizing gas including the reactive species to form atomized particles so that the reactive species is (a) dissolved in solid solution to a depth below the surface of atomized particles and/or (b) reacted with the dispersoid-forming element to form dispersoids in the atomized particles to a depth below the surface of said atomized particles. The atomized alloy particles are solidified as solidified alloy particles or as a solidified deposit of alloy particles. Bodies made from the dispersion strengthened alloy particles, deposit thereof, exhibit enhanced fatigue and creep resistance and reduced wear as well as enhanced corrosion and/or oxidation resistance at high temperatures by virtue of the presence of the corrosion and/or oxidation resistance imparting alloying element in solid solution in the particle alloy matrix.

  14. Development of the advanced nuclear materials -Development of Inconel alloys-

    Energy Technology Data Exchange (ETDEWEB)

    Kuk, Il Hyun; Chang, Jin Sung; Lee, Chang Kyu; Park, Soon Dong; Kim, Woo Kon; Jeong, Man Kyo; Woo, Yoon Myung; Han, Chang Hee [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)


    The performance and the integrity of the steam generator U-tubes directly affects the efficiency and economics of nuclear power plant because they are closely interrelated with the maintenance and repair. Also the steam generator U-tubes have been one of world-wide hot issues in nuclear power plants for long time because of their continuing corrosion-related degradation. Right after stress corrosion cracking of Alloy 600 tubes are reported at primary side, in which the environment is believed to be tightly controlled all the time, in mid 80`s, alloy 690 has started to replace alloy 600. Alloy 690 is basically same with alloy 600 except more Cr content. Firstly minor elements in alloy 690 (C, B, N, Y, Mo) were added or controlled to improve hot workability and corrosion resistance. It would be much more desirable if the mechanism or basic understanding of the degradation phenomena of steam generator U-tubes in operation conditions can be illuminated through the alloy modification research. Alloy 600 tubes which were preproduced in cooperation with Sammi Special Steel were evaluated, being compared with imported one. Also alloy 600 and alloy 690 tubes were produced from Inconel 600 and 690 INCO- forged bar. These will be closely evaluated with purely Korean-made alloy 600 and 690 tubes. 22 tabs., 93 figs., 14 refs. (Author).

  15. Grain Refinement of Permanent Mold Cast Copper Base Alloys

    Energy Technology Data Exchange (ETDEWEB)

    M.Sadayappan; J.P.Thomson; M.Elboujdaini; G.Ping Gu; M. Sahoo


    Grain refinement is a well established process for many cast and wrought alloys. The mechanical properties of various alloys could be enhanced by reducing the grain size. Refinement is also known to improve casting characteristics such as fluidity and hot tearing. Grain refinement of copper-base alloys is not widely used, especially in sand casting process. However, in permanent mold casting of copper alloys it is now common to use grain refinement to counteract the problem of severe hot tearing which also improves the pressure tightness of plumbing components. The mechanism of grain refinement in copper-base alloys is not well understood. The issues to be studied include the effect of minor alloy additions on the microstructure, their interaction with the grain refiner, effect of cooling rate, and loss of grain refinement (fading). In this investigation, efforts were made to explore and understand grain refinement of copper alloys, especially in permanent mold casting conditions.

  16. Heat resistant magnesium alloys for automotive powertrain applications

    Energy Technology Data Exchange (ETDEWEB)

    Anyanwu, I.A.; Gokan, Y.; Nozawa, S.; Kamado, S.; Kojima, Y. [Dept. of Mechanical Engineering, Nagaoka Univ. of Technology, Nagaoka, Niigata (Japan); Takeda, S.; Ishida, T. [Ahresty Corp., Magnesium Products Mfg. Div., Tochigi (Japan)


    The suitability of new Mg-Zn-Al-Ca-RE alloys for automotive power train applications are evaluated. Zinc and aluminum contents of the alloys were systematically varied in order to determine alloys with a combination of good diecasting characteristics and high heat resistance. Addition of large amounts of zinc to the alloys results in the formation of intermetallic compounds that crystallize at lower temperatures relative to the matrix, and consequently, fluidity is improved, but hot tearing occurs during diecasting. However, one of the new alloys, Mg-0.5%Zn-6%Al-1%Ca-3%RE alloy is found to exhibit good diecastability and comparable heat resistance with the conventional aluminum alloy, ADC12 that is currently used for diecasting of automotive powertrain parts. (orig.)

  17. Casting Characteristics of High Cerium Content Aluminum Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Weiss, D; Rios, O R; Sims, Z C; McCall, S K; Ott, R T


    This paper compares the castability of the near eutectic aluminum-cerium alloy system to the aluminum-silicon and aluminum-copper systems. The alloys are compared based on die filling capability, feeding characteristics and tendency to hot tear in both sand cast and permanent mold applications. The castability ranking of the binary Al–Ce systems is as good as the aluminum-silicon system with some deterioration as additional alloying elements are added. In alloy systems that use cerium in combination with common aluminum alloying elements such as silicon, magnesium and/or copper, the casting characteristics are generally better than the aluminum-copper system. In general, production systems for melting, de-gassing and other processing of aluminum-silicon or aluminum-copper alloys can be used without modification for conventional casting of aluminum-cerium alloys.

  18. In vitro and in vivo studies on biodegradable magnesium alloy

    Directory of Open Access Journals (Sweden)

    Lida Hou


    Full Text Available The microstructure, mechanical property, electrochemical behavior and biocompatibility of magnesium alloy (BioDe MSM™ were studied in the present work. The experimental results demonstrated that grain refining induced by extrusion improves the alloy strength significantly from 162 MPa for the as-cast alloy to 241 MPa for the as-extruded one. The anticorrosion properties of the as-extruded alloy also increased. Furthermore, the hemolysis ratio was decreased from 4.7% for the as-cast alloy to 2.9% for the as-extruded one, both below 5%. BioDe MSM™ alloy shows good biocompatibility after being implanted into the dorsal muscle and the femoral shaft of the New Zealand rabbit, respectively, and there are no abnormalities after short-term implantation. In vivo observation indicated that the corrosion rate of this alloy varies with different implantation positions, with higher degradation rate in the femur than in the muscle.

  19. Effects of surface poisons on the oxidation of binary alloys

    Energy Technology Data Exchange (ETDEWEB)

    Hagan, P.S.; Polizzotti, R.S.; Luckman, G.


    A system of reaction-diffusion equations describing the oxidation of binary alloys in environments containing small amounts of surface poisons is analyzed. These poisons reduce the oxygen flux into the alloy, which causes the alloy to oxidize in two stages.During the initial stage, the oxidation reaction occurs in a stationary boundary layer at the alloy surface. Consequently, a thin zone containing a very high concentration of the metal oxide is created at the alloy surface. During the second stage, the oxidation reaction occurs in a moving boundary layer. This leads to a Stefan problem, which is analyzed by using asymptotic and numerical techniques. By comparing the solutions to those of alloys in unpoisoned environments, it is concluded that surface poisons can lead to the formation of protective external oxide scales in alloys which would not normally form such scales. 11 references.

  20. Development of Lead-Free Copper Alloy-Graphite Castings

    Energy Technology Data Exchange (ETDEWEB)

    Rohatgi, P.K. [Univ. of Wisconsin-Milwaukee (US)


    In this project, graphite is used as a substitute for lead in order to maintain the machinability of plumbing components at the level of leaded brass. Graphite dispersed in Cu alloy was observed to impart good machinability and reduce the sizes of chips during machining of plumbing components in a manner similar to lead. Copper alloys containing dispersed graphite particles could be successfully cast in several plumbing fixtures which exhibited acceptable corrosion rate, solderability, platability, and pressure tightness. The power consumption for machining of composites was also lower than that of the matrix alloy. In addition, centrifugally cast copper alloy cylinders containing graphite particles were successfully made. These cylinders can therefore be used for bearing applications, as substitutes for lead-containing copper alloys. The results indicate that copper graphite alloys developed under this DOE project have a great potential to substitute for lead copper alloys in both plumbing and bearing applications.

  1. Biaxial Thermal Creep of Alloy 617 and Alloy 230 for VHTR Applications

    Energy Technology Data Exchange (ETDEWEB)

    Mo, Kun; Lv, Wei; Tung, Hsiao-Ming; Yun, Di; Miao, Yinbin; Lan, Kuan-Che; Stubbins, James F.


    In this study, we employed pressurized creep tubes to investigate the biaxial thermal creep behavior of Inconel 617 (alloy 617) and Haynes 230 (alloy 230). Both alloys are considered to he the primary candidate structural materials for very high-temperature reactors (VITITRs) due to their exceptional high-temperature mechanical properties. The current creep experiments were conducted at 900 degrees C for the effective stress range of 15-35 MPa. For both alloys, complete creep strain development with primary, secondary, and tertiary regimes was observed in all the studied conditions. Tertiary creep was found to he dominant over the entire creep lives of both alloys. With increasing applied creep stress, the fraction of the secondary creep regime decreases. The nucleation, diffusion, and coarsening of creep voids and carbides on grain boundaries were found to be the main reasons for the limited secondary regime and were also found to be the major causes of creep fracture. The creep curves computed using the adjusted creep equation of the form epsilon= cosh 1(1 rt) + P-sigma ntm agree well with the experimental results for both alloys at die temperatures of 850-950 degrees C.

  2. Effect of mechanical alloying on FeCrC reinforced Ni alloys

    Energy Technology Data Exchange (ETDEWEB)

    Yilmaz, S. Osman [Univ. of Namik Kemal, Tekirdag (Turkey); Teker, Tanju [Adiyaman Univ. (Turkey). Dept. of Metallurgical and Materials Engineering; Demir, Fatih [Batman Univ. (Turkey)


    Mechanical alloying (MA) is a powder metallurgy processing technique involving cold welding, fracturing and rewelding of powder particles in a high-energy ball mill. In the present study, the intermetallic matrix composites (IMCs) of Ni-Al reinforced by M{sub 7}C{sub 3} were produced by powder metallurgical routes via solid state reaction of Ni, Al and M{sub 7}C{sub 3} particulates by mechanical alloying processes. Ni, Al and M{sub 7}C{sub 3} powders having 100 μm were mixed, mechanical alloyed and the compacts were combusted in a furnace. The mechanically alloyed (MAed) powders were investigated by X-ray diffraction (XRD), microhardness measurement, optic microscopy (OM), scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS). The presence of the carbides depressed the formation of unwanted NiAl intermetallic phases. The mechanical alloyed M{sub 7}C{sub 3} particles were unstable and decomposed partially within the matrix during alloying and sintering, and the morphology of the composites changed with the dissolution ratio of M{sub 7}C{sub 3} and sintering temperature.

  3. Effect of Al alloying on the martensitic temperature in Ti-Ta shape memory alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ferrari, Alberto; Rogal, Jutta; Drautz, Ralf [Interdisciplinary Centre for Advanced Materials Simulation, Ruhr-Universitaet Bochum (Germany)


    Ti-Ta-based alloys are promising candidates as high temperature shape memory alloys (HTSMAs) for actuators and superelastic applications. The shape memory mechanism involves a martensitic transformation between the low-temperature α'' phase (orthorhombic) and the high-temperature β phase (body-centered cubic). In order to prevent the degradation of the shape memory effect, Ti-Ta needs to be alloyed with further elements. However, this often reduces the martensitic temperature M{sub s}, which is usually strongly composition dependent. The aim of this work is to analyze how the addition of a third element to Ti-Ta alloys affects M{sub s} by means of electronic structure calculations. In particular, it will be investigated how alloying Al to Ti-Ta alters the relative stability of the α'' and β phases. This understanding will help to identify new alloy compositions featuring both a stable shape memory effect and elevated transformation temperatures.

  4. Alloy development and mechanical properties of nickel aluminide (Ni sub 3 Al) alloys

    Energy Technology Data Exchange (ETDEWEB)

    Liu, C.T.; Sikka, V.K.; Horton, J.A.; Lee, E.H.


    This report summarizes recent alloy development of nickel aluminides for structural applications. Boron-doped Ni{sub 3}Al showed severe embrittlement when tested in oxidizing environments above 300{degrees}C. The embrittlement is due to a dynamic effect, which can be alleviated by alloying with 8 at. % Cr. The chromium-modified aluminide alloys possess a good combination of strength and ductility for use at temperatures to 1000{degrees}C. The hot ductility and fabricability of the aluminide alloys can be substantially improved by reducing the zirconium content to below 0.35 at. %. Material processing of large aluminide heats has been demonstrated by both conventional and innovative techniques. Mechanical properties of the aluminide alloys were characterized at temperatures to 1200{degrees}C. Grain size, which is the main difference between the materials produced by the various processing techniques, is the major metallurgical parameter that strongly influences the mechanical properties of the aluminide alloys. 35 refs., 20 figs., 11 tabs.

  5. Magnetic field-induced solvothermal synthesis of one-dimensional assemblies of Ni-Co alloy microstructures

    National Research Council Canada - National Science Library

    Hu, Ming Jun; Lin, Bin; Yu, Shu Hong


    One-dimensional magnetic Ni-Co alloy microwires with different microstructures and differently shaped building blocks including spherical particles, multilayer stacked alloy plates, and alloy flowers...

  6. Reduction in Defect Content of ODS Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ritherdon, J


    The work detailed within this report is a continuation of earlier work carried out under contract number 1DX-SY382V. The earlier work comprises a literature review of the sources and types of defects found principally in Fe-based ODS alloys as well as experimental work designed to identify defects in the prototype ODS-Fe{sub 3}Al alloy, deduce their origins and to recommend methods of defect reduction. The present work is an extension of the experimental work already reported and concentrates on means of reduction of defects already identified rather than the search for new defect types. This report also includes results gathered during powder separation trials, conducted by the University of Groningen, Netherlands and coordinated by the University of Liverpool, involving the separation of different metallic powders in terms of their differing densities. The scope and objectives of the present work were laid out in the technical proposal ''Reduction in Defect Content in ODS Alloys-III''. All the work proposed in the ''Statement of Work'' section of the technical proposal has been carried out and all work extra to the ''Statement of Work'' falls within the context of an ODS-Fe{sub 3}Al alloy of improved overall quality and potential creep performance in the consolidated form. The outturn of the experimental work performed is reported in the following sections.

  7. High temperature alloy chloridation at 850 C

    Energy Technology Data Exchange (ETDEWEB)

    Chevalier, S.; Bekaddour, A. [Laboratoire de Recherches sur la Reactivite des Solides, UMR 5613 CNRS, Universite de Bourgogne, 9 avenue Alain Savary, 21078 Dijon (France); Ched' Homme, S. [DTM/SRPU/LPPU, CEA Valduc, 21120 Is-sur-Tille (France); Amilain-Basset, K.; Buisson, L. [Interface Caracterisation des Materiaux, Universite de Bourgogne, 21078 Dijon (France)


    The resistance of eight alloys against chloridation was tested at 850 C in Ar/Cl{sub 2} (2.5% Cl{sub 2}) for 15 min. Pre-oxidation treatments were performed for 1 h and 8 h at 850 C in order to produce a thin, adherent and protective oxide scale able to improve the chloridation behaviour of the tested materials. The chloridised sample morphologies were compared to the morphologies observed on the non pre-oxidised samples. The alloys containing a large amount of iron did not exhibit any chloridation resistance, even after pre-oxidation, and were severely damaged. The nickel based alloys gave interesting results but were also attacked by chloride, probably by the ''active oxidation'' mechanism. The duration of the pre-oxidation treatment plays an important role, since the 8 h pre-oxidation appears more beneficial than the 1 h pre-oxidation, to delay the chloridation, probably because of the best quality of the oxide layer grown during 8 h. For the nickel based materials, the effects of chloride appear less severe than for the iron-based alloys, but are not stopped. The ''active oxidation'' mechanism is proposed to be responsible for the degradation of the tested materials. (Abstract Copyright [2007], Wiley Periodicals, Inc.)

  8. Discontinuous precipitation in copper base alloys

    Indian Academy of Sciences (India)


    Abstract. Discontinuous precipitation (DP) is associated with grain boundary migration in the wake of which alternate plates of the precipitate and the depleted matrix form. Some copper base alloys show DP while others do not. In this paper the misfit strain parameter, η, has been calculated and predicted that if.

  9. Zirconium modified nickel-copper alloy (United States)

    Whittenberger, J. D. (Inventor)


    An improved material for use in a catalytic reactor which reduces nitrogen oxide from internal combustion engines is in the form of a zirconium-modified, precipitation-strengthened nickel-copper alloy. This material has a nominal composition of Ni-30 Cu-0.2 Zr and is characterized by improved high temperature mechanical properties.

  10. Dendritic Solidification in a Copper Nickel Alloy


    DÜNDAR, Sacit


    The distribution of nickel in dendrite arms and in interdendritic regions of copper-10% nickel alloy solidified under production conditions designed to provide 4 different cooling rates was investigated. The results indicate that at different rates of solidification undercooling, diffusion and convection mechanisms affect the microsegregation of nickel and copper in the cast materials to various extents.

  11. Materials data handbook on Inconel Alloy 718 (United States)

    Muraca, R. F.; Whittick, J. S.


    Handbook is divided into twelve chapters. Scope of information presented includes physical- and mechanical-property data at cryogenic, ambient, and elevated temperatures. This is supplemented with useful information in such areas as material procurement, metallurgy of alloy, corrosion, environmental effect, fabrication, and joining techniques. Design data are presented, as available.

  12. In vivo effects of dental casting alloys

    Czech Academy of Sciences Publication Activity Database

    Venclíková, Z.; Benada, Oldřich; Bártová, J.; Joska, L.; Mrklas, L.; Procházková, J.; Stejskal, V.D.M.; Podzimek, Š.


    Roč. 27, č. 1 (2006), s. 25-32 ISSN 0172-780X R&D Projects: GA MZd NK7437 Institutional research plan: CEZ:AV0Z50200510 Keywords : dental alloys * metals * gingiva Subject RIV: EE - Microbiology, Virology Impact factor: 0.924, year: 2006

  13. Laser polishing of additive manufactured Ti alloys (United States)

    Ma, C. P.; Guan, Y. C.; Zhou, W.


    Laser-based additive manufacturing has attracted much attention as a promising 3D printing method for metallic components in recent years. However, surface roughness of additive manufactured components has been considered as a challenge to achieve high performance. In this work, we demonstrate the capability of fiber laser in polishing rough surface of additive manufactured Ti-based alloys as Ti-6Al-4V and TC11. Both as-received surface and laser-polished surfaces as well as cross-section subsurfaces were analyzed carefully by White-Light Interference, Confocal Microscope, Focus Ion Beam, Scanning Electron Microscopy, Energy Dispersive Spectrometer, and X-ray Diffraction. Results revealed that as-received Ti-based alloys with surface roughness more than 5 μm could be reduce to less than 1 μm through laser polishing process. Moreover, microstructure, microhardness and wear resistance of laser-polished zone was investigated in order to examine the thermal effect of laser polishing processing on the substrate of additive manufactured Ti alloys. This proof-of-concept process has the potential to effectively improve the surface roughness of additive manufactured metallic alloy by local polishing method without damage to the substrate.

  14. Deformation heterogeneity in cellular Al alloys

    Energy Technology Data Exchange (ETDEWEB)

    Bastawros, A.-F. [Iowa State Univ., Ames, IA (United States). Dept. of Aerospace Engineering and Mechanics; Evans, A.G. [Princeton Univ., NJ (United States). Materials Inst.


    Cell ellipticity and non-planar membranes are thought to be dominant degradation factors of cellular metals. The mechanisms operating at the cell/membrane level in both closed and open cell Al alloys have been established by following the evolution of deformation with cell-level resolution using digital image correlation analysis. (orig.)

  15. Nickel-titanium alloys: a systematic review

    Directory of Open Access Journals (Sweden)

    Marcelo do Amaral Ferreira


    Full Text Available OBJECTIVE: A systematic review on nickel-titanium wires was performed. The strategy was focused on Entrez-PubMed-OLDMEDLINE, Scopus and BioMed Central from 1963 to 2008. METHODS: Papers in English and French describing the behavior of these wires and laboratorial methods to identify crystalline transformation were considered. A total of 29 papers were selected. RESULTS: Nickel-titanium wires show exceptional features in terms of elasticity and shape memory effects. However, clinical applications request a deeper knowledge of these properties in order to allow the professional to use them in a rational manner. In addition, the necessary information regarding each alloy often does not correspond to the information given by the manufacturer. Many alloys called "superelastic" do not present this effect; they just behave as less stiff alloys, with a larger springback if compared to the stainless steel wires. CONCLUSIONS: Laboratory tests are the only means to observe the real behavior of these materials, including temperature transition range (TTR and applied tensions. However, it is also possible to determine in which TTR these alloys change the crystalline structure.

  16. Structure of Liquid Na-K Alloys

    NARCIS (Netherlands)

    Alblas, B.P.; Lugt, W. van der; Valk, H.J.L. van der; Hosson, J.Th.M. De; Dijk, C. van


    X-ray and neutron diffraction data are presented for a number of liquid Na-K alloys covering the whole composition range. Additionally, for the composition 50 at.% Na - 50 at.% K, a computer experiment in molecular dynamics has been carried out. An attempt is made to analyze the results in terms of

  17. Cytotoxicity of titanium and titanium alloying elements. (United States)

    Li, Y; Wong, C; Xiong, J; Hodgson, P; Wen, C


    It is commonly accepted that titanium and the titanium alloying elements of tantalum, niobium, zirconium, molybdenum, tin, and silicon are biocompatible. However, our research in the development of new titanium alloys for biomedical applications indicated that some titanium alloys containing molybdenum, niobium, and silicon produced by powder metallurgy show a certain degree of cytotoxicity. We hypothesized that the cytotoxicity is linked to the ion release from the metals. To prove this hypothesis, we assessed the cytotoxicity of titanium and titanium alloying elements in both forms of powder and bulk, using osteoblast-like SaOS(2) cells. Results indicated that the metal powders of titanium, niobium, molybdenum, and silicon are cytotoxic, and the bulk metals of silicon and molybdenum also showed cytotoxicity. Meanwhile, we established that the safe ion concentrations (below which the ion concentration is non-toxic) are 8.5, 15.5, 172.0, and 37,000.0 microg/L for molybdenum, titanium, niobium, and silicon, respectively.

  18. Hydrogenation properties of Mg-Al alloys

    DEFF Research Database (Denmark)

    Andreasen, Anders


    . 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...

  19. Gold-nickel-titanium brazing alloy (United States)

    Mizuhara, Howard


    A brazing alloy in accordance with this invention has the following composition, by weight: 91 to 99% gold, 0.5 to 7% nickel; 0.10 to 2% titanium. Alternatively, with palladium present, the composition is as follows, by weight: 83 to 96% gold; 3 to 10% palladium; 0.5 to 5% nickel; 0.10 to 2% titanium.

  20. Discontinuous precipitation in copper base alloys

    Indian Academy of Sciences (India)

    Discontinuous precipitation (DP) is associated with grain boundary migration in the wake of which alternate plates of the precipitate and the depleted matrix form. Some copper base alloys show DP while others do not. In this paper the misfit strain parameter, , has been calculated and predicted that if 100 > ± 0.1, DP is ...

  1. Microstructure Development during Solidification of Aluminium Alloys

    NARCIS (Netherlands)

    Ruvalcaba Jimenez, D.G.


    This Thesis demonstrates studies on microstructure development during the solidification of aluminium alloys. New insights of structure development are presented here. Experimental techniques such as quenching and in-situ High-brilliance X-ray microscopy were utilized to study the microstructure

  2. Shape memory alloys – characterization techniques

    Indian Academy of Sciences (India)

    A space-rotating platform is designed and fabricated, using an actuator of shape memory spring, for obtaining controlled rotations. The efficiency and the reliability of this actuator has been tested, over a million thermal cycles. Keywords. Shape memory alloys; characterization techniques; austenitic phase; martensitic phase;.

  3. Corrosion of carbon-alloyed iron aluminides

    Indian Academy of Sciences (India)


    Corrosion of carbon-alloyed iron aluminides. M SEN, R BALASUBRAMANIAM* and A V RAMESH KUMAR†. Department of Materials and Metallurgical Engineering, Indian Institute of Technology, Kanpur 208 016, India. †Defence Materials Stores and Research Development Establishment, Kanpur 208 013, India.

  4. Biocompatibility of nickel and cobalt dental alloys. (United States)

    Grimaudo, N J


    Allergies related to dentistry generally constitute delayed hypersensitivity reactions to specific dental materials. Although true allergic hypersensitivity to dental materials is rare, certain products have definite allergenic properties. This review presents a comparative evaluation of the biocompatibility of nickel-chromium, nickel-chromium-beryllium, and cobalt-chromium alloys.

  5. Antiferromagnetism in chromium alloy single crystals

    DEFF Research Database (Denmark)

    Bjerrum Møller, Hans; Trego, A.L.; Mackintosh, A.R.


    The antiferromagnetism of single crystals of dilute alloys of V, Mn and Re in Cr has been studied at 95°K and 300°K by neutron diffraction. The addition of V causes the diffraction peaks to decrease in intensity and move away from (100), while Mn and Re cause them to increase and approach (100) s...

  6. Localized Corrosion of Alloy 22 -Fabrication Effects-

    Energy Technology Data Exchange (ETDEWEB)

    Rebak, R B


    This report deals with the impact of fabrication processes on the localized corrosion behavior of Alloy 22 (N06022). The four fabrication processes that were analyzed are: (1) Surface stress mitigation of final closure weld, (2) Manufacturing of the mockup container, (3) Black annealing of the container and (4) Use of different heats of Alloy 22 for container fabrication. Immersion and Electrochemical tests performed in the laboratory are generally aggressive and do not represent actual repository environments in Yucca Mountain. For example, to determine the intergranular attack in the heat affected zone of a weldment, tests are conducted in boiling acidic and oxidizing solutions according to ASTM standards. These solutions are used to compare the behavior of differently treated metallic coupons. Similarly for electrochemical tests many times pure sodium chloride or calcium chloride solutions are used. Pure chloride solutions are not representative of the repository environment. (1) Surface Stress Mitigation: When metallic plates are welded, for example using the Gas Tungsten Arc Welding (GTAW) method, residual tensile stresses may develop in the vicinity of the weld seam. Processes such as Low Plasticity Burnishing (LPB) and Laser Shock Peening (LSP) could be applied locally to eliminate the residual stresses produced by welding. In this study, Alloy 22 plates were welded and then the above-mentioned surface treatments were applied to eliminate the residual tensile stresses. The aim of the current study was to comparatively test the corrosion behavior of as-welded (ASW) plates with the corrosion behavior of plates with stress mitigated surfaces. Immersion and electrochemical tests were performed. Results from both immersion and electrochemical corrosion tests show that the corrosion resistance of the mitigated plates was not affected by the surface treatments applied. (2) Behavior of Specimens from a Mockup container: Alloy 22 has been extensively tested for

  7. Ternary alloy nanocatalysts for hydrogen evolution reaction

    Indian Academy of Sciences (India)

    Ternary alloy nanocatalysts for hydrogen evolution reaction. SOUMEN SAHA1, SONALIKA VAIDYA2, KANDALAM V RAMANUJACHARY3,. SAMUEL E LOFLAND4 and ASHOK K GANGULI1,2,∗. 1Department of Chemistry, Indian Institute of Technology, Hauz Khas, New Delhi 110016, India. 2Institute of Nano Science and ...

  8. Nuclear magnetic resonance on amorphous alloys

    Energy Technology Data Exchange (ETDEWEB)

    Khan, H.R. (Forschungsinstitut fuer Edelmetalle und Metallchemie, Schwaebisch Gmuend (Germany, F.R.)); Lueders, K. (Freie Univ. Berlin (Germany, F.R.). Inst. fuer Atom- und Festkoerperphysik)


    NMR work on nonmagnetic metallic glasses is summarized. A detailed review is given of their fundamental properties by means of Knight shift, lineshape, and spin-lattice relaxation rate measurements. The alloys in consideration are Ni-Pt-P,Ni-Pd-P, Ni-Cu-P,Ni-P,Ni-P-B,Mo-Ru-P,Be-Nb-Zr, and Be-Mo-Zr.

  9. Reduction in Defect Content in ODS Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ritherdon, J.; Jones, A.R.


    The work detailed within this report is a continuation of earlier work that was carried out under contract number IDX-SY382V. The earlier work comprised a literature review of the sources and types of defects found principally in Fe-based ODS alloys together with a series of experiments designed to identify defects in ODS Fe{sub 3}Al material and recommend methods of defect reduction. Defects found in the Mechanically Alloyed (MA) ODS Fe{sub 3}Al included regions of incomplete MA, porosity, intrusions and fine-grained stringers. Some defects tended to be found in association with one another e.g. intrusions and fine-grained stringers. Preliminary powder separation experiments were also performed. The scope and objectives of the present work were laid out in the technical proposal ``Reduction in Defect Content in ODS Alloys--II'' which formed the basis of amendment 3 of the current contract. The current studies were devised in the context of the preceding work with a view to extending and concluding certain experiments while exploring new avenues of investigation of defect control and reduction where appropriate. All work proposed was within the context of achieving an ODS Fe{sub 3}Al alloy of improved overall quality and potential creep performance (particularly) in the consolidated, release condition. The interim outturn of the experimental work performed is also reported.

  10. Laser alloyed Al-Ni-Fe coatings

    CSIR Research Space (South Africa)

    Pityana, SL


    Full Text Available The aim of this work was to produce crack-free thin surface layers consisting of binary (Al-Ni, Al-Fe) and ternary (Al-Ni-Fe) intermetallic phases by means of a high power laser beam. The laser surface alloying was carried out by melting Fe and Ni...

  11. Atomic displacements in bcc dilute alloys

    Indian Academy of Sciences (India)

    Home; Journals; Pramana – Journal of Physics; Volume 68; Issue 4. Atomic displacements in bcc ... metal (TM) dilute alloys. We have calculated the atomic displacements in bcc (V, Cr, Fe, Nb, Mo, Ta and W) transition metals (TMs) due to 3d, 4d and 5d TMs at the substitutional site using the Kanzaki lattice static method.

  12. Electrocatalytic Alloys for CO2 Reduction. (United States)

    He, Jingfu; Johnson, Noah J J; Huang, Aoxue; Berlinguette, Curtis P


    Electrochemically reducing CO2 using renewable energy is a contemporary global challenge that will only be met with electrocatalysts capable of efficiently converting CO2 into fuels and chemicals with high selectivity. Although many different metals and morphologies have been tested for CO2 electrocatalysis over the last several decades, relatively limited attention has been committed to the study of alloys for this application. Alloying is a promising method to tailor the geometric and electric environments of active sites. The parameter space for discovering new alloys for CO2 electrocatalysis is particularly large because of the myriad products that can be formed during CO2 reduction. In this Minireview, mixed-metal electrocatalyst compositions that have been evaluated for CO2 reduction are summarized. A distillation of the structure-property relationships gleaned from this survey are intended to help in the construction of guidelines for discovering new classes of alloys for the CO2 reduction reaction. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Theoretical Studies of Hydrogen Storage Alloys.

    Energy Technology Data Exchange (ETDEWEB)

    Jonsson, Hannes


    Theoretical calculations were carried out to search for lightweight alloys that can be used to reversibly store hydrogen in mobile applications, such as automobiles. Our primary focus was on magnesium based alloys. While MgH{sub 2} is in many respects a promising hydrogen storage material, there are two serious problems which need to be solved in order to make it useful: (i) the binding energy of the hydrogen atoms in the hydride is too large, causing the release temperature to be too high, and (ii) the diffusion of hydrogen through the hydride is so slow that loading of hydrogen into the metal takes much too long. In the first year of the project, we found that the addition of ca. 15% of aluminum decreases the binding energy to the hydrogen to the target value of 0.25 eV which corresponds to release of 1 bar hydrogen gas at 100 degrees C. Also, the addition of ca. 15% of transition metal atoms, such as Ti or V, reduces the formation energy of interstitial H-atoms making the diffusion of H-atoms through the hydride more than ten orders of magnitude faster at room temperature. In the second year of the project, several calculations of alloys of magnesium with various other transition metals were carried out and systematic trends in stability, hydrogen binding energy and diffusivity established. Some calculations of ternary alloys and their hydrides were also carried out, for example of Mg{sub 6}AlTiH{sub 16}. It was found that the binding energy reduction due to the addition of aluminum and increased diffusivity due to the addition of a transition metal are both effective at the same time. This material would in principle work well for hydrogen storage but it is, unfortunately, unstable with respect to phase separation. A search was made for a ternary alloy of this type where both the alloy and the corresponding hydride are stable. Promising results were obtained by including Zn in the alloy.

  14. Utilization of Copper Alloys for Marine Applications (United States)

    Drach, Andrew

    Utilization of copper alloy components in systems deployed in marine environment presents potential improvements by reducing maintenance costs, prolonging service life, and increasing reliability. However, integration of these materials faces technological challenges, which are discussed and addressed in this work, including characterization of material performance in seawater environment, hydrodynamics of copper alloy components, and design procedures for systems with copper alloys. To characterize the hydrodynamic behavior of copper alloy nets, mesh geometry of the major types of copper nets currently used in the marine aquaculture are analyzed and formulae for the solidity and strand length are proposed. Experimental studies of drag forces on copper alloy net panels are described. Based on these studies, empirical values for normal drag coefficients are proposed for various types of copper netting. These findings are compared to the previously published data on polymer nets. It is shown that copper nets exhibit significantly lower resistance to normal currents, which corresponds to lower values of normal drag coefficient. The seawater performance (corrosion and biofouling) of copper alloys is studied through the field trials of tensioned and untensioned specimens in a one-year deployment in the North Atlantic Ocean. The corrosion behavior is characterized by weight loss, optical microscopy, and SEM/EDX analyses. The biofouling performance is quantified in terms of the biomass accumulation. To estimate the effects of stray electrical currents on the seawater corrosion measurements, a low cost three-axis stray electric current monitoring device is designed and tested both in the lab and in the 30-day field deployment. The system consists of a remotely operated PC with a set of pseudo-electrodes and a digital compass. The collected data is processed to determine magnitudes of AC and DC components of electric field and dominant AC frequencies. Mechanical behavior of

  15. Oxidation Behavior of TiAl-Based Alloy Modified by Double-Glow Plasma Surface Alloying with Cr-Mo (United States)

    Wei, Xiangfei; Zhang, Pingze; Wang, Qiong; Wei, Dongbo; Chen, Xiaohu


    A Cr-Mo alloyed layer was prepared on a TiAl-based alloy using plasma surface alloying technique. The isothermal oxidation kinetics of the untreated and treated samples was examined at 850 °C. The microstructure and phase composition of the alloyed layer were analyzed by scanning electron microscope (SEM), energy dispersive spectrometer (EDS) and X-ray powder diffraction (XRD). The morphology and constituent of the oxide scales were also analyzed. The results indicated that the oxidation resistance of TiAl was improved significantly after the alloying treatment. The oxide scale eventually became a mixture of Al2O3, Cr2O3 and TiO2. The oxide scale was dense and integrated throughout the oxidation process. The improvement was mainly owing to the enhancing of scale adhesion and the preferential oxidation of aluminum brought by the alloying effect for TiAl-based alloy.

  16. Fast LIBS Identification of Aluminum Alloys

    Directory of Open Access Journals (Sweden)

    Tawfik W.


    Full Text Available Laser-induced breakdown spectroscopy (LIBS has been applied to analysis aluminum alloy targets. The plasma is generated by focusing a 300 mJ pulsed Nd: YAG laser on the target in air at atmospheric pressure. Such plasma emission spectrum was collected using a one-meter length wide band fused-silica optical fiber connected to a portable Echelle spectrometer with intensified CCD camera. Spectroscopic analysis of plasma evolution of laser produced plasmas has been characterized in terms of their spectra, electron density and electron temperature assuming the LTE and optically thin plasma conditions. The LIBS spectrum was optimized for high S/N ratio especially for trace elements. The electron temperature and density were determined using the emission intensity and stark broadening, respectively, of selected aluminum spectral lines. The values of these parameters were found to change with the aluminum alloy matrix, i.e. they could be used as a fingerprint character to distinguish between different aluminum alloy matrices using only one major element (aluminum without needing to analysis the rest of elements in the matrix. Moreover, It was found that the values of T(e and N(e decrease with increasing the trace elements concentrations in the aluminum alloy samples. The obtained results indicate that it is possible to improve the exploitation of LIBS in the remote on-line industrial monitoring application, by following up only the values of T(e and N(e for the aluminum in aluminum alloys using an optical fiber probe.

  17. Cast B2-phase iron-aluminum alloys with improved fluidity (United States)

    Maziasz, Philip J.; Paris, Alan M.; Vought, Joseph D.


    Systems and methods are described for iron aluminum alloys. A composition includes iron, aluminum and manganese. A method includes providing an alloy including iron, aluminum and manganese; and processing the alloy. The systems and methods provide advantages because additions of manganese to iron aluminum alloys dramatically increase the fluidity of the alloys prior to solidification during casting.

  18. Recycling of Glass Fibre Reinforced Aluminium Laminates and Silicon Removal from Aerospace Al Alloy

    NARCIS (Netherlands)

    Zhu, G.


    Aerospace aluminium alloys (7xxx and 2xxx series Al alloy) is one of the important Al alloys in our life. The recycling of aerospace Al alloy plays a significant role in sustainable development of Al industry. The fibre reinforced metal laminates GLARE including 67 wt.% 2024 Al alloy was used as

  19. Evaluation of flexural bond strength of porcelain to used nickel-chromium alloy in various percentages

    Directory of Open Access Journals (Sweden)

    VNV Madhav


    Fresh nickel-chromium alloy shows the greatest porcelain adherence.There is no significant change in bond strength of ceramic to alloy with up to 75% of used nickel-chromium alloy.At least 25%- of new alloy should be added when recycled nickel-chromium alloy is being used for metal ceramic restorations.

  20. Comparative study of electron and laser beam surface alloying (United States)

    Valkov, Stefan Ts.; Petrov, Peter, Iv.; Lazarova, Rumiana L.


    High intensity energy fluxes, such as electron beams and laser beams are widely used for surface alloying of metals and alloys. These technologies are able to cause the formation of the so called melt pool where the alloying elements interact each other. It is known that the homogenization of the surface alloy can be explained by intense Marangoni convection, caused by the high temperature gradient in the melt pool. The convection is inversely to the speed of the specimen motion during the alloying process and therefore, the choice of low alloying velocity will reflect on more homogeneous structure of the obtained alloy. In this study, a comparison of the structure and properties of electron and laser beam surface alloying of aluminium with niobium was conducted. The phase composition of the alloyed layers was determined by XRD (X-ray diffraction) with CuKα radiation. The microstructure was studied by SEM (Scanning Electron Microscopy). Chemical analysis was carried out using an EDX electron probe microanalyser. The microhardness of the obtained samples is also measured and compared with respect to the technology of the formation of each surface alloy.

  1. New Developments of Ti-Based Alloys for Biomedical Applications. (United States)

    Li, Yuhua; Yang, Chao; Zhao, Haidong; Qu, Shengguan; Li, Xiaoqiang; Li, Yuanyuan


    Ti-based alloys are finding ever-increasing applications in biomaterials due to their excellent mechanical, physical and biological performance. Nowdays, low modulus β-type Ti-based alloys are still being developed. Meanwhile, porous Ti-based alloys are being developed as an alternative orthopedic implant material, as they can provide good biological fixation through bone tissue ingrowth into the porous network. This paper focuses on recent developments of biomedical Ti-based alloys. It can be divided into four main sections. The first section focuses on the fundamental requirements titanium biomaterial should fulfill and its market and application prospects. This section is followed by discussing basic phases, alloying elements and mechanical properties of low modulus β-type Ti-based alloys. Thermal treatment, grain size, texture and properties in Ti-based alloys and their limitations are dicussed in the third section. Finally, the fourth section reviews the influence of microstructural configurations on mechanical properties of porous Ti-based alloys and all known methods for fabricating porous Ti-based alloys. This section also reviews prospects and challenges of porous Ti-based alloys, emphasizing their current status, future opportunities and obstacles for expanded applications. Overall, efforts have been made to reveal the latest scenario of bulk and porous Ti-based materials for biomedical applications.

  2. Damage buildup and edge dislocation mobility in equiatomic multicomponent alloys

    Energy Technology Data Exchange (ETDEWEB)

    Granberg, F., E-mail: [Department of Physics, P.O. Box 43, FIN-00014 University of Helsinki (Finland); Djurabekova, F. [Department of Physics, P.O. Box 43, FIN-00014 University of Helsinki (Finland); Helsinki Institute of Physics, P.O. Box 43, FIN-00014 University of Helsinki (Finland); Levo, E.; Nordlund, K. [Department of Physics, P.O. Box 43, FIN-00014 University of Helsinki (Finland)


    Highlights: • We studied the damage buildup in equiatomic multicomponent alloys by MD simulations. • Edge dislocation mobility was lower in the studied alloys compared to elemental Ni. • Damage buildup in alloys saturated at lower levels than in elemental Ni. • Initial damage buildup is faster in alloys compared to elemental Ni. - Abstract: A new class of single phase metal alloys of equal atomic concentrations has shown very promising mechanical properties and good corrosion resistance. Moreover, a significant reduction in damage accumulation during prolonged irradiation has also been observed in these equiatomic multicomponent alloys. A comparison of elemental Ni with the two component NiFe- and the three component NiCoCr-alloy showed a substantial reduction in damage in both alloys, and an even larger difference was seen if only larger clusters were considered. One of the factors limiting the damage build-up in the alloys compared to the elemental material was seen to be dislocation mobility (Granberg et al., 2016). In this Article, we focus on a more thorough investigation of the mobility of edge dislocations in different cases of the Ni-, NiFe- and NiCoCr-samples. We find that even though the saturated amount of defects in the alloys is lower than in elemental Ni, the defect buildup in the early stages is faster in the alloys. We also find that the dislocation mobility in NiFe is lower than in Ni, at low stresses, and that the onset stress in NiFe is higher than in Ni. The same phenomenon was seen in comparison between NiFe and NiCoCr, since the three component alloy had lower dislocation mobility and higher onset stress. The dislocation velocity in elemental Ni plateaued out just under the forbidden velocity, whereas the alloys showed a more complex behaviour.


    Energy Technology Data Exchange (ETDEWEB)

    Alexandreanu, Bogdan; Chen, Yiren; Natesan, Ken; Shack, William J.


    The objective of this work was to obtain SCC growth data in Alloy 152 weld butter near the interface with Low Alloy Steel (LAS), which is a region where some dilution of Cr was expected to have occurred, thus presumably exhibiting an increased SCC-susceptibility vs. the bulk of the weld. The LAS piece used in this application was Alloy 533-Gr B from the Midland reactor lower head, and the Alloy 152 weld butter received a prototypical Post Weld Heat Treatment (PWHT) prior to joining by Alloy 152 to an Alloy 690 piece according to a procedure qualified to ASME IX. The compact tension specimens for SCC testing were aligned in the first layer of the Alloy 152 butter. The experimental approach based on tracking environmental enhancement vs. location was successful in identifying SCC-susceptible locations, and SCC rates ranging from 10-12 m/s to as high as 10-10 m/s were measured. The post-test examination of the specimens found that the fracture had the intergranular/interdendritic appearance typical of welds, and that the propagation was arrested wherever an intersection with the LAS occurred. The large range of SCC rates measured does not appear to correlate well with the local concentration of Cr (approx. 25% at the SCC locations), and, in fact, low Cr (20%) – high Fe “streaks” seemed to slow/arrest crack propagation. In short, simple “Cr dilution” does not seem to fully account for the “SCC-susceptible” microstructure that yielded the 10-10 m/s growth rate in this weld.

  4. Solid State Joining of Dissimilar Titanium Alloys (United States)

    Morton, Todd W.

    Solid state joining of titanium via friction stir welding and diffusion bonding have emerged as enablers of efficient monolithic structural designs by the eliminations fasteners for the aerospace industry. As design complexity and service demands increase, the need for joints of dissimilar alloys has emerged. Complex thermomechanical conditions in friction stir weld joints and high temperature deformation behavior differences between alloys used in dissimilar joints gives rise to a highly variable flow pattern within a stir zone. Experiments performed welding Ti-6Al-4V to beta21S show that mechanical intermixing of the two alloys is the primary mechanism for the generation of the localized chemistry and microstructure, the magnitude of which can be directly related to pin rotation and travel speed weld parameters. Mechanical mixing of the two alloys is heavily influenced by strain rate softening phenomena, and can be used to manipulate weld nugget structure by switching which alloy is subjected to the advancing side of the pin. Turbulent mixing of a weld nugget and a significant reduction in defects and weld forces are observed when the beta21S is put on the advancing side of the weld where higher strain rates are present. Chemical diffusion driven by the heat of weld parameters is characterized using energy dispersive x-ray spectroscopy (EDS) and is shown to be a secondary process responsible for generating short-range chemical gradients that lead to a gradient of alpha particle structures. Diffusion calculations are inconsistent with an assumption of steady-state diffusion and show that material interfaces in the weld nugget evolve through the break-down of turbulent interface features generated by material flows. A high degree of recrystallization is seen throughout the welds, with unique, hybrid chemistry grains that are generated at material interfaces in the weld nugget that help to unify the crystal structure of dissimilar alloys. The degree of

  5. Fabrication and characterization of Ti-Nb-HA alloy by mechanical alloying and spark plasma sintering for hard tissue replacements (United States)

    Singh, Ramandeep; Pal Singh, Bhupinder; Gupta, Anjali; Prakash, Chander


    In the present research work, a β-type Ti-35Nb-10HA alloy was successfully fabricated by mechanical alloying of titanium (Ti), niobium (Nb), and hydroxyaptite (HA) powders followed by consolidation using Spark Plasma Sintering technique. The effect of HA on the microstructure and mechanical properties were studied. The microstructure, surface topography, and element composition of the Ti-Nb-HA alloy was investigated using optical microscope, field-emission scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The micro-hardness of the specimens was measured on a Vickers hardness tester. The microstructure examination of the compact revealed that the alloy distinctly shows the primary grain boundaries along with secondary grain boundary. It was observed that complex reactions between HA and alloy elements occurred during the sintering process of Ti-35Nb-10HA alloy and biocompatible phases [Ca3(PO4)2, CaTiO3, Nb8P5, CaO, TiP, Nb4O5, and TiO2] were generated in the compact, which is beneficial to form apatite and improved the bioactivity of the alloy for osseiointegartion. The fabricated Ti-35Nb-15HA alloy exhibits maximum micro-hardness (∼786 HV), which is very high value as compared to the alloys reported in literature. Based on these above observations, it is expected that the as-fabricated Ti-35Nb-10HA alloy is suggested for dental and orthopaedic applications.

  6. Improving tribological properties of Ti-5Zr-3Sn-5Mo-15Nb alloy by double glow plasma surface alloying

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Lili; Qin, Lin, E-mail:; Kong, Fanyou; Yi, Hong; Tang, Bin


    Highlights: • The Mo alloyed layers were successfully prepared on TLM surface by DG-PSA. • The surface microhardness of TLM is remarkably enhanced by Mo alloying. • The TLM samples after Mo alloying exhibit good wettability. • The Mo alloyed TLM samples show excellent tribological properties. - Abstract: Molybdenum, an alloying element, was deposited and diffused on Ti-5Zr-3Sn-5Mo-15Nb (TLM) substrate by double glow plasma surface alloying technology at 900, 950 and 1000 °C. The microstructure, composition distribution and micro-hardness of the Mo modified layers were analyzed. Contact angles on deionized water and wear behaviors of the samples against corundum balls in simulated human body fluids were investigated. Results show that the surface microhardness is significantly enhanced after alloying and increases with treated temperature rising, and the contact angles are lowered to some extent. More importantly, compared to as-received TLM alloy, the Mo modified samples, especially the one treated at 1000 °C, exhibit the significant improvement of tribological properties in reciprocating wear tests, with lower specific wear rate and friction coefficient. To conclude, Mo alloying treatment is an effective approach to obtain excellent comprehensive properties including optimal wear resistance and improved wettability, which ensure the lasting and safety application for titanium alloys as the biomedical implants.

  7. Noble metal alloys for metal-ceramic restorations. (United States)

    Anusavice, K J


    A review of the comparative characteristics and properties of noble metal alloys used for metal-ceramic restorations has been presented. Selection of an alloy for one's practice should be based on long-term clinical data, physical properties, esthetic potential, and laboratory data on metal-ceramic bond strength and thermal compatibility with commercial dental porcelains. Although gold-based alloys, such as the Au-Pt-Pd, Au-Pd-Ag, and Au-Pd classes, may appear to be costly compared with the palladium-based alloys, they have clearly established their clinical integrity and acceptability over an extended period of time. Other than the relatively low sag resistance of the high gold-low silver content alloys and the potential thermal incompatibility with some commercial porcelain products, few clinical failures have been observed. The palladium-based alloys are less costly than the gold-based alloys. Palladium-silver alloys require extra precautions to minimize porcelain discoloration. Palladium-copper and palladium-cobalt alloys may also cause porcelain discoloration, as copper and cobalt are used as colorants in glasses. The palladium-cobalt alloys are least susceptible to high-temperature creep compared with all classes of noble metals. Nevertheless, insufficient clinical data exist to advocate the general use of the palladium-copper and palladium-cobalt alloys at the present time. One should base the selection and use of these alloys in part on their ability to meet the requirements of the ADA Acceptance Program. A list of acceptable or provisionally acceptable alloys is available from the American Dental Association and is published annually in the Journal of the American Dental Association. Dentists have the legal and ethical responsibility for selection of alloys used for cast restorations. This responsibility should not be delegated to the dental laboratory technician. It is advisable to discuss the criteria for selection of an alloy with the technician and the

  8. Effects of alloying elements and temperature on the elastic properties of W-based alloys by first-principles calculations

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Yong-Jie, E-mail: [Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA 16802 (United States); Shang, Shun-Li; Wang, Yi [Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA 16802 (United States); Darling, Kristopher A.; Butler, Brady G.; Kecskes, Laszlo J. [U.S. Army Research Laboratory, Weapons and Materials Research Directorate, RDRL-WMM-F, Aberdeen Proving Ground, MD 21005 (United States); Liu, Zi-Kui [Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA 16802 (United States)


    The influence of various transition alloying elements (X's) on the elastic properties of W-based alloys has been studied via first-principles calculations on the basis of density functional theory. Here, nineteen transition metal alloying elements (X) are considered: Ti, V, Cr, Fe, Co, Ni, Y, Zr, Nb, Mo, Ru, Rh, Pd, Hf, Ta, Re, Os, Ir, and Pt. It is found that (i) the bulk modulus of the dilute W-X alloy decreases with increasing its equilibrium volume, particularly, for the alloying elements in the same period; (ii) all of the alloying elements decrease the shear modulus of BCC W; and (iii) the largest decrease of elastic properties of W is due to alloying element Y. In addition, it is shown that the changes of elastic properties of W caused by the alloying elements are traceable from the electron charge density distribution, resulting in a bonding distortion between W and the alloying atoms. Using the quasi-static approach based on the Debye model, the elastic properties of these W-X alloys at finite temperatures are predicted. Calculated properties of BCC W and the W-X alloys are in favorable agreement with available experimental measurements. - Highlights: • The effects of nineteen metal elements on the elastic properties of W are studied. • The elastic properties at finite temperatures are predicted by the Debye model. • The alloying effects can be traceable from the changes of electronic structure. • The possibly promising alloying elements to soften BCC W are suggested.

  9. [Cracking in laser welds of dental Ni-Cr alloys. Effect of alloy composition]. (United States)

    Matsui, Y


    For the purpose of clarifying the effect of alloy compositions on cracking in laser welds of dental Ni-Cr alloys, 12 commercial and 11 experimental Ni-Cr alloys for crown and bridges were subjected to pulsed YAG laser spot welding, and their welds were investigated by optical and scanning electron microscopy, and EDX and thermal analysis methods. Main conclusions are as follows. 1. Cracks in laser welds were solidification cracks at grain boundaries in weld fusion zones. 2. In the case of commercial dental Ni-Cr alloys, a considerable number of eutectics enriched in Si, A1 and/or S were formed. Greater cracking susceptibility was interpreted by considering that these eutectics solidified at solidification temperatures far lower than the nominal solidus. 3. In the case of experimental Ni-Cr alloys with a small amount of eutectics, S and Si enhanced cracking sensitivity, but Mn reduced cracking. 4. The above results suggest that it is beneficial to the prevention or reduction of cracking to decrease harmful elements such as Si and S forming low solidification temperature eutectics or to add some elements such as Mn forming higher solidification temperature eutectics instead of lower ones.

  10. Characterization of Dispersion Strengthened Copper Alloy Prepared by Internal Oxidation Combined with Mechanical Alloying (United States)

    Zhao, Ziqian; Xiao, Zhu; Li, Zhou; Zhu, Mengnan; Yang, Ziqi


    Cu-3.6 vol.% Al2O3 dispersion strengthened alloy was prepared by mechanical alloying (MA) of internal oxidation Cu-Al powders. The lattice parameter of Cu matrix decreased with milling time for powders milled in argon, while the abnormal increase of lattice parameter occurred in the air resulting from mechanochemical reactions. With a quantitative analysis, the combined method makes residual aluminum oxidized completely within 10-20 h while mechanical alloying method alone needs longer than 40 h. Lamellar structure formed and the thickness of lamellar structure decreased with milling time. The size of Al2O3 particles decreased from 46 to 22 nm after 40 h milling. After reduction, core-shell structure was found in MAed powders milled in the air. The compacted alloy produced by MAed powders milled in the argon had an average hardness and electrical conductivity of 172.2 HV and 82.1% IACS while the unmilled alloy's were 119.8 HV and 74.1% IACS due to the Al2O3 particles refinement and residual aluminum in situ oxidization.

  11. Refinement and fracture mechanisms of as-cast QT700-6 alloy by alloying method

    Directory of Open Access Journals (Sweden)

    Min-qiang Gao


    Full Text Available The as-cast QT700-6 alloy was synthesized with addition of a certain amount of copper, nickel, niobium and stannum elements by alloying method in a medium frequency induction furnace, aiming at improving its strength and toughness. Microstructures of the as-cast QT700-6 alloy were observed using a scanning-electron microscope (SEM and the mechanical properties were investigated using a universal tensile test machine. Results indicate that the ratio of pearlite/ferrite is about 9:1 and the graphite size is less than 40 μm in diameter in the as-cast QT700-6 alloy. The predominant refinement mechanism is attributed to the formation of niobium carbides, which increases the heterogeneous nucleus and hinders the growth of graphite. Meanwhile, niobium carbides also exist around the grain boundaries, which improve the strength of the ductile iron. The tensile strength and elongation of the as-cast QT700-6 alloy reach over 700 MPa and 6%, respectively, when the addition amount of niobium is 0.8%. The addition of copper and nickel elements contributed to the decrease of eutectoid transformation temperature, resulting in the decrease of pearlite lamellar spacing (about 248 nm, which is also beneficial to enhancing the tensile strength. The main fracture mechanism is cleavage fracture with the appearance of a small amount of dimples.

  12. 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


    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......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...

  13. Development and Processing Improvement of Aerospace Aluminum Alloys (United States)

    Lisagor, W. Barry; Bales, Thomas T.


    This final report, in multiple presentation format, describes a comprehensive multi-tasked contract study to improve the overall property response of selected aerospace alloys, explore further a newly-developed and registered alloy, and correlate the processing, metallurgical structure, and subsequent properties achieved with particular emphasis on the crystallographic orientation texture developed. Modifications to plate processing, specifically hot rolling practices, were evaluated for Al-Li alloys 2195 and 2297, for the recently registered Al-Cu-Ag alloy, 2139, and for the Al-Zn-Mg-Cu alloy, 7050. For all of the alloys evaluated, the processing modifications resulted in significant improvements in mechanical properties. Analyses also resulted in an enhanced understanding of the correlation of processing, crystallographic texture, and mechanical properties.

  14. Tribological research of cobalt alloys used as biomaterials

    Directory of Open Access Journals (Sweden)

    Robert Karpiński


    Full Text Available This study provides information about the cobalt alloys used in dentistry and medicine. The work includes a review of the literature describing the general properties of cobalt alloys. In addition it describes the impact of the manufacturing conditions and alloy additives used , on the structure and mechanical properties of these alloys. The research methodology and the results obtained has been presented in the study. Two cobalt-based alloys Co-CrMo-W and Co-Cr-Ni-Mo were selected for the tests. The first one was prepared with the use of casting technique whereas the second was obtained due to plastic forming. An analysis of the chemical composition and in vitro tribological tests with the use of tribotester of "ball-on-disc" type was conducted. Comparative tribological characteristics of these alloys has been presented.

  15. Production of FR Tubing from Advanced ODS Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Maloy, Stuart Andrew [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Lavender, Curt [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Omberg, Ron [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Lewandowski, John [Case Western Reserve Univ., Cleveland, OH (United States)


    Significant research is underway to develop LWR nuclear fuels with improved accident tolerance. One of the leading candidate materials for cladding are the FeCrAl alloys. New alloys produced at ORNL called Gen I and Gen II FeCrAl alloys possess excellent oxidation resistance in steam up to 1400°C and in parallel methods are being developed to produce tubing from these alloys. Century tubing continues to produce excellent tubing from FeCrAl alloys. This memo reports receipt of ~21 feet of Gen I FeCrAl alloy tubing. This tubing will be used for future tests including burst testing, mechanical testing and irradiation testing.

  16. Cast iron-base alloy for cylinder/regenerator housing (United States)

    Witter, Stewart L.; Simmons, Harold E.; Woulds, Michael J.


    NASACC-1 is a castable iron-base alloy designed to replace the costly and strategic cobalt-base X-40 alloy used in the automotive Stirling engine cylinder/generator housing. Over 40 alloy compositions were evaluated using investment cast test bars for stress-rupture testing. Also, hydrogen compatibility and oxygen corrosion resistance tests were used to determine the optimal alloy. NASACC-1 alloy was characterized using elevated and room temperature tensile, creep-rupture, low cycle fatigue, heat capacity, specific heat, and thermal expansion testing. Furthermore, phase analysis was performed on samples with several heat treated conditions. The properties are very encouraging. NASACC-1 alloy shows stress-rupture and low cycle fatigue properties equivalent to X-40. The oxidation resistance surpassed the program goal while maintaining acceptable resistance to hydrogen exposure. The welding, brazing, and casting characteristics are excellent. Finally, the cost of NASACC-1 is significantly lower than that of X-40.

  17. Rapidly solidified Mg-Al-Zn-rare earth alloys

    Energy Technology Data Exchange (ETDEWEB)

    Chang, C.F.; Das, S.K.; Raybould, D.


    Among the light metal alloys, magnesium is the lightest structural material except for beryllium, and yet magnesium alloys have not seen extensive use because of their poor strength and corrosion resistance. Rapid solidification technology offers a possible solution to these problems. A number of Mg-Al-Zn alloys containing rare earth (RE) elements (e.g. Ce, Pr, Y, and Nd) have been investigated using rapid solidification processing for possible structural applications. The processing consists of planar flow or jet casting into ribbons, pulverization of ribbon to powder, and consolidation of powder into bulk shapes. The mechanical properties of some of these alloys show attractive combinations of strength, ductility and corrosion resistance. The microstructures of these alloys are correlated with their mechanical properties. The rapidly solidified Mg-Al-Zn-RE alloys show great potential for applications in automotive and aerospace industries. 7 references.

  18. Cryogenic properties of a new tough-strong iron alloy (United States)

    Stephens, J. R.; Witzke, W. R.


    A program was undertaken to develop an iron-base alloy having a fracture toughness of 220 MPa-sq root meters with a corresponding yield stress of 1.4 GPa (200 ksi) at -196 C. An Fe-12Ni alloy was selected as the base alloy. Factors considered include reactive metal additions, effects of interstitial impurities, strengthening mechanisms, and weldability. The goals of this program were met in an Fe-12Ni-0.5Al alloy strengthened by thermomechanical processing or by precipitate strengthening with 2 percent Cu. The alloy is weldable with the weld metal and heat affected zone in the post-weld annealed condition having toughness equivalent to the base alloy.

  19. Shape memory alloys: New materials for future engineering (United States)

    Hornbogen, E.


    Shape memory is a new material property. An alloy which experiences relative severe plastic deformation resumes its original shape again after heating by 10 to 100 C. Besides simple shape memory, in similar alloys there is the second effect where the change in shape is caused exclusively by little temperature change. In pseudo-elasticity, the alloy exhibits a rubber-like behavior, i.e., large, reversible deformation at little change in tension. Beta Cu and beta NiTi alloys have been used in practice. The probability is that soon alloys based on Fe will become available. Recently increasing applications for this alloy were found in various areas of technology, even medical technology. A review with 24 references is given, including properties, production, applications and fundamental principles of the shape memory effect.

  20. Mechanical alloying in the Fe-Cu system

    DEFF Research Database (Denmark)

    Jiang, Jianzhong; Gente, C.; Bormann, R.


    The studies of mechanical alloying on the Fe-Cu system, as a model system for those with positive heats of mixing, are reviewed. Several problems involved in the mechanical alloying process are discussed. For example, (1) whether alloying occurs on an atomic level; (2) what the solid solubility...... in the Fe-Cu system is; (3) where the positive energy is stored in the alloys; (4) what the decomposition process of the supersaturated alloys is; and (5) what type of magnetic properties the new materials have. The elucidation of these problems will shed light on the understanding of the mechanisms...... for the preparation of materials under highly non-equilibrium conditions in systems with positive heats of mixing by mechanical alloying....

  1. Research activities of biomedical magnesium alloys in China (United States)

    Zheng, Yufeng; Gu, Xuenan


    The potential application of Mg alloys as bioabsorable/biodegradable implants have attracted much recent attention in China. Advances in the design and biocompatibility evaluation of bio-Mg alloys in China are reviewed in this paper. Bio-Mg alloys have been developed by alloying with the trace elements existing in human body, such as Mg-Ca, Mg-Zn and Mg-Si based systems. Additionally, novel structured Mg alloys such as porous, composited, nanocrystalline and bulk metallic glass alloys were tried. To control the biocorrosion rate of bio-Mg implant to match the self-healing/regeneration rate of the surrounding tissue in vivo, surface modification layers were coated with physical and chemical methods.


    Directory of Open Access Journals (Sweden)

    V. K. Afanasiev


    Full Text Available A new approach to the preparation of aluminum-silicon alloys, based on the concept of the leading role of hydrogen in determining the structure and properties of alloys consists in using as charge materials of silicon dioxide (silica and hydrogen instead of crystalline silicon was described. Practical ways to implement the new method were proposed on the example of industrial alloys prepared on charge synthetic alloy. It is shown that the application of the proposed method allows to improve the mechanical properties and reduce the coefficient of thermal expansion alloys, Al-Si. The effect of heat treatment on mechanical properties, density and thermal expansion of synthetic alloys was researched.

  3. Bonding of Aluminum Alloys in Compound Casting (United States)

    Feng, Jian; Ye, Bing; Zuo, Lijie; Wang, Qudong; Wang, Qigui; Jiang, Haiyan; Ding, Wenjiang


    The influence of the coating materials, coating thickness, and casting process on the interfacial microstructure and mechanical properties of the overcast A6061 bars with aluminum A356 and A6061 alloys was studied by OM, SEM/EDS, and mechanical testing. Results indicate that Ni coating has better thermal stability than Cu coating that heavily reacts with liquid Al alloy and forms a reaction zone around 130-150 μm during gravity casting. In the gravity casting, coarse and cracked Al3Ni phase distributes along the interfacial region and degrades the mechanical properties of the overcast joints. In squeeze casting, however, fine and dispersed Ni-rich strengthening phases form uniformly in the interfacial zone and improve the metallurgical bonding of the joints. The heat transition and application of pressure during solidification are two key factors in determining the integrity and mechanical properties of the overcast joints.

  4. Corrosion fatigue of magnesium alloys in oil

    Energy Technology Data Exchange (ETDEWEB)

    Eliezer, A.; Haddad, J. [Sami Shamoon College of Engineering, Corrosion Research Center, P.O.B. 45, Beer-Sheva 84100 (Israel); Medlinsky, O. [N.Z.M-Israel Chevron Texaco Agency (Israel)


    Today we are facing an era which demands us to think about the future of our planet. On one hand we need to stabilize the earth resources. On the other hand we need to continue to develop the transportation use by aircraft, ships, cars and trains. In order to accomplish this mission we must consider the use of light materials. Saving fuel consumption is becoming more important due to concern for the global environment and the need for resource and energy conservation. Therefore the investigation of the light materials, such as the magnesium, and their environmental behavior is very important. One of the most commented environments in the automobile industrial, and in any industrial, is oil. Oil is used almost in every metal moving part. Therefore, the investigation of oil influence on the metal is crucial. The automobile burning engine increases the temperature of all the attached components to about 90 deg. C. This high temperature must be considered if we want to investigate the real condition which the magnesium alloy is facing. In order to use magnesium alloys in the automotive industry for items such as wheels, gearbox housing and more, the fatigue phenomenon must be investigated. Understanding this phenomenon will increase the magnesium consumption, In addition, the environmental influence in formation is a main factor of the specimen fatigue life. Until now the fatigue phenomenon and the corrosion problems of magnesium alloys received separate treatment. However, in true active conditions, mechanicals and corrosive process are working together. The combination between the attack of environment, high temperature and dynamic cycle stress has been named corrosion fatigue. The result of these processes we can ascertained from the stress corrosion cracking. Today the most commercial magnesium alloy in die casting industry is AZ91D [9% Aluminum,1% Zinc] which has an excellent mechanicals property. Another magnesium alloy is AM50 [5% Aluminum, 0.3% Manganese] which

  5. Laser Brazing of High Temperature Braze Alloy (United States)

    Gao, Y. P.; Seaman, R. F.; McQuillan, T. J.; Martiens, R. F.


    The Space Shuttle Main Engine (SSME) consists of 1080 conical tubes, which are furnace brazed themselves, manifolds, and surrounding structural jacket making almost four miles of braze joints. Subsequent furnace braze cycles are performed due to localized braze voids between the coolant tubes. SSME nozzle experiences extremely high heat flux (180 mW/sq m) during hot fire. Braze voids between coolant tubes may result in hot combustion gas escape causing jacket bulges. The nozzle can be disqualified for flight or result in mission failure if the braze voids exceed the limits. Localized braze processes were considered to eliminate braze voids, however, damage to the parent materials often prohibited use of such process. Being the only manned flight reusable rocket engine, it has stringent requirement on the braze process. Poor braze quality or damage to the parent materials limits the nozzle service life. The objective of this study was to develop a laser brazing process to provide quality, localized braze joints without adverse affect on the parent materials. Gold (Au-Cu-Ni-Pd-Mn) based high temperature braze alloys were used in both powder and wire form. Thin section iron base superalloy A286 tube was used as substrate materials. Different Laser Systems including CO2 (10.6 micrometers, 1kW), ND:YAG (1.06 micrometers, 4kW). and direct diode laser (808nm. 150W) were investigated for brazing process. The laser process variables including wavelength. laser power, travel speed and angle of inclination were optimized according to bead geometry and braze alloy wetting at minimum heat input level, The properties of laser brazing were compared to that of furnace brazing. Microhardness profiles were used for braze joint property comparison between laser and furnace brazing. The cooling rate of laser brazing was compared to furnace brazing based on secondary dendritic arm spacing, Both optical and Scanning Electron Microscope (SEM) were used to evaluate the microstructures of

  6. Radiation resistant austenitic stainless steel alloys (United States)

    Maziasz, P.J.; Braski, D.N.; Rowcliffe, A.F.


    An austenitic stainless steel alloy, with improved resistance to radiation-induced swelling and helium embrittlement, and improved resistance to thermal creep at high temperatures, consisting essentially of, by weight percent: from 16 to 18% nickel; from 13 to 17% chromium; from 2 to 3% molybdenum; from 1.5 to 2.5% manganese; from 0.01 to 0.5% silicon; from 0.2 to 0.4% titanium; from 0.1 to 0.2% niobium; from 0.1 to 0.6% vanadium; from 0.06 to 0.12% carbon; from 0.01 to 0.03% nitrogen; from 0.03 to 0.08% phosphorus; from 0.005 to 0.01% boron; and the balance iron, and wherein the alloy may be thermomechanically treated to enhance physical and mechanical properties. 4 figs.

  7. Coating compositions comprising bismuth-alloyed zinc

    DEFF Research Database (Denmark)


    The present application discloses (i) a coating composition comprising a particulate zinc-based alloyed material, said material comprising 0.05-0.7% by weight of bismuth (Bi), the D50 of the particulate material being in the range of 2.5-30 µm; (ii) a coated structure comprising a metal structure...... having a first coating of the zinc-containing coating composition applied onto at least a part of the metal structure in a dry film thickness of 5-100 µm; and an outer coating applied onto said zinc-containing coating in a dry film thickness of 30-200 µm; (iii) a particulate zinc-based alloyed material...

  8. Benign joining of ultrafine grained aerospace aluminum alloys using nanotechnology. (United States)

    Longtin, Rémi; Hack, Erwin; Neuenschwander, Jürg; Janczak-Rusch, Jolanta


    Ultrafine grained aluminum alloys have restricted applicability due to their limited thermal stability. Metalized 7475 alloys can be soldered and brazed at room temperature using nanotechnology. Reactive foils are used to release heat for milliseconds directly at the interface between two components leading to a metallurgical joint without significantly heating the bulk alloy, thus preserving its mechanical properties. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Electric pulse treatment of welded joint of aluminum alloy


    A.A. Mitiaev; I. P. Volchok; Yu. L. Nadezhdin; V.A. Sokirko; I. A. Vakulenko


    Purpose. Explanation of the redistribution effect of residual strengthes after electric pulse treatment of arc welding seam of the aluminum alloy. Methodology. Alloy on the basis of aluminium of АК8М3 type served as the research material. As a result of mechanical treatment of the ingots after alloy crystallization the plates with 10 mm thickness were obtained. After edge preparation the elements, which are being connected were butt welded using the technology of semiautomatic argon arc weldi...

  10. Multi-functional magnesium alloys containing interstitial oxygen atoms


    H. Kang; Choi, H. J.; Kang, S W; Shin, S. E.; G. S. Choi; D. H. Bae


    A new class of magnesium alloys has been developed by dissolving large amounts of oxygen atoms into a magnesium lattice (Mg-O alloys). The oxygen atoms are supplied by decomposing titanium dioxide nanoparticles in a magnesium melt at 720??C; the titanium is then completely separated out from the magnesium melt after solidification. The dissolved oxygen atoms are located at the octahedral sites of magnesium, which expand the magnesium lattice. These alloys possess ionic and metallic bonding ch...


    Directory of Open Access Journals (Sweden)

    V. Yu. Stetsenko


    Full Text Available It is shown that extent of modifying of an alloy is proportional to overcooling at its hardening, viscosity of fusion and interphase superficial energy of crystals of the leading phase. The key technological parameters of modifying of an alloy are the speed of its hardening, viscosity of fusion and extent of refinement from surface-active elements. Their adsorption on crystals of the leading phase interferes with modifying of an alloy.

  12. Fe-based magnetic shape memory alloy-sheet specimen (United States)

    Kanada, Tsugunori; Enokizono, Masato


    We contrived a new composite functional alloy which is compatible for both magnetization and the shape memory effect (SME). A FeMnSiCr alloy, one of the shape memory alloys (SMA) has strong magnetization in addition to SME after heating in air. It is because the specimen is composed of a ferromagnetic iron oxide Fe 3O 4 (magnetite) surface layer, the inside being SMA. The measurements were carried out on a sheet specimen.

  13. Effect of whitening toothpaste on titanium and titanium alloy surfaces


    Adriana Cláudia Lapria Faria; Angelo Rafael de Vito Bordin; Vinícius Pedrazzi; Renata Cristina Silveira Rodrigues; Ricardo Faria Ribeiro


    Dental implants have increased the use of titanium and titanium alloys in prosthetic applications. Whitening toothpastes with peroxides are available for patients with high aesthetic requirements, but the effect of whitening toothpastes on titanium surfaces is not yet known, although titanium is prone to fluoride ion attack. Thus, the aim of the present study was to compare Ti-5Ta alloy to cp Ti after toothbrushing with whitening and conventional toothpastes. Ti-5Ta (%wt) alloy was melted in ...

  14. Magnetic Properties of Amorphous Fe-Zr-B Alloys


    Shigehiro, Ohnuma; Masateru, Nose; Kiwamu, Shirakawa; Tsuyoshi, Masumoto; The Research Institute of Electric and Magnetic Alloys; Sumitomo Special Metal Co. Ltd.; The Research Institute of Electric and Magnetic Alloys; The Research Institute for Iron, Steel and Other Metals


    The formation range, magnetic properties and thermal stability for Fe-Zr-B amorphous alloys have been examined. The combination of zirconium and boron as glass formation elements is extremely effective both in expanding the formation range and increasing stability against crystallization for Fe-based amorphous alloys. Both the Curie temperature and saturation magnetization at room temperature decrease with increasing Zr content. Magnetostriction for the present alloys is smaller than that of ...

  15. Microstructure Development and Characteristics of Semisolid Aluminum Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Merton Flemings; srinath Viswanathan


    A drop forge viscometer was employed to investigate the flow behavior under very rapid compression rates of A357, A356 diluted with pure aluminum and Al-4.5%Cu alloys. The A357 alloys were of commercial origin (MHD and SIMA) and the rheocast, modified A356 and Al-4.5Cu alloys were produced by a process developed at the solidification laboratory of MIT.

  16. Characterization and Performance of Laser Alloyed Commercial Tool Steels

    Directory of Open Access Journals (Sweden)

    Miroslaw Sebastian Bonek


    Full Text Available 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. Selection of laser operating conditions is discussed, as well as alloying material, and their influence on structure and chemical composition of the steel. Analysis of the process conditions influence on thicknesses of the alloyed layer and heat-affected zone is presented.

  17. Cobalt alloy ion sources for focused ion beam implantation

    Energy Technology Data Exchange (ETDEWEB)

    Muehle, R.; Doebeli, M. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Zimmermann, P. [Eidgenoessische Technische Hochschule, Zurich (Switzerland)


    Cobalt alloy ion sources have been developed for silicide formation by focused ion beam implantation. Four eutectic alloys AuCo, CoGe, CoY and AuCoGe were produced by electron beam welding. The AuCo liquid alloy ion source was investigated in detail. We have measured the emission current stability, the current-voltage characteristics, and the mass spectrum as a function of the mission current. (author) 1 fig., 2 refs.

  18. Biaxial Testing of 2195 Aluminum Lithium Alloy Using Cruciform Specimens (United States)

    Johnston, W. M.; Pollock, W. D.; Dawicke, D. S.; Wagner, John A. (Technical Monitor)


    A cruciform biaxial test specimen was used to test the effect of biaxial load on the yield of aluminum-lithium alloy 2195. Fifteen cruciform specimens were tested from 2 thicknesses of 2195-T8 plate, 0.45 in. and 1.75 in. These results were compared to the results from uniaxial tensile tests of the same alloy, and cruciform biaxial tests of aluminum alloy 2219-T87.


    Saller, H.A.


    A process is presented for producing a workable article of a uranium- aluminum alloy in which the uranium content is between 14 and 70% by weight; aluminum powder and powdered UAl/sub 2/, UAl/sub 3/, UAl/sub 5/, or UBe/sub 9/ are mixed, and the mixture is compressed into the shape desired and sintered at between 450 and 600 deg C.

  20. Machining of low percentage beryllium copper alloys (United States)

    Habermeyer, J. G.


    Airborne beryllium sampling during machining of low percentage beryllium-copper alloys shows that normal dry machining creates 45.2 microgram/cu m of airborne beryllium in the casting operators breathing zone and 2.3 microgram/cu m in an adjacent machine working area. A small vacuum system placed over the tool effectively removes airborne beryllium in the breathing zone sample to 0.2 microgram/cu m.

  1. Fatigue damage monitoring of structural aluminum alloys

    Directory of Open Access Journals (Sweden)

    С.Р. Ігнатович


    Full Text Available  Results of the experiments directed on creation of a new tool method of fatigue damage diagnostics and an estimation of a residual life of aviation designs are presented. It is shown, that the defo rmation relief formed on a surface of cladding  layer of sheets of constructional alloys Д-16АТ, 2024-Т3, 7075-Т6  can be considered as the metal damage indicator  under cyclically repeating loadings.

  2. Hyperfine magnetic fields in substituted Finemet alloys

    Energy Technology Data Exchange (ETDEWEB)

    Brzózka, K., E-mail: [University of Technology and Humanities in Radom, Department of Physics (Poland); Sovák, P. [P.J. Šafárik University, Institute of Physics (Slovakia); Szumiata, T.; Gawroński, M.; Górka, B. [University of Technology and Humanities in Radom, Department of Physics (Poland)


    Transmission Mössbauer spectroscopy was used to determine the hyperfine fields of Finemet-type alloys in form of ribbons, substituted alternatively by Mn, Ni, Co, Al, Zn, V or Ge of various concentration. The comparative analysis of magnetic hyperfine fields was carried out which enabled to understand the role of added elements in as-quenched as well as annealed samples. Moreover, the influence of the substitution on the mean direction of the local hyperfine magnetic field was examined.

  3. Investigation into the grinding of titanium alloys


    Wang, S. H.


    Titanium alloys are used extensively in the aerospace industry due to their high specific strength and excellent corrosion resistance. However, their poor thermal conductivity and high chemical reactivity with tool materials make the machining difficult, especially when grinding. During grinding, the excessive heat generated at the wheel-work piece interface may result in poor surface finisil,1_, a transformed surface layer, excessive plastic deformation, thermallyinduced...

  4. Mechanical properties of low tantalum alloys (United States)

    Kortovich, C. S.


    The mechanical property behavior of equiaxed cast B-1900 + Hf alloy as a function of tantalum content was studied. Tensile and stress rupture characterization was conducted on cast to size test bars containing tantalum at the 4.3% (standard level), 2.2% and 0% levels. Casting parameters were selected to duplicate conditions used to prepare test specimens for master metal heat qualification. The mechanical property results as well as results of microstructural/phase analysis of failed test bars are presented.

  5. Aluminum-Alloy-Matrix/Alumina-Reinforcement Composites (United States)

    Kashalikar, Uday; Rozenoyer, Boris


    Isotropic composites of aluminum-alloy matrices reinforced with particulate alumina have been developed as lightweight, high-specific-strength, less-expensive alternatives to nickel-base and ferrous superalloys. These composites feature a specific gravity of about 3.45 grams per cubic centimeter and specific strengths of about 200 MPa/(grams per cubic centimeter). The room-temperature tensile strength is 100 ksi (689 MPa) and stiffness is 30 Msi (206 GPa). At 500 F (260 C), these composites have shown 80 percent retention in strength and 95 percent retention in stiffness. These materials also have excellent fatigue tolerance and tribological properties. They can be fabricated in net (or nearly net) sizes and shapes to make housings, pistons, valves, and ducts in turbomachinery, and to make structural components of such diverse systems as diesel engines, automotive brake systems, and power-generation, mining, and oil-drilling equipment. Separately, incorporation of these metal matrix composites within aluminum gravity castings for localized reinforcement has been demonstrated. A composite part of this type can be fabricated in a pressure infiltration casting process. The process begins with the placement of a mold with alumina particulate preform of net or nearly net size and shape in a crucible in a vacuum furnace. A charge of the alloy is placed in the crucible with the preform. The interior of the furnace is evacuated, then the furnace heaters are turned on to heat the alloy above its liquidus temperature. Next, the interior of the furnace is filled with argon gas at a pressure about 900 psi (approximately equal to 6.2 MPa) to force the molten alloy to infiltrate the preform. Once infiltrated, the entire contents of the crucible can be allowed to cool in place, and the composite part recovered from the mold.

  6. Layered Structures in Deformed Metals and Alloys

    DEFF Research Database (Denmark)

    Hansen, Niels; Zhang, Xiaodan; Huang, Xiaoxu


    by the way of examples of different processing routes: friction, wire drawing, shot peening, high pressure torsion and rolling. The interlamellar spacing reaches from 5-10 nanometers to about one micrometer and the analysis will cover structural evolution, strengthening parameters and strength......-structure relationships. Finally, the results will be discussed based on universal principles for the evolution of microstructure and properties during plastic deformation of metals and alloys from low to high strain....

  7. Powder metallurgy of turbine disc alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ingesten, N.G. (Dep. of Engineering Metals)


    The first part embraced a study of carbide precipitated in IN 100 and astrology powders. The powder was heat treated at temperatures between 950/sup 0/C and 1150/sup 0/C. After aging at 950-1100/sup 0/C the MC-carbides formed during atomization were replaced by M/sub 23/C/sub 6/-carbides. After 1150/sup 0/C treatments the MC carbides were present again. Precipitation comparable with that obtained in HIP:ed specimens was not observed at free particle surfaces. However, powder particles which had agglomerated during atomization often exhibited considerable precipitation at contiguous surfaces. Obviously, contact between the particles must occur if coarse precipitation at particle surfaces is to develop. Reduced PPB-precipitation was obtained by pre-heat- treatment of powder before compaction. It is suggested that the carbon otherwise available for PPB-precipitation forms carbides in the interior of the powder particles. The aim of the second part was to ..gamma..-strengthen a Co-based super-alloy (Co-15Cr-3Mo-5Ti). Here the Ti-addition gives a coherent and ordered ..gamma..-phase Co/sub 3/Ti. However, upon ageing the alloy is unstable in order to increase the stability modifications of the alloy were prepared by: leaving out the Mo-content, adding 10 % Ni and by decreasing the Ti-content to 4.2 %. In addition, the effect of enhanced grain size and of deformation was investigated. Significant reduction of the transformation rate was only obtained by decresing the Ti-content while deformation of the alloy greatly increased the transformation rate.(author).

  8. Abrasive Wear Resistance of Overlay Composite Alloy with Addition of Carbide Powders


    Tadao, ARAKI; Minoru, NISHIDA; Akio, HIROSE; Kouji, YANO; HIroshi, FUJITA; Faculty of Eng., Ehime University; Faculty of Eng., Ehime University; Faculty of Eng., Osaka University; Kawasaki Steel Co., Ltd.; Tokuden Co., Ltd.


    The overall objective of this project is to provide data showing how carbide powder in addition to base alloy powder can be used effectively to increase hardness of overlay alloy and resistance to abrasive wear. An experimental study was performed to examine combinations of base alloy powders and reinforcing powders. The base alloy powders considered were stainless steel, Ni-base alloy, Co-base alloy and high speed steel powder, while reinforcing powders considered were metal-carbide and cera...

  9. Surface treatment of mercury-free alloys. (United States)

    Geiger, S B; Gurbatov, D; Dariel, M P; Eichmiller, F C; Liberman, R; Ratzker, M


    Finishing and polishing methods were examined for two metallic direct restorative materials being proposed as possible alternatives to amalgam, namely a gallium alloy and a consolidated silver alloy. The polished surfaces were compared to a conventional spherical amalgam (Tytin). After initial surface treatment with a 12-fluted tungsten carbide bur in a high-speed dental hand-piece, three polishing methods were evaluated: slow-speed polishing burs, rubber polishing points, and polishing disks (Sof-Lex). Each of these methods was followed by an additional surface treatment in which a pumice-flour/water slurry was applied with a rotary brush and a final surface treatment with a zinc-oxide/ethanol slurry that was applied with rotary rubber cups. The surface roughness was evaluated by profilometric measurements and light microscopy. The results showed that the smoothest surfaces for all metals were achieved with rotary finishing and polishing disks. Using the rubber points resulted in surfaces that were statistically similar to the disk-polished surfaces on all three materials. The polished surface of gallium alloy was consistently slightly rougher than that of amalgam. The consolidated silver also presented a consistently rougher surface than did amalgam, although these differences were not statistically significant. The additional polishing with pumice and zinc oxide improved the luster, but did not significantly improve the measured surface smoothness in any of the restorative materials studied.

  10. Aluminum alloy metallization for integrated circuits

    Energy Technology Data Exchange (ETDEWEB)

    Ghate, P.B.


    Aluminum metallization is most widely used for contacts and interconnections in both bipolar and MOS integrated circuits. Aluminum alloy films, such as Al-Si and Al-Cu films, were introduced to minimize the erosion of silicon from contact windows and to improve the electromigration resistance of interconnections. Recently, magnetron sputter-deposited aluminum, Al-2wt.%Cu and Al-2wt.%Cu-1wt.%Si films were employed to study the stability and contact resistance of Si-(Al alloy film) contacts on devices with shallow junction depths of the order of 0.35 Test structures were used to determine the leakage currents of 100n/sup +//p/sup +/ diodes as a function of the storage time (up to 1000 h) at 150 C, and the physical nature of the Si-(Al alloy) contacts was examined using scanning electron microscopy. The compatibility of the Al-Cu-Si metallization with the very large scale integrated requirements of interconnection and Si-metal contacts for shallow junction devices is discussed.

  11. Potential automotive uses of wrought magnesium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Gaines, L.; Cuenca, R.; Wu, S. [Argonne National Lab., IL (United States); Stodolsky, F. [Argonne National Lab., IL (United States)]|[Argonne National Lab., Washington, DC (United States)


    Vehicle weight reduction is one of the major means available to improve automotive fuel efficiency. High-strength steels, aluminum (Al), and polymers are already being used to reduce weight significantly, but substantial additional reductions could be achieved by greater use of low-density magnesium (Mg) and its alloys. Mg alloys are currently used in relatively small quantities for auto parts, generally limited to die castings (e.g., housings). Argonne National Laboratory`s Center for Transportation Research has performed a study for the Lightweight Materials Program within DOE`s Office of Transportation Materials to evaluate the suitability of wrought Mg and its alloys to replace steel/aluminum for automotive structural and sheet applications. Mg sheet could be used in body nonstructural and semi-structural applications, while extrusions could be used in such structural applications as spaceframes. This study identifies high cost as the major barrier to greatly increased Mg use in autos. Two technical R and D areas, novel reduction technology and better hot-forming technology, could enable major cost reductions.

  12. Studies on yttrium-containing smart alloys

    Energy Technology Data Exchange (ETDEWEB)

    Klein, Felix; Wegener, Tobias; Litnovsky, Andrey; Rasinski, Marcin; Linsmeier, Christian [Forschungszentrum Juelich GmbH, Institut fuer Energie- und Klimaforschung - Plasmaphysik (Germany); Mayer, Joachim [Ernst Ruska-Centrum, 52425 Juelich (Germany)


    Tungsten is the main candidate as plasma-facing armour material for future fusion reactors, like DEMO. Advantages of tungsten include high melting point, high thermal conductivity, low tritium retention, and low erosion yield. A problem is oxide volatilisation under accidental conditions where the temperature of the first wall can reach 1200 K to 1450 K and air ingress occurs. Therefore smart tungsten alloys are developed. Smart alloys are supposed to preserve properties of tungsten during plasma operation coupled with suppressed tungsten oxide formation in case of an accident. Lab-scale tungsten-chromium-yttrium (W-Cr-Y) samples prepared by magnetron sputtering are used as model system. The mechanisms of oxidation and its dynamics are studied using a thermogravimetric system, focussed ion beam, and electron microscopy. A composition scan was conducted: The new material composition featuring W, ∝ 12 wt.% Cr, ∝ 0.3 wt.% Y showed strongest suppression of oxidation, no pores, and least internal oxidation. At 1273 K in argon-oxygen atmosphere an oxidation rate of 3 . 10{sup -6} mg{sup 2}cm{sup -4}s{sup -1} was measured. At 1473 K ternary W-Cr-Y alloys suppressed evaporation up to 20 min while for W-Cr evaporation was already evident after 5 min. Comparison of passivation in dry and humid atmosphere, at temperatures of 1073 K to 1473 K is performed.

  13. Osseointegration of cobalt-chrome alloy implants. (United States)

    Mavrogenis, Andreas F; Papagelopoulos, Panayiotis J; Babis, George C


    Osseointegration or osteointegration refers to a direct bone-to-metal interface without interposition of non-bone tissue. The long-term clinical success of bone implants is critically related to wide bone-to-implant direct contact. However, only poor bone formation or even host bone resorption have been shown where bone is in tight contact with the implant surface. It has been suggested that an appropriate space between implant and host bone may be useful for early peri-implant bone formation. Additionally, osseointegration depends on the topographical and chemical characteristics of the implant surface. Cobalt-chrome (Co-Cr) is a metal alloy of cobalt and chromium. Because of its high strength, temperature endurance and wear resistance, it is commonly used in dental and orthopedic implants. In orthopedic implants it is usually composed of cobalt with chromium, molybdenum, and traces of other elements. Co-Cr alloys are especially useful where high stiffness or a highly polished and extremely wear-resistant material is required. This article reviews the Co-Cr alloy orthopedic implants in terms of their properties, porous coating, osseointegration, outcome, and failure.

  14. Optical response of noble metal alloy nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Bansal, Amit, E-mail:; Verma, S.S.


    The optical response, stability, and cost-effectiveness of individual noble metals can be improved by combining them to form alloy nanostructures. The present work reveals the influence of shape, size, and metal type on the optical response of alloy nanoparticles using discrete dipole approximation (DDA) simulations. It is found that sharp corner nanostructures show enhanced plasmonic properties in comparison to rounded counterpart. For all the three shapes, viz., nanocubes, rectangular, and nanobar particles, the increase in length resulted in redshifts of the longitudinal plasmon resonance alongwith enhancement in the scattering yield as well as relative efficiency parameters except for nanocubes of edge length 120 nm. The effect of size on full width at half maxima (FWHM) has also been studied and found to be maximal for nanocubes in comparison to other nanostructures. - Highlights: • The optical response of alloy nanostructures has been studied by discrete dipole approximation. • Sharp corner nanostructures show enhanced plasmonic properties. • Nanobars may be preferred over other nanostructures for absorption-based plasmonic applications. • Nanocubes of edge length greater than 100 nm may be useful for plasmonic solar cells. • Rectangular and nanobar particles may be preferred over nanocubes in plasmon sensing.

  15. Multimetallic alloy nanotubes with nanoporous framework. (United States)

    Choi, Bu-Seo; Lee, Young Wook; Kang, Shin Wook; Hong, Jong Wook; Kim, Jung; Park, Inkyu; Han, Sang Woo


    One-dimensional nanotubes (NTs) that consist of multiple metallic components are promising platforms for potential applications, whereas only a few synthetic methods of multimetallic NTs have been reported to date. In the present work, we developed a general synthesis route for the production of uniform multicomponent one-dimensional tubular nanostructures with various combinations of Pt, Pd, and Ag by using ZnO nanowires (NWs) as sacrificial templates. The ZnO NWs serve not only as physical templates but also as nucleation sites for the reduction of metal precursors, and thereby several metal precursors could be reduced simultaneously to produce multimetallic NTs. By using this approach, Pt-Pd, Pt-Ag, and Pd-Ag binary alloy NTs, and even Pt-Pd-Ag ternary alloy NTs could be successfully prepared. The prepared Pt-Pd binary alloy NTs exhibited improved electrocatalytic activity and stability toward ethanol oxidation due to their characteristic tubular morphology with well-interconnected nanoporous framework and synergism between two constituent metals. Furthermore, our approach can facilitate the fabrication of patterned multimetallic NT arrays on solid and flexible substrates with strong mechanical robustness. The present templating method does not require any extra steps to remove templates or additional surfactants which are often required to control the shape of nanostructures. This strategy offers a convenient, versatile, low-cost, and highly valuable approach to the fabrication of multimetallic nanostructures with various components and compositions.

  16. Laser weldability of Pt and Ti alloys

    Energy Technology Data Exchange (ETDEWEB)

    Noolu, N.J. [Center for Advanced Materials Joining, University of Waterloo, Waterloo (Canada)]. E-mail:; Kerr, H.W. [Center for Advanced Materials Joining, University of Waterloo, Waterloo (Canada); Zhou, Y. [Center for Advanced Materials Joining, University of Waterloo, Waterloo (Canada); Xie, J. [Cardiac Rhythm Management Division, Street Jude Medical Inc., Sylmar, CA (United States)


    Crack susceptibility of laser spot welds between Pt and Ti alloys was studied by characterizing the surface and the cross-sections of the welds produced at different pulse energies. Increase in laser pulse energy increased the dilution by the Ti alloy, giving rise to the evolution of microstructures with varying Ti contents across the entire fusion zone. Hardness results showed that regions with 66-75% Ti, i.e. consisting of primary Ti{sub 3}Pt and/or Ti{sub 3}Pt + TiPt eutectic, have a hardness higher than 700 Vickers hardness numbers (VHN), while regions with 42-66% Ti, i.e. consisting of primary TiPt, possessed hardness between 400 and 700 VHN. The extent of cracking increased with the increase in pulse energy and the cracked regions consisted of Ti contents between 50 and 75%. Brittle cracking in microstructures consisting of Ti{sub 3}Pt and TiPt phases suggested that one or both of the constituent phases are susceptible to cracking. However, crack arrest in microstructures predominantly consisting of TiPt showed that Ti{sub 3}Pt is the most susceptible phase to cracking in Pt-Ti alloy welds.

  17. A sourcebook of titanium alloy superconductivity

    CERN Document Server

    Collings, E W


    In less than two decades the concept of supercon­ In every field of science there are one or two ductivity has been transformed from a laboratory individuals whose dedication, combined with an innate curiosity to usable large-scale applications. In the understanding, permits them to be able to grasp, late 1960's the concept of filamentary stabilization condense, and explain to the rest of us what that released the usefulness of zero resistance into the field is all about. For the field of titanium alloy marketplace, and the economic forces that drive tech­ superconductivity, such an individual is Ted Collings. nology soon focused on niobium-titanium alloys. They His background as a metallurgist has perhaps given him are ductile and thus fabricable into practical super­ a distinct advantage in understanding superconduc­ conducting wires that have the critical currents and tivity in titanium alloys because the optimization of fields necessary for large-scale devices. More than superconducting parameters in ...

  18. Properties isotropy of magnesium alloy strip workpieces

    Directory of Open Access Journals (Sweden)

    Р. Кавалла


    Full Text Available The paper discusses the issue of obtaining high quality cast workpieces of magnesium alloys produced by strip roll-casting. Producing strips of magnesium alloys by combining the processes of casting and rolling when liquid melt is fed continuously to fast rolls is quite promising and economic. In the process of sheet stamping considerable losses of metal occur on festoons formed due to anisotropy of properties of foil workpiece, as defined by the macro- and microstructure and modes of rolling and annealing. The principal causes of anisotropic mechanical properties of metal strips produced by the combined casting and rolling technique are the character of distribution of intermetallic compounds in the strip, orientation of phases of metal defects and the residual tensions. One of the tasks in increasing the output of fit products during stamping operations consists in minimizing the amount of defects. To lower the level of anisotropy in mechanical properties various ways of treating the melt during casting are suggested. Designing the technology of producing strips of magnesium alloys opens a possibility of using them in automobile industry to manufacture light-weight body elements instead of those made of steel.

  19. Biomedical Applications of Shape Memory Alloys

    Directory of Open Access Journals (Sweden)

    Lorenza Petrini


    behaviors, due to the peculiar crystallographic structure of the alloys, assure the recovery of the original shape even after large deformations and the maintenance of a constant applied force in correspondence of significant displacements. These properties, joined with good corrosion and bending resistance, biological and magnetic resonance compatibility, explain the large diffusion, in the last 20 years, of SMA in the production of biomedical devices, in particular for mini-invasive techniques. In this paper a detailed review of the main applications of NiTi alloys in dental, orthopedics, vascular, neurological, and surgical fields is presented. In particular for each device the main characteristics and the advantages of using SMA are discussed. Moreover, the paper underlines the opportunities and the room for new ideas able to enlarge the range of SMA applications. However, it is fundamental to remember that the complexity of the material and application requires a strict collaboration between clinicians, engineers, physicists and chemists for defining accurately the problem, finding the best solution in terms of device design and accordingly optimizing the NiTi alloy properties.

  20. Aluminum Alloy and Article Cast Therefrom (United States)

    Lee, Jonathan A. (Inventor); Chen, Po-Shou (Inventor)


    A cast article from an aluminum alloy, which has improved mechanical properties at elevated temperatures, has the following composition in weight percent: Silicon 14 - 25.0, Copper 5.5 - 8.0, Iron 0.05 - 1.2, Magnesium 0.5 - 1.5, Nickel 0.05 - 0.9, Manganese 0.05 - 1.0, Titanium 0.05 - 1.2, Zirconium 0.05 - 1.2, Vanadium 0.05 - 1.2, Zinc 0.05 - 0.9, Phosphorus 0.001 - 0.1, and the balance is Aluminum, wherein the silicon-to-magnesium ratio is 10 - 25, and the copper-to-magnesium ratio is 4 - 15. The aluminum alloy contains a simultaneous dispersion of three types of Al3X compound particles (X=Ti, V, Zr) having a LI2, crystal structure, and their lattice parameters are coherent to the aluminum matrix lattice. A process for producing this cast article is also disclosed, as well as a metal matrix composite, which includes the aluminum alloy serving as a matrix and containing up to about 60% by volume of a secondary filler material.

  1. Alloy development for high burnup cladding (PWR)

    Energy Technology Data Exchange (ETDEWEB)

    Hahn, R. [Kraftwerk Union AG, Mulheim (Germany); Jeong, Y.H.; Baek, K.H.; Kim, S.J.; Choi, B.K.; Kim, J.M. [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)


    An overview on current alloy development for high burnup PWR fuel cladding is given. It is mainly based on literature data. First, the reasons for an increase of the current mean discharge burnup from 35 MWd / kg(U) to 70 MWd / kg(U) are outlined. From the material data, it is shown that a batch average burnup of 60-70 MWd / kg(U), as aimed by many fuel vendors, can not be achieved with stand (=ASTM-) Zry-4 cladding tubes without violating accepted design criteria. Specifically criteria which limit maximum oxide scale thickness and maximum hydrogen content, and to a less degree, maximum creep and growth rate, can not be achieved. The development potential of standard Zry-4 is shown. Even when taking advantage of this potential, it is shown that an 'improved' Zry-4 is reaching its limits when it achieves the target burnup. The behavior of some Zr alloys outside the ASTM range is shown, and the advantages and disadvantages of the 3 alloy groups (ZrSn+transition metals, ZrNb, ZrSnNb+transition metals) which are currently considered to have the development potential for high burnup cladding materials are depicted. Finally, conclusions are drawn. (author). 14 refs., 11 tabs., 82 figs.

  2. Polymorphism in a high-entropy alloy (United States)

    Zhang, Fei; Wu, Yuan; Lou, Hongbo; Zeng, Zhidan; Prakapenka, Vitali B.; Greenberg, Eran; Ren, Yang; Yan, Jinyuan; Okasinski, John S.; Liu, Xiongjun; Liu, Yong; Zeng, Qiaoshi; Lu, Zhaoping


    Polymorphism, which describes the occurrence of different lattice structures in a crystalline material, is a critical phenomenon in materials science and condensed matter physics. Recently, configuration disorder was compositionally engineered into single lattices, leading to the discovery of high-entropy alloys and high-entropy oxides. For these novel entropy-stabilized forms of crystalline matter with extremely high structural stability, is polymorphism still possible? Here by employing in situ high-pressure synchrotron radiation X-ray diffraction, we reveal a polymorphic transition from face-centred-cubic (fcc) structure to hexagonal-close-packing (hcp) structure in the prototype CoCrFeMnNi high-entropy alloy. The transition is irreversible, and our in situ high-temperature synchrotron radiation X-ray diffraction experiments at different pressures of the retained hcp high-entropy alloy reveal that the fcc phase is a stable polymorph at high temperatures, while the hcp structure is more thermodynamically favourable at lower temperatures. As pressure is increased, the critical temperature for the hcp-to-fcc transformation also rises.

  3. Superplastic Deformation of TC6 Alloy

    Directory of Open Access Journals (Sweden)

    DING Ling


    Full Text Available The superplastic tensile tests of TC6 alloy were conducted in the temperature range of 800-900℃ by using the maximum m value superplasticity deformation (Max m SPD method and the constant strain rate deformation method at the strain rate range of 0.0001-0.1 s-1. The stress-strain curve of the tensile tests was obtained and the microstructure near the fracture were analyzed by metallographic microscope. The result shows that the superplasticity of TC6 alloy is excellent, and the elongation increases first and then decreases with the increase of strain rate or temperature. When the temperature is 850℃ and strain rate is 0.001 s-1 at constant stain rate tensile tests, the elongation reaches up to 993%. However, the elongation using Max m SPD method at 850℃ is 1353%. It is shown that the material can achieve better superplasticity by using Max m SPD tensile compared to constant stain rate tensile under the same temperature. The superplastic deformation of TC6 alloy can enhance the dynamic recrystallization behavior significantly, the dynamic recrystallization behavior is promoted when strain rate and temperature are increased.

  4. Lattice mismatch modeling of aluminum alloys

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Dongwon; Roy, Shibayan; Watkins, Thomas R.; Shyam, Amit


    We present a theoretical framework to accurately predict the lattice mismatch between the fcc matrix and precipitates in the multi-component aluminum alloys as a function of temperature and composition. We use a computational thermodynamic approach to model the lattice parameters of the multi-component fcc solid solution and θ'-Al2Cu precipitate phase. Better agreement between the predicted lattice parameters of fcc aluminum in five commercial alloys (206, 319, 356, A356, and A356 + 0.5Cu) and experimental data from the synchrotron X-ray diffraction (SXD) has been obtained when simulating supersaturated rather than equilibrium solid solutions. We use the thermal expansion coefficient of thermodynamically stable θ-Al2Cu to describe temperature-dependent lattice parameters of meta-stable θ' and to show good agreement with the SXD data. Both coherent and semi-coherent interface mismatches between the fcc aluminum matrix and θ' in Al-Cu alloys are presented as a function of temperature. Our calculation results show that the concentration of solute atoms, particularly Cu, in the matrix greatly affects the lattice mismatch

  5. Alloyed surfaces: New substrates for graphene growth (United States)

    Tresca, C.; Verbitskiy, N. I.; Fedorov, A.; Grüneis, A.; Profeta, G.


    We report a systematic ab-initio density functional theory investigation of Ni(111) surface alloyed with elements of group IV (Si, Ge and Sn), demonstrating the possibility to use it to grow high quality graphene. Ni(111) surface represents an ideal substrate for graphene, due to its catalytic properties and perfect matching with the graphene lattice constant. However, Dirac bands of graphene growth on Ni(111) are completely destroyed due to the strong hybridization between carbon pz and Ni d orbitals. Group IV atoms, namely Si, Ge and Sn, once deposited on Ni(111) surface, form an ordered alloyed surface with √{ 3} ×√{ 3} -R30° reconstruction. We demonstrate that, at variance with the pure Ni(111) surface, alloyed surfaces effectively decouple graphene from the substrate, resulting unstrained due to the nearly perfect lattice matching and preserves linear Dirac bands without the strong hybridization with Ni d states. The proposed surfaces can be prepared before graphene growth without resorting on post-growth processes which necessarily alter the electronic and structural properties of graphene.

  6. Alloying effect on grain-size dependent deformation twinning in nanocrystalline Cu-Zn alloys (United States)

    Ma, X. L.; Xu, W. Z.; Zhou, H.; Moering, J. A.; Narayan, J.; Zhu, Y. T.


    Grain-size dependency of deformation twinning has been previously reported in nanocrystalline face-centred-cubic metals, which results in an optimum grain-size range for twin formation. Here, we report, for the first time in experiments, the observed optimum grain sizes for deformation twins in nanocrystalline Cu-Zn alloys which slightly increase with increasing Zn content. This result agrees with the reported trend but is much weaker than predicted by stacking-fault-energy based models. Our results indicate that alloying changes the relationship between the stacking-fault and twin-fault energy and therefore affects the optimum grain size for deformation twinning. These observations should be also applicable to other alloy systems.

  7. Titanium Alloys Manufactured by In Situ Alloying During Laser Powder Bed Fusion (United States)

    Yadroitsev, I.; Krakhmalev, P.; Yadroitsava, I.


    This work is focused on the investigation and understanding of in situ processes in Ti-15%Mo and Ti6Al4V-1.38%Cu alloys by laser powder bed fusion (LPBF). In both materials, Mo and Cu were introduced as elemental powders into the precursor powder mixture. The effect of process parameters, i.e., energy input on surface morphology and homogeneity, was investigated. The importance of different thermophysical properties of blended powders is also discussed. The chemical composition of phases and phase distribution in sintered materials were investigated by means of scanning electron microscopy. The mechanical properties of in situ alloyed as-built LPBF specimens were determined. The results obtained developed knowledge that is important for understanding the in situ alloying process during LPBF, and they create a base for synthesizing new materials.

  8. Nickel-Titanium Alloys: Corrosion "Proof" Alloys for Space Bearing, Components and Mechanism Applications (United States)

    DellaCorte, Christopher


    An intermetallic nickel-titanium alloy, 60NiTi (60 wt% Ni, 40 wt% Ti), is shown to be a promising candidate tribological material for space mechanisms. 60NiTi offers a broad combination of physical properties that make it unique among bearing materials. 60NiTi is hard, electrically conductive, highly corrosion resistant, readily machined prior to final heat treatment, and is non-magnetic. Despite its high Ti content, 60NiTi is non-galling even under dry sliding. No other bearing alloy, metallic or ceramic, encompasses all of these attributes. Since 60NiTi contains such a high proportion of Ti and possesses many metallic properties, it was expected to exhibit poor tribological performance typical of Ti alloys, namely galling type behavior and rapid lubricant degradation. In this poster-paper, the oil-lubricated behavior of 60NiTi is presented.

  9. Evaluation of the Comparative Corrosion Resistance Between AKOT Ti Alloy and Ti Gr 7 Alloy

    Energy Technology Data Exchange (ETDEWEB)

    Lian, T


    In its current design, the drip shields for the high-level nuclear waste containers for the Yucca Mountain repository will be mainly made using Ti Gr 7 (R52400). Ti Gr 7 is a highly corrosion resistant alloy, especially because it contains 0.15% palladium (Pd). The goal of this study was to determine whether an AKOT low-Pd (0.01%) titanium alloy would have a similar corrosion resistance than the more expensive Ti Gr 7 in environments that could be related to the performance of the drip shield. The focus of this testing program was on the susceptibility of the alloys to localized corrosion. Therefore, only artificially creviced specimens were used.

  10. Titanium Alloys Manufactured by In Situ Alloying During Laser Powder Bed Fusion (United States)

    Yadroitsev, I.; Krakhmalev, P.; Yadroitsava, I.


    This work is focused on the investigation and understanding of in situ processes in Ti-15%Mo and Ti6Al4V-1.38%Cu alloys by laser powder bed fusion (LPBF). In both materials, Mo and Cu were introduced as elemental powders into the precursor powder mixture. The effect of process parameters, i.e., energy input on surface morphology and homogeneity, was investigated. The importance of different thermophysical properties of blended powders is also discussed. The chemical composition of phases and phase distribution in sintered materials were investigated by means of scanning electron microscopy. The mechanical properties of in situ alloyed as-built LPBF specimens were determined. The results obtained developed knowledge that is important for understanding the in situ alloying process during LPBF, and they create a base for synthesizing new materials.

  11. Passivation and alloying element retention in gas atomized powders

    Energy Technology Data Exchange (ETDEWEB)

    Heidloff, Andrew J.; Rieken, Joel R.; Anderson, Iver E.


    A method for gas atomization of a titanium alloy, nickel alloy, or other alumina (Al.sub.2O.sub.3)-forming alloy wherein the atomized particles are exposed as they solidify and cool in a very short time to multiple gaseous reactive agents for the in-situ formation of a passivation reaction film on the atomized particles wherein the reaction film retains a precursor halogen alloying element that is subsequently introduced into a microstructure formed by subsequent thermally processing of the atomized particles to improve oxidation resistance.

  12. Advanced smart tungsten alloys for a future fusion power plant (United States)

    Litnovsky, A.; Wegener, T.; Klein, F.; Linsmeier, Ch; Rasinski, M.; Kreter, A.; Tan, X.; Schmitz, J.; Mao, Y.; Coenen, J. W.; Bram, M.; Gonzalez-Julian, J.


    The severe particle, radiation and neutron environment in a future fusion power plant requires the development of advanced plasma-facing materials. At the same time, the highest level of safety needs to be ensured. The so-called loss-of-coolant accident combined with air ingress in the vacuum vessel represents a severe safety challenge. In the absence of a coolant the temperature of the tungsten first wall may reach 1200 °C. At such a temperature, the neutron-activated radioactive tungsten forms volatile oxide which can be mobilized into atmosphere. Smart tungsten alloys are being developed to address this safety issue. Smart alloys should combine an acceptable plasma performance with the suppressed oxidation during an accident. New thin film tungsten-chromium-yttrium smart alloys feature an impressive 105 fold suppression of oxidation compared to that of pure tungsten at temperatures of up to 1000 °C. Oxidation behavior at temperatures up to 1200 °C, and reactivity of alloys in humid atmosphere along with a manufacturing of reactor-relevant bulk samples, impose an additional challenge in smart alloy development. First exposures of smart alloys in steady-state deuterium plasma were made. Smart tungsten-chroimium-titanium alloys demonstrated a sputtering resistance which is similar to that of pure tungsten. Expected preferential sputtering of alloying elements by plasma ions was confirmed experimentally. The subsequent isothermal oxidation of exposed samples did not reveal any influence of plasma exposure on the passivation of alloys.

  13. High-temperature alloys for high-power thermionic systems

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Kwang S.; Jacobson, D.L.; D' cruz, L.; Luo, Anhua; Chen, Bor-Ling.


    The need for structural materials with useful strength above 1600 k has stimulated interest in refractory-metal alloys. Tungsten possesses an extreme high modulus of elasticity as well as the highest melting temperature among metals, and hence is being considered as one of the most promising candidate materials for high temperature structural applications such as space nuclear power systems. This report is divided into three chapters covering the following: (1) the processing of tungsten base alloys; (2) the tensile properties of tungsten base alloys; and (3) creep behavior of tungsten base alloys. Separate abstracts were prepared for each chapter. (SC)

  14. Oxidation mechanisms for alloys in single-oxidant gases

    Energy Technology Data Exchange (ETDEWEB)

    Whittle, D.P.


    Scales formed on alloys invariably contain the alloy constituents in a ratio different from that in the alloy, owing to the differing thermodynamic tendencies of the alloy components to react with the oxidant and to differences in diffusion rates in scale and alloy phases. This complex interrelationship between transport rates and the thermodynamics of the alloy-oxidant system can be analyzed using multicomponent diffusion theory when transport-controlled growth of single or multi-layered scales occurs. In particular, the superimposition of the diffusion data on an isothermal section of the appropriate phase diagram indicates the likely morphologies of the reaction products, including the sequence of phases found in the scale, the occurrence of internal oxidation and the development of an irregular metal/scale interface. The scale morphologies on alloys are also time-dependent: there is an initial transient stage, a steady state period, and a final breakdown, the latter often related to mechanical influences such as scale adherence, spallation, thermal or mechanical stresses and void formation. Mechanical influences have a more devastating effect in alloy oxidation due to the changes in alloy surface composition during the steady state period.

  15. Experimental Characterization of Ultrastructure of Aviation Aluminum Alloys

    Directory of Open Access Journals (Sweden)

    YANG Mingjun


    Full Text Available In order to improve the comprehensive performance of aluminium alloys for the aviation application, it is necessary to experimentally characterize the microstructure, and thus to build a bridge between the microstructure and macro-performance of aluminum alloys. This paper introduces the brief developing course of 2xxx, 6xxx and 7xxx aluminum alloys and their microstructure evolution during artificial aging.The structural characteristics of significant phases like GP zones in Al-Cu alloys and GPB zones in Al-Cu-Mg alloys, and the precipitation behavior of S phase in Al-Cu-Mg alloys, etc, are thoroughly studied. The application of Transmission Electron Microscopy, Scanning-Transmission Electron Microscopy, 3-Dimentional Atom Probe in the investigations of structure, morphology, composition, interface structures, intergranular corrosion resistance and so on has been reviewed, especially the Ω phase in Al-Cu-Mg-Ag alloys and β" phase in Al-Mg-Si-Cu alloys. Our group has finished the works such as the simulation and characterization of complex selected area electron diffraction patterns in Al alloys, as well as the measuring of the precipitates' volume fraction with high accuracy which is based on the convergent beam electron diffraction.

  16. Excessively High Vapor Pressure of Al-based Amorphous Alloys

    Directory of Open Access Journals (Sweden)

    Jae Im Jeong


    Full Text Available Aluminum-based amorphous alloys exhibited an abnormally high vapor pressure at their approximate glass transition temperatures. The vapor pressure was confirmed by the formation of Al nanocrystallites from condensation, which was attributed to weight loss of the amorphous alloys. The amount of weight loss varied with the amorphous alloy compositions and was inversely proportional to their glass-forming ability. The vapor pressure of the amorphous alloys around 573 K was close to the vapor pressure of crystalline Al near its melting temperature, 873 K. Our results strongly suggest the possibility of fabricating nanocrystallites or thin films by evaporation at low temperatures.

  17. Microstructure of Cast Ni-Cr-Al-C Alloy

    Directory of Open Access Journals (Sweden)

    Cios G.


    Full Text Available Nickel based alloys, especially nickel based superalloys have gained the advantage over other alloys in the field of high temperature applications, and thus become irreplaceable at high temperature creep and aggressive corrosion environments, such as jet engines and steam turbines. However, the wear resistance of these alloys is insufficient at high temperatures. This work describes a microstructure of a new cast alloy. The microstructure consists of γ matrix strengthened by γ’ fine precipitates (dendrites improving the high temperature strength and of Chromium Cr7C3 primary carbides (in interdendritic eutectics which are designed to improve wear resistance as well as the high temperature strength.

  18. The hydrogen embrittlement of Ni-Cr-Fe alloys

    Energy Technology Data Exchange (ETDEWEB)

    Symons, D.M.


    It has been proposed that the stress corrosion cracking (SCC) of nickel-based alloys in low-temperature hydrogenated water is due to hydrogen embrittlement. The purpose of this work was to investigate the role of chromium on hydrogen embrittlement of Ni-Cr-Fe alloys and thus develop a better understanding of the low-temperature SCC phenomenon. The effect of chromium on the hydrogen embrittlement was examined using tensile tests followed by material evaluation via scanning electron microscopy and light optical microscopy. Four alloys were prepared with chromium contents ranging from 6 wt. percent to 35 wt. percent. In the noncharged condition, ductility, as measured by the percent elongation or reduction in area, increased as the alloy chromium content increased. Hydrogen appeared to have only minor effects on the mechanical properties of the low chromium alloys. The addition of hydrogen had a marked effect on the ductility of the higher chromium alloys. In the 26% chromium alloy, the elongation to failure was reduced from 53% to 14% with a change in fracture mode from ductile dimple to intergranular failure. A maximum in embrittlement was observed in the 26% Cr alloy. The maximum in embrittlement coincided with the minimum in stacking-fault energy. It is proposed that the increased hydrogen embrittlement in the high-chromium alloys is due to increased slip planarity caused by the low stacking-fault energy. Slip planarity did not appear to affect the fracture of the noncharged specimens.

  19. Titanium aluminide intermetallic alloys with improved wear resistance (United States)

    Qu, Jun; Lin, Hua-Tay; Blau, Peter J.; Sikka, Vinod K.


    The invention is directed to a method for producing a titanium aluminide intermetallic alloy composition having an improved wear resistance, the method comprising heating a titanium aluminide intermetallic alloy material in an oxygen-containing environment at a temperature and for a time sufficient to produce a top oxide layer and underlying oxygen-diffused layer, followed by removal of the top oxide layer such that the oxygen-diffused layer is exposed. The invention is also directed to the resulting oxygen-diffused titanium aluminide intermetallic alloy, as well as mechanical components or devices containing the improved alloy composition.

  20. Shape Memory Alloy-Based Periodic Cellular Structures Project (United States)

    National Aeronautics and Space Administration — This SBIR Phase I effort will develop and demonstrate an innovative shape memory alloy (SMA) periodic cellular structural technology. Periodic cellular structures...


    Directory of Open Access Journals (Sweden)

    Nataša Náprstková


    Full Text Available The Faculty of Production Technology and Management is often asked by companies with a request to solve a specific technical task. One of these tasks was the analysis of aluminum alloy worsened machinability when the rods from this alloy exhibited against assumption significantly worse (longer chips during machining. The alloy was complaint and, of course, it created economic damage. Obviously, the company was interested in the causes of this alloy behavior change that could possibly generate future complaints procedures to defend itself better, or to avoid mistakes in the production of the material. At the faculty analysis that could contribute to identifying the cause of the worsened machinability were done.

  2. Order/disorder in electrodeposited aluminum-titanium alloys

    Directory of Open Access Journals (Sweden)

    Stafford G.R.


    Full Text Available The composition, morphology, and crystallographic microstructure of Al-Ti alloys electrodeposited from two different chloroaluminate molten salt electrolytes were examined. Alloys containing up to 28 % atomic fraction Ti were electrodeposited at 150 °C from 2:1 AlCl3-NaCl with controlled additions of Ti2+. The apparent limit on alloy composition is proposed to be due to a mechanism by which Al3Ti forms through the reductive decomposition of [Ti(AlCl43]-. The composition of Al-Ti alloys electrodeposited from the AlCl3-EtMeImCl melt at 80 °C is limited by the diffusion of Ti2+ to the electrode surface. Alloys containing up to 18.4 % atomic fraction Ti are only obtainable at high Ti2+ concentrations in the melt and low current densities. Alloys electrodeposited from the higher temperature melt have an ordered L12 crystal structure while alloys of similar composition but deposited at lower temperature are disordered fcc. The appearance of antiphase boundaries in the ordered alloys suggests that the deposit may be disordered initially and then orders in the solid state, subsequent to the charge transfer step and adatom incorporation into the lattice. This is very similar to the disorder-trapping observed in rapidly solidified alloys. The measured domain size is consistent with a mechanism of diffusion-controlled doman growth at the examined deposition temperatures and times.

  3. Corrosion behavior of nickel-containing alloys in artificial sweat. (United States)

    Randin, J P


    The corrosion resistance of various nickel-containing alloys was measured in artificial sweat (perspiration) using the Tafel extrapolation method. It was found that Ni, CuNi 25 (coin alloy), NiAl (colored intermetallic compounds), WC + Ni (hard metal), white gold (jewelry alloy), FN42 and Nilo Alby K (controlled expansion alloys), and NiP (electroless nickel coating) are in an active state and dissolve readily in oxygenated artificial sweat. By contrast, austenitic stainless steels, TiC + Mo2C + Ni (hard metal), NiTi (shape-memory alloy), Hastelloy X (superalloy), Phydur (precipitation hardening alloy), PdNi and SnNi (nickel-containing coatings) are in a passive state but may pit under certain conditions. Cobalt, Cr, Ti, and some of their alloys were also investigated for the purpose of comparison. Cobalt and its alloys have poor corrosion resistance except for Stellite 20. Chromium and high-chromium ferritic stainless steels have a high pitting potential but the latter are susceptible to crevice corrosion. Ti has a pitting potential greater than 3 V. Comparison between the in vitro measurements of the corrosion rate of nickel-based alloys and the clinical observation of the occurrence of contact dermatitis is discussed.

  4. Shape Memory Alloys (Part II: Classification, Production and Application

    Directory of Open Access Journals (Sweden)

    I. Ivanic


    Full Text Available Shape memory alloys (SMAs have been extensively investigated because of their unique shape memory behaviour, i.e. their ability to recover their original shape they had before deformation. Shape memory effect is related to the thermoelastic martensitic transformation. Austenite to martensite phase transformation can be obtained by mechanical (loading and thermal methods (heating and cooling. Depending on thermomechanical conditions, SMAs demonstrate several thermomechanical phenomena, such as pseudoelasticity, superelasticity, shape memory effect (one-way and two-way and rubber-like behaviour. Numerous alloys show shape memory effect (NiTi-based alloys, Cu-based alloys, Fe-based alloys etc.. Nitinol (NiTi is the most popular and the most commonly used SMA due to its superior thermomechanical and thermoelectrical properties. NiTi alloys have greater shape memory strain and excellent corrosion resistance compared to Cu – based alloys. However, they are very costly. On the other hand, copper-based alloys (CuZn and CuAl based alloys are much less expensive, easier to manufacture and have a wider range of potential transformation temperatures. The characteristic transformation temperatures of martensitic transformation of CuAlNi alloys can lie between −200 and 200 °C, and these temperatures depend on Al and Ni content. Among the Cu – based SMAs, the most frequently applied are CuZnAl and CuAlNi alloys. Although CuZnAl alloys with better mechanical properties are the most popular among the Cu-based SMAs, they lack sufficient thermal stability, while CuAlNi shape memory alloys, in spite of their better thermal stability, have found only limited applications due to insufficient formability owing to the brittle γ2 precipitates. The most important disadvantage of polycrystalline CuAlNi alloys is a small reversible deformation (one-way shape memory effect: up to 4 %; two-way shape memory effect: only approximately 1.5 % due to intergranular

  5. Corrosion of copper alloys in sulphide containing district heting systems

    DEFF Research Database (Denmark)

    Thorarinsdottir, R.I.; Maahn, Ernst Emanuel


    Copper and some copper alloys are prone to corrosion in sulphide containing geothermal water analogous to corrosion observed in district heating systems containing sulphide due to sulphate reducing bacteria. In order to study the corrosion of copper alloys under practical conditions a test...... was carried out at four sites in the Reykjavik District Heating System. The geothermal water chemistry is different at each site. The corrosion rate and the amount and chemical composition of deposits on weight loss coupons of six different copper alloys are described after exposure of 12 and 18 months......, respectively. Some major differences in scaling composition and the degree of corrosion attack are observed between alloys and water types....

  6. Development of ODS-Fe{sub 3}Al alloys

    Energy Technology Data Exchange (ETDEWEB)

    Wright, I.G.; Pint, B.A.; Tortorelli, P.F.; McKamey, C.G. [Oak Ridge National Lab., TN (United States)


    The overall goal of this program is to develop an oxide dispersion-strengthened (ODS) version of Fe{sub 3}Al that has sufficient creep strength and resistance to oxidation at temperatures in the range 1000 to 1200 C to be suitable for application as heat exchanger tubing in advanced power generation cycles. The main areas being addressed are: (a) alloy processing to achieve the desired alloy grain size and shape, and (b) optimization of the oxidation behavior to provide increased service life compared to semi-commercial ODS-FeCrAl alloys intended for the same applications. The recent studies have focused on mechanically-alloyed powder from a commercial alloy vendor. These starting alloy powders were very clean in terms of oxygen content compared to ORNL-produced powders, but contained similar levels of carbon picked up during the milling process. The specific environment used in milling the powder appears to exert a considerable influence on the post-consolidation recrystallization behavior of the alloy. A milling environment which produced powder particles having a high surface carbon content resulted in a consolidated alloy which readily recrystallized, whereas powder with a low surface carbon level after milling resulted in no recrystallization even at 1380 C. A feature of these alloys was the appearance of voids or porosity after the recrystallization anneal, as had been found with ORNL-produced alloys. Adjustment of the recrystallization parameters did not reveal any range of conditions where recrystallization could be accomplished without the formation of voids. Initial creep tests of specimens of the recrystallized alloys indicated a significant increase in creep strength compared to cast or wrought Fe{sub 3}Al, but the specimens failed prematurely by a mechanism that involved brittle fracture of one of the two grains in the test cross section, followed by ductile fracture of the remaining grain. The reasons for this behavior are not yet understood. The

  7. Electrodeposition of NiPd alloy from aqueous chloride electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Mech, K., E-mail: [AGH University of Science and Technology, Academic Centre for Materials and Nanotechnology, al. A. Mickiewicza 30, 30-059 Krakow (Poland); Wróbel, M [AGH, University of Science and Technology, Faculty of Metals Engineering and Industrial Computer Science, al. A. Mickiewicza 30, Krakow (Poland); Wojnicki, M [AGH University of Science and Technology, Faculty of Non-Ferrous Metals, Department of Physical Chemistry and Metallurgy of Non-Ferrous Metals, al. A. Mickiewicza 30, 30-059 Krakow (Poland); Mech-Piskorz, J. [Institute of Physical Chemistry, Polish Academy of Sciences, ul. Kasprzaka 44/52, 01-224 Warsaw (Poland); Żabiński, P.; Kowalik, R. [AGH University of Science and Technology, Faculty of Non-Ferrous Metals, Department of Physical Chemistry and Metallurgy of Non-Ferrous Metals, al. A. Mickiewicza 30, 30-059 Krakow (Poland)


    Highlights: • Mechanism of electrode reactions resulting in NiPd alloys was described. • Electrolysis conditions enabling alloys synthesis were determined. • Alloys were characterized towards composition, structure and surface properties. - Abstract: Presented results describing properties of alloys deposited at potentiostatic conditions in Ni{sup 2+} – Pd{sup 2+} – Cl{sup −} – H{sub 2}O system. Electrolysis parameters were defined based on results of thermodynamic analysis as well as voltammetry coupled with electrochemical quartz crystal microbalance (EQCM). Influence of electrode potential and electrolyte components concentration on alloy composition, morphology and its structure was investigated. Alloys were deposited at different Ni(II) and Pd(II) complexes concentrations. Results indicated possibilities of electrochemical synthesis of alloys of wide composition range. Deposits structure as well as crystallites size were discussed based on results of XRD measurements. Alloys composition was determined with the use of energy dispersive spectroscopy (EDS). Morphology of alloys was characterized with the use of scanning electron microscopy (SEM).

  8. The effects of alloying elements on microstructures and mechanical properties of tungsten inert gas welded AZ80 magnesium alloys joint (United States)

    Li, Hui; Zhang, Jiansheng; Ding, Rongrong


    The effects of alloying elements on the macrostructures, microstructures and tensile strength of AZ80 Mg alloy weldments were studied in the present study. The results indicate that with the decrease of Al element content of filler wire, the welding defects of seam are gradually eliminated and the β-Mg17Al12 phases at α-Mg boundaries are refined and become discontinuous, which are beneficial to the improvement of tensile strength. With AZ31 Mg alloy filler wire, the maximum tensile strength of AZ80 weldment is 220 MPa and fracture occurs at the welding seam of joint. It is experimentally proved that robust AZ80 Mg alloy joints can be obtained by tungsten inert gas (TIG) welding process with AZ31 Mg alloy filler wire. However, further study is required to improve the microstructures and reduce welding defects of joint in order to further improve the joining strength of AZ80 Mg alloy joint.

  9. Effects of Alloying Element Ca on the Corrosion Behavior and Bioactivity of Anodic Films Formed on AM60 Mg Alloys

    Directory of Open Access Journals (Sweden)

    Anawati Anawati


    Full Text Available Effects of alloying element Ca on the corrosion behavior and bioactivity of films formed by plasma electrolytic oxidation (PEO on AM60 alloys were investigated. The corrosion behavior was studied by conducting electrochemical tests in 0.9% NaCl solution while the bioactivity was evaluated by soaking the specimens in simulated body fluid (SBF. Under identical anodization conditions, the PEO film thicknesses increased with increasing Ca content in the alloys, which enhanced the corrosion resistance in NaCl solution. Thicker apatite layers grew on the PEO films of Ca-containing alloys because Ca was incorporated into the PEO film and because Ca was present in the alloys. Improvement of corrosion resistance and bioactivity of the PEO-coated AM60 by alloying with Ca may be beneficial for biodegradable implant applications.

  10. Benzene adsorption on binary Pt3M alloys and surface alloys: a DFT study. (United States)

    Sabbe, Maarten K; Laín, Lucia; Reyniers, Marie-Françoise; Marin, Guy B


    Benzene adsorption on Pt3M/Pt(111) surfaces and Pt3M(111) bulk alloys (M = Fe, Co, Ni, Cu, Pd, Ag, Au) is analyzed using density functional theory calculations on 4-layered slabs in the framework of catalyst development for aromatics hydrogenation. Segregation in the top layers was allowed for, accounting for the actual stoichiometric composition of the top layers rather than using simplified 'skin' or 'sandwich' structures. On the surfaces that do not segregate (M = Pd, Ag, Au), the preferred benzene adsorption site is the hollow Pt3-hcp(0) site. On antisegregated "Pt-skin" surfaces (M = Fe, Co, Ni, Cu, Pd), which have a top layer composed entirely of Pt, benzene prefers bridge sites with a maximized number of solute atoms M in the subsurface layers. Benzene adsorption is weaker than on pure Pt(111), by 0.1-0.5 eV on the surface alloys and by 0.6-1.0 eV on bulk alloys, except for Pt3Pd alloys, which behave similarly to pure Pt. On the fully segregated Pt3Ag and Pt3Au alloys, which have a Ag resp. Au monolayer on top, only physisorption occurs. Benzene adsorption does not change the segregation state of the catalyst. From various DOS-based catalyst descriptors, the occupied d-band center of the clean catalyst slab shows the best correlation with benzene adsorption energies, allowing the prediction of benzene adsorption energies on a range of other Pt-based bimetallic alloys.

  11. adwTools Developed: New Bulk Alloy and Surface Analysis Software for the Alloy Design Workbench (United States)

    Bozzolo, Guillermo; Morse, Jeffrey A.; Noebe, Ronald D.; Abel, Phillip B.


    A suite of atomistic modeling software, called the Alloy Design Workbench, has been developed by the Computational Materials Group at the NASA Glenn Research Center and the Ohio Aerospace Institute (OAI). The main goal of this software is to guide and augment experimental materials research and development efforts by creating powerful, yet intuitive, software that combines a graphical user interface with an operating code suitable for real-time atomistic simulations of multicomponent alloy systems. Targeted for experimentalists, the interface is straightforward and requires minimum knowledge of the underlying theory, allowing researchers to focus on the scientific aspects of the work. The centerpiece of the Alloy Design Workbench suite is the adwTools module, which concentrates on the atomistic analysis of surfaces and bulk alloys containing an arbitrary number of elements. An additional module, adwParams, handles ab initio input for the parameterization used in adwTools. Future modules planned for the suite include adwSeg, which will provide numerical predictions for segregation profiles to alloy surfaces and interfaces, and adwReport, which will serve as a window into the database, providing public access to the parameterization data and a repository where users can submit their own findings from the rest of the suite. The entire suite is designed to run on desktop-scale computers. The adwTools module incorporates a custom OAI/Glenn-developed Fortran code based on the BFS (Bozzolo- Ferrante-Smith) method for alloys, ref. 1). The heart of the suite, this code is used to calculate the energetics of different compositions and configurations of atoms.

  12. Fabrication of nanocrystalline alloys Cu–Cr–Mo super satured solid solution by mechanical alloying

    Energy Technology Data Exchange (ETDEWEB)

    Aguilar, C., E-mail: [Departamento de Ingeniería Metalúrgica y Materiales, Universidad Técnica Federico Santa María, Av. España 1680, Valparaíso (Chile); Guzmán, D. [Departamento de Ingeniería en Metalurgia, Facultad de Ingeniería, Universidad de Atacama y Centro Regional de Investigación y Desarrollo Sustentable de Atacama (CRIDESAT), Av. Copayapu 485, Copiapó (Chile); Castro, F.; Martínez, V.; Cuevas, F. de las [Centro de Estudios e Investigaciones Técnicas de Gipuzkoa, Paseo de Manuel Lardizábal, N° 15, 20018 San Sebastián (Spain); Lascano, S. [Departamento de Ingeniería Mecánica, Universidad Técnica Federico Santa María, Av. España 1680, Valparaíso (Chile); Muthiah, T. [Departamento de Ingeniería Metalúrgica y Materiales, Universidad Técnica Federico Santa María, Av. España 1680, Valparaíso (Chile)


    This work discusses the extension of solid solubility of Cr and Mo in Cu processed by mechanical alloying. Three alloys processed, Cu–5Cr–5Mo, Cu–10Cr–10Mo and Cu–15Cr–15Mo (weight%) using a SPEX mill. Gibbs free energy of mixing values 10, 15 and 20 kJ mol{sup −1} were calculated for these three alloys respectively by using the Miedema's model. The crystallite size decreases and dislocation density increases when the milling time increases, so Gibbs free energy storage in powders increases by the presence of crystalline defects. The energy produced by crystallite boundaries and strain dislocations were estimated and compared with Gibbs free energy of mixing values. The energy storage values by the presence of crystalline defects were higher than Gibbs free energy of mixing at 120 h for Cu–5Cr–5Mo, 130 h for Cu–10Cr–10Mo and 150 h for Cu–15Cr–15Mo. During milling, crystalline defects are produced that increases the Gibbs free energy storage and thus the Gibbs free energy curves are moved upwards and hence the solubility limit changes. Therefore, the three alloys form solid solutions after these milling time, which are supported with the XRD results. - Highlights: • Extension of solid solution Cr and Mo in Cu achieved by mechanical alloying. • X-ray characterization of Cu–Cr–Mo system processed by mechanical alloying. • Thermodynamics analysis of formation of solid solution of the Cu–Cr–Mo system.

  13. Surface alloying of Ti6Al4V alloy by pulsed laser. [Ti-Al-V

    Energy Technology Data Exchange (ETDEWEB)

    Zambon, A. (DIMEG - Univ. di Padova (Italy)); Ramous, E. (DIMEG - Univ. di Padova (Italy)); Bianco, M. (Ist. RTM, Vico Canavese (Torino) (Italy)); Rivela, C. (Ist. RTM, Vico Canavese (Torino) (Italy))


    The feasibility of gas surface alloying of Titanium alloys by laser has been already studied. However relevant difficulties in the aforesaid process result in surface chemical heterogeneity and roughness. We tried to overcome these problems by optimizing the nitriding and carburizing treatments with a pulsed Nd-YAG laser. Treated samples were examined by metallographic techniques, XRD and by hardness and roughness tests. Results showed that carburized layers exhibit better properties compared with nitrided ones, both as hardness profiles and surface roughness. Preliminary wear tests confirmed the better behaviour of carburized layers. (orig.)

  14. Fatigue Resistance of Liquid-assisted Self-repairing Aluminum Alloys Reinforced with Shape Memory Alloys (United States)

    Wright, M. Clara; Manuel, Michele; Wallace, Terryl


    A self-repairing aluminum-based composite system has been developed using a liquid-assisted healing theory in conjunction with the shape memory effect of wire reinforcements. The metal-metal composite was thermodynamically designed to have a matrix with a relatively even dispersion of a low-melting eutectic phase, allowing for repair of cracks at a predetermined temperature. Additionally, shape memory alloy (SMA) wire reinforcements were used within the composite to provide crack closure. Investigators focused the research on fatigue cracks propagating through the matrix in order to show a proof-of-concept Shape Memory Alloy Self-Healing (SMASH) technology for aeronautical applications.

  15. Mechanical alloying of Cu-xCr (x = 3, 5 and 8 wt.%) alloys

    Energy Technology Data Exchange (ETDEWEB)

    Aguilar, C., E-mail: ceaguilar@uach.c [Instituto de Materiales y Procesos Termomecanicos, Facultad de Ciencias de la Ingenieria, Universidad Austral de Chile, General Lagos 2086, Valdivia (Chile); Ordonez, S. [Departamento de Ingenieria Metalurgica, Facultad de Ingenieria, Universidad de Santiago de Chile, Av. L. Bernardo O' Higgins 3363, Santiago (Chile); Guzman, D. [Departamento de Metalurgia, Facultad de Ingenieria, Universidad de Atacama, Av. Copayapu 485, Copiapo (Chile); Rojas, P.A. [Escuela de Ingenieria Mecanica, Facultad de Ingenieria, Pontificia Universidad Catolica de Valparaiso, Av. Los Carrera 01567, Quilpue (Chile)


    This work studies the structural evolution of Cu-xCr (x = 3, 5 and 8 wt.%) alloys processed by mechanical alloying using X-ray diffraction profiles, scanning microscopy and microhardness analysis. X-ray diffraction analysis using the modified Williamson-Hall and Warren-Averbach methods were used to determine structural properties, such as crystallite size, stacking fault probability and energy, dislocation density, lattice parameters and crystallite size distribution of metallic powder as a function of Cr amount and milling time. Lattice defects increase the Gibbs free energy and the Gibbs free energy curves shift upward, therefore the solubility limit change.

  16. Evaluation of the feasibility of joining titanium alloy to heavymet tungsten alloy

    Energy Technology Data Exchange (ETDEWEB)


    Information is presented on a program to select and evaluate methods of brazing and/or explosively welding Ti-6Al-4V titanium alloy to Heavymet, a tungsten-base metal containing up to about 20% alloying elements (nickel, copper, etc.) to improve its ductility and other mechanical properties. Designs permitting the reliable production of joints between these base metals were of interest too. While this investigation was primarily concerned with an engineering study of the problems associated with joining these base metals in the required configuration, limited experimental studies were conducted also. The joining methods are reviewed individually. Recommendations for developing a viable titanium-tungsten joining procedure are discussed.

  17. Studies of the AA2519 Alloy Hot Rolling Process and Cladding with EN AW-1050A Alloy

    Directory of Open Access Journals (Sweden)

    Płonka B.


    Full Text Available The objective of the study was to determine the feasibility of plastic forming by hot rolling of the AA2519 aluminium alloy sheets and cladding these sheets with a layer of the EN AW-1050A alloy. Numerous hot-rolling tests were carried out on the slab ingots to define the parameters of the AA2519 alloy rolling process. It has been established that rolling of the AA2519 alloy should be carried out in the temperature range of 400-440°C. Depending on the required final thickness of the sheet metal, appropriate thickness of the EN AW-1050A alloy sheet, used as a cladding layer, was selected. As a next step, structure and mechanical properties of the resulting AA2519 alloy sheets clad with EN AW-1050A alloy was examined. The thickness of the coating layer was established at 0,3÷0,5mm. Studies covered alloy grain size and the core alloy-cladding material bond strength.

  18. Rotary Friction Welding of Weight Heavy Alloy with Wrought AlMg3 Alloy for Subcaliber Ammunition

    Directory of Open Access Journals (Sweden)

    Olgierd Janusz Goroch


    Full Text Available The results of studies concerning friction welding of Weight Heavy Alloy (WHA with AlMg3 alloy are presented. The friction welding of density 17,5 Mg/m3 with aluminum alloy showed that it is possible to reach the joints with the strength exceeding the yield strength of wrought AlMg3 alloy. This strength looks to be promising from point of view of condition which have to be fulfilled in case of armor subcaliber ammunition, where WHA rods play the role Kinetic Energy Penetrators and aluminum is used for projectile ballistic cup.

  19. An evaluation of mechanical and high-temperature corrosion properties of Ni-Cr alloy with composition of alloying elements

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Sujin; Kim, Dongjin [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)


    Helium is used as a coolant in a VHTR owing to its high thermal conductivity, inertness, and low neutron absorption. However, helium inevitably includes impurities that create an imbalance in the surface reactivity at the interface of the coolant and the exposed materials. As the Alloy 617 has been exposed to high temperatures at 950 .deg. C in the impure helium environment of a VHTR, degradation of material is accelerated and mechanical properties decreased. An alloy superior to alloy 617 should be developed. In this study, the mechanical and high-temperature corrosion properties for Ni-Cr alloys fabricated in laboratory were evaluated as a function of the grain boundary strengthening and alloying element composition. The mechanical property and corrosion property for Ni-Cr alloys fabricated in a laboratory were evaluated as a function of the main element composition. The ductility was increased and decreased by increasing the amount of Mo and Cr, respectively. Surface oxide was detached during the corrosion test, because there was not aluminum element in the alloy. Aluminum seems to act as an anti-corrosive role in Ni-based alloy. In conclusion, the addition of Al into the alloy is required to improvement of high temperature corrosion resistance.

  20. A new technique to modify hypereutectic Al-24%Si alloys by a Si-P master alloy

    Energy Technology Data Exchange (ETDEWEB)

    Wu Yaping; Wang Shujun; Li Hui [Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, 73 Jingshi Road, Jinan 250061 (China); Liu Xiangfa [Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, 73 Jingshi Road, Jinan 250061 (China)], E-mail:


    The modification effect of a Si-P master alloy on Al-24%Si alloy was investigated by using electron probe micro-analyzer (EPMA) and optical microscopy (OM). The dissolution problem of the Si-P master alloys was solved by changing the sequence of addition. When the Si-P master alloy was added into Al melt before the addition of silicon, the best modification effect could be achieved. The modification parameters of the master alloy on Al-24%Si alloy were optimized through designing and analyzing the orthogonal experiment, and their influences on the modification effect were discussed. The results show that the influence of temperature on the modification effect is the greatest, followed by the addition level, and the holding time is the least. The optimized modification parameters are the modification temperature of 810 deg. C, the addition level of 0.35 wt.%, the holding time of 30 min + 50 min whose meaning is that the Si-P master alloy is added firstly to the molten Al, and silicon is added 30 min later, then holding another 50 min. In addition, the modification mechanism of the Si-P master alloy on Al-24%Si alloy was also discussed.

  1. CO2 laser welding of magnesium alloys (United States)

    Dhahri, Mohammed; Masse, Jean Eric; Mathieu, J. F.; Barreau, Gerard; Autric, Michel L.


    Metallic alloys with a low mass density can be considered to be basic materials in aeronautic and automotive industry. Magnesium alloys have better properties than aluminum alloys in respect of their low density and high resistance to traction. The main problems of magnesium alloy welding are the inflammability, the crack formation and the appearance of porosity during the solidification. The laser tool is efficient to overcome the difficulties of manufacturing by conventional processing. Besides, the laser processing mainly using shielding gases allows an effective protection of the metal against the action of oxygen and a small heat affected zone. In this paper, we present experimental results about 5 kW CO2 laser welding of 4 mm-thick magnesium alloy plates provided by Eurocopter France. The focused laser beam has about 0.15 mm of diameter. We have investigated the following sample: WE43, alloy recommended in aeronautic and space applications, is constituted with Mg, Y, Zr, rare earth. More ductile, it can be used at high temperatures until 250 degrees Celsius for times longer than 5000 hours without effects on its mechanical properties. A sample of RZ5 (French Norm: GZ4TR, United States Norm ZE41) is composed of Mg, Zn, Zr, La, rare earth. This alloy has excellent properties of foundry and it allows to the realization of components with complex form. Also, it has a good resistance and important properties of tightness. The parameters of the process were optimized in the following fields: laser power: 2 to 5 kW, welding speed: 1 to 4.5 m/min, focal position: -3 mm to +3 mm below or on the top of the metal surface, shielding gas: helium with a flow of 10 to 60 l/min at 4 bars. Metallurgical analyses and mechanical control are made (macroscopic structure, microscopic structure, interpretations of the structures and localization of possible defects, analyse phases, chemical composition, hardness, tensile test etc.) to understand the parameters influence of welding

  2. Reduced Activation W Alloys for Plasma Facing Materials

    Energy Technology Data Exchange (ETDEWEB)

    Waseem, Owais Ahmed; Kim, Seung Su; Lee, Jun Ho; Hong, Soon Hyung; Ryu, Ho Jin [KAIST, Daejeon (Korea, Republic of)


    In order to improve the in-service characteristics of W, thorough research on W-based composites, new W alloys and functionally graded materials are in progress. The limitations of conventional W alloys such as such as high brittleness, high activation energy for dislocation's mobility, reduced mechanical strength due to reaction phases, poor fabricability, defective passive layer, poor workability and unavailability of good number of alloy systems have persuaded us to divert research focus towards W-based high entropy alloys. The core effects of high entropy alloys include enhanced mixing entropy, sluggish diffusion, severe lattice distortion and cocktail effects. These key characteristics of high entropy alloys promote the formation of solid solution of 5 to 13 principle elements with exceptionally high strength, hardness, thermal stability, wear resistance, fatigue and creep resistance. Although the synthesis and exploitation of high entropy alloys have been in progress, this study comprises of our work in which we developed a reduced activation W-based high entropy alloy by not incorporating Mo, Cu, Nb and by reducing Ti content. In this research a powder metallurgical technique has been successfully used for producing novel W-based alloy with enhanced mechanical properties. An undiscovered potential of an unusual and so far disregarded powder metallurgical technique i. e. simple mixing in the development of W based material for future fusion power plants has been exploited by fabricating and analyzing a novel tungsten based high entropy alloy system x%W-(100-x)/4%(TaTiCrV). The characterization of HEA samples by XRD showed BCC crystal structure of the alloys. Microstructural examination SEM-EDS revealed the presence of bright and dark regions as W and Ti-rich phases, respectively. The evaluation of microstructures by using image processing software and Vickers hardness via micro-Vickers hardness tester showed the similar dependency of phase fraction and

  3. A Review of Dissimilar Welding Techniques for Magnesium Alloys to Aluminum Alloys

    Directory of Open Access Journals (Sweden)

    Liming Liu


    Full Text Available Welding of dissimilar magnesium alloys and aluminum alloys is an important issue because of their increasing applications in industries. In this document, the research and progress of a variety of welding techniques for joining dissimilar Mg alloys and Al alloys are reviewed from different perspectives. Welding of dissimilar Mg and Al is challenging due to the formation of brittle intermetallic compound (IMC such as Mg17Al12 and Mg2Al3. In order to increase the joint strength, three main research approaches were used to eliminate or reduce the Mg-Al intermetallic reaction layer. First, solid state welding techniques which have a low welding temperature were used to reduce the IMCs. Second, IMC variety and distribution were controlled to avoid the degradation of the joining strength in fusion welding. Third, techniques which have relatively controllable reaction time and energy were used to eliminate the IMCs. Some important processing parameters and their effects on weld quality are discussed, and the microstructure and metallurgical reaction are described. Mechanical properties of welds such as hardness, tensile, shear and fatigue strength are discussed. The aim of the report is to review the recent progress in the welding of dissimilar Mg and Al to provide a basis for follow-up research.


    Directory of Open Access Journals (Sweden)

    K. V. Kobyakov


    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.



    K. V. Kobyakov; N. F. Nevar


    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.


    Directory of Open Access Journals (Sweden)

    A. G. Slutskij


    Full Text Available The thermodynamic calculations of the temperature of the disoxidation onset of a raw of alloying element by solid carbon are canned out. It is determined that using of additives on the basis of wastes allows to reduce the cost of castings due to replacement of expensive raw materials.

  7. A Review of Dissimilar Welding Techniques for Magnesium Alloys to Aluminum Alloys (United States)

    Liu, Liming; Ren, Daxin; Liu, Fei


    Welding of dissimilar magnesium alloys and aluminum alloys is an important issue because of their increasing applications in industries. In this document, the research and progress of a variety of welding techniques for joining dissimilar Mg alloys and Al alloys are reviewed from different perspectives. Welding of dissimilar Mg and Al is challenging due to the formation of brittle intermetallic compound (IMC) such as Mg17Al12 and Mg2Al3. In order to increase the joint strength, three main research approaches were used to eliminate or reduce the Mg-Al intermetallic reaction layer. First, solid state welding techniques which have a low welding temperature were used to reduce the IMCs. Second, IMC variety and distribution were controlled to avoid the degradation of the joining strength in fusion welding. Third, techniques which have relatively controllable reaction time and energy were used to eliminate the IMCs. Some important processing parameters and their effects on weld quality are discussed, and the microstructure and metallurgical reaction are described. Mechanical properties of welds such as hardness, tensile, shear and fatigue strength are discussed. The aim of the report is to review the recent progress in the welding of dissimilar Mg and Al to provide a basis for follow-up research. PMID:28788646

  8. FeSiBAlNiMo High Entropy Alloy Prepared by Mechanical Alloying

    Czech Academy of Sciences Publication Activity Database

    Bureš, R.; Hadraba, Hynek; Fáberová, M.; Kollár, P.; Füzer, J.; Roupcová, Pavla; Strečková, M.


    Roč. 131, č. 4 (2017), s. 771-773 ISSN 0587-4246 R&D Projects: GA ČR(CZ) GA14-25246S Institutional support: RVO:68081723 Keywords : Entropy * Mechanical alloying * Nanocrystals * Sintering Subject RIV: JG - Metallurgy Impact factor: 0.469, year: 2016

  9. Creep and stress rupture of oxide dispersion strengthened mechanically alloyed Inconel alloy MA 754 (United States)

    Howson, T. E.; Tien, J. K.; Stulga, J. E.


    The creep and stress rupture behavior of the mechanically alloyed oxide dispersion strengthened nickel-base alloy MA 754 was studied at 760, 982 and 1093 C. Tensile specimens with a fine, highly elongated grain structure, oriented parallel and perpendicular to the longitudinal grain direction were tested at various stresses in air under constant load. It was found that the apparent stress dependence was large, with power law exponents ranging from 19 to 33 over the temperature range studied. The creep activation energy, after correction for the temperature dependence of the elastic modulus, was close to but slightly larger than the activation energy for self diffusion. Rupture was intergranular and the rupture ductility as measured by percentage elongation was generally low, with values ranging from 0.5 to 16 pct. The creep properties are rationalized by describing the creep rates in terms of an effective stress which is the applied stress minus a resisting stress consistent with the alloy microstructure. Values of the resisting stress obtained through a curve fitting procedure are found to be close to the values of the particle by-pass stress for this oxide dispersion strengthened alloy, as calculated from the measured oxide particle distribution.

  10. Alloy Design and Property Evaluation of Ti-Mo-Nb-Sn Alloy for ...

    African Journals Online (AJOL)

    ... Sn and Nb elements in synergy hindered formation athermal w phase and significantly enhanced b phase stability. The low elastic modulus and good ductility as observed implied that this alloy can be more suitable for biomedical application than the conventional metallic biomaterials from better mechanical compatibility ...

  11. Hardfacing of aluminium alloys by means of metal matrix composites produced by laser surface alloying

    CSIR Research Space (South Africa)

    Pityana, SL


    Full Text Available Metal matrix composite layers were formed on an aluminium substrate by means of laser surface alloying method. Aluminium 1200 was used as a host material and TiC particles were used as the reinforcement. The microstructure of the modified layer...

  12. Local electrochemical behaviour of 7xxx aluminium alloys

    NARCIS (Netherlands)

    Andreatta, F.


    Aluminium alloys of the 7xxx series (Al-Zn-Mg-Cu) are susceptible to localized types of corrosion like pitting, intergranular corrosion and exfoliation corrosion. This represents a limitation for the application of these alloys in the aerospace components because localized corrosion might have a


    Directory of Open Access Journals (Sweden)

    A. A. Andrushevich


    Full Text Available The assessment of influence of powder particles in the mode of super deep penetration (SDP on change of corrosion resistance of aluminum cast alloy AK12 is executed. The aluminum alloy reinforced by fiber zones with the reconstructed structure has the increased corrosion resistance.

  14. Local electrochemical behaviour of 7xxx aluminium alloys

    NARCIS (Netherlands)

    De Wit, J.H.W.; Terryn, H.; Andreatta, F.

    Aluminium alloys of the 7xxx series (Al-Zn-Mg-Cu) are susceptible to localized types of corrosion like pitting, intergranular corrosion and exfoliation corrosion. This represents a limitation for the application of these alloys in the aerospace components because localized corrosion might have a

  15. Tantalum-copper alloy and method for making (United States)

    Schmidt, Frederick A.; Verhoeven, John D.; Gibson, Edwin D.


    A tantalum-copper alloy can be made by preparing a consumable electrode consisting of an elongated copper billet containing at least two spaced apart tantalum rods extending longitudinally the length of the billet. The electrode is placed in a dc arc furnace and melted under conditions which co-melt the copper and tantalum to form the alloy.

  16. Structure of nanocomposites of Al–Fe alloys prepared by ...

    Indian Academy of Sciences (India)


    Abstract. Structures of Al-based nanocomposites of Al–Fe alloys prepared by mechanical alloying (MA) and subsequent annealing are compared with those obtained by rapid solidification processing (RSP). MA pro- duced only supersaturated solid solution of Fe in Al up to 10 at.% Fe, while for higher Fe content up to 20 at.

  17. Structural disordering of de-alloyed Pt bimetallic nanocatalysts

    DEFF Research Database (Denmark)

    Spanos, Ioannis; Dideriksen, Knud; Kirkensgaard, Jacob Judas Kain


    nanoparticles almost completely de-alloy during acid leaching, i.e. under reaction conditions in a fuel cell. To scrutinize the resulting particle structure after de-alloying we used pair distribution function (PDF) analysis and X-ray diffraction (XRD) gaining insight into the structural disorder and its...

  18. Structure and properties of V90Co10 membrane alloy (United States)

    Sipatov, Ivan; Pastukhov, Eduard; Fetisov, Andrey; Zvonarev, Sergey; Melchakov, Stanislav


    Alloys based on vanadium having bcc structure are considered as an alternative to palladium membrane alloys for hydrogen filtering. The membrane alloy (V90Co10) was studied by X-ray photoelectron spectroscopy, scanning electron and confocal microscopy. Gaseous impurities (oxygen, nitrogen, carbon, and hydrogen) in the membrane alloy was measured. The surface preparation method for the membrane alloy was developed, this makes possible to reduce roughness (Ra) down to 0.05 µm. It was established that in subsurface layer (˜10 nm) vanadium is in metallic form as well as 4+ and 2+ oxidation levels; while cobalt has only metallic form. Homogeneous distribution of elements in the bulk alloy was proved by chemical microanalysis. The value of hydrogen permeability of the V90Co10 membrane alloy was measured by non-stationary technique within the temperature and pressure ranges (623-723 K and 9-30 kPa, respectively). It was found that the hydrogen permeability of the V90Co10 membrane alloy is comparable with membranes made of metallic palladium.

  19. Helimagnetic structures in epitaxial Nd/Y superlattices and alloys

    DEFF Research Database (Denmark)

    Everitt, B.A.; Salamon, M.B.; Borchers, J.A.


    The complex magnetic structure of Nd exhibits a new magnetic phase when grown epitaxially, either as a stabilized double hexagonal close-packed alloy, or as part of a Nd/Y superlattice. In the alloy and in those superlattices with small Nd/Y ratios, the incommensurate b axis modulated structure e...

  20. Influence of alloying and secondary annealing on anneal hardening ...

    Indian Academy of Sciences (India)


    Abstract. This paper reports results of investigation carried out on sintered copper alloys (Cu, 8 at%; Zn,. Ni, Al and Cu–Au with 4 at%Au). The alloys were subjected to cold rolling (30, 50 and 70%) and annealed isochronally up to recrystallization temperature. Changes in hardness and electrical conductivity were fol-.

  1. Cobalt, nickel and chromium release from dental tools and alloys. (United States)

    Kettelarij, Jolinde A B; Lidén, Carola; Axén, Emmy; Julander, Anneli


    Cobalt-chromium alloys are used as casting alloys by dental technicians when producing dental prostheses and implants. Skin exposure and metal release from alloys and tools used by the dental technicians have not been studied previously. To study the release of cobalt, nickel and chromium from alloys and tools that come into contact with the skin of dental technicians. Cobalt and nickel release from tools and alloys was tested with the cobalt spot test and the dimethylglyoxime test for nickel. Also, the release of cobalt, nickel and chromium in artificial sweat (EN1811) at different time-points was assessed. Analysis was performed with inductively coupled plasma-mass spectrometry. Sixty-one tools were spot tested; 20% released nickel and 23% released cobalt. Twenty-one tools and five dental alloys were immersed in artificial sweat. All tools released cobalt, nickel and chromium. The ranges were 0.0047-820, 0.0051-10 and 0.010-160 µg/cm(2) /week for cobalt, nickel and chromium, respectively. All dental alloys released cobalt in artificial sweat, with a range of 0.0010-17 µg/cm(2) /week, and they also released nickel and chromium at low concentrations. Sensitizing metals are released from tools and alloys used by dental technicians. This may cause contact allergy and hand eczema. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  2. Interfacial properties of immiscible Co-Cu alloys

    DEFF Research Database (Denmark)

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


    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....


    African Journals Online (AJOL)


    1 SEPTEMBER 1983 NTUKOGU. 42. SULFURIC ACID CORROSION OF LOW Sb - Pb BATTERY ALLOYS by. T. O. Ntukogu. Mechanical Engineering Department. University of Nigeria, Nsukka. (Manuscript received February,1983). ABSTRACT. The corrosion properties of low Sb - Pb alloys developed for maintenance free ...

  4. Combined Corrosion and Wear of Aluminium Alloy 7075-T6

    NARCIS (Netherlands)

    Liu, Y.; Mol, J.M.C.; Janssen, G.C.A.M.


    The aluminium alloy 7075-T6 is widely used in engineering. In some applications, like slurry transport, corrosion and abrasion occur simultaneously, resulting in early material failure. In the present work, we investigated the combined effect of corrosion and wear on the aluminium alloy 7075-T6. We

  5. Grain refinement of AZ31 magnesium alloy by electromagnetic ...

    Indian Academy of Sciences (India)

    The effects of electromagnetic stirring and Al4C3 grain refiner on the grain refinement of semicontinuously cast AZ31 magnesium alloy were discussed in this investigation. The results indicate that electromagnetic stirring has an effective refining effect on the grain size of AZ31 magnesium alloy under the effect of Al4C3 ...

  6. Autocatalytic continuous precipitation in an Al-8 wt. % Mg alloy

    Energy Technology Data Exchange (ETDEWEB)

    Hamana, D.; Nebti, S.; Boutefnouchet, A.; Chekroud, S. (Research Unit of Materials Physics, Constantine Univ. (Algeria))


    The precipitation mechanism of a supersaturated solid solution of Al-8 wt.% Mg alloy is studied. An autocatalytic continuous reaction due to a heterogeneous nucleation and growth into grains, is observed in this alloy where usually only continuous precipitation can occur. It has been shown that preceding cold working and dynamic deformation, using ultrasonic vibration, have no influence on this heterogeneous precipitation. (orig.).

  7. In vitro cytotoxicity of metallic ions released from dental alloys

    NARCIS (Netherlands)

    Milheiro, A.; Nozaki, K.; Kleverlaan, C.J.; Muris, J.; Miura, H.; Feilzer, A.J.


    The cytotoxicity of a dental alloy depends on, but is not limited to, the extent of its corrosion behavior. Individual ions may have effects on cell viability that are different from metals interacting within the alloy structure. We aimed to investigate the cytotoxicity of individual metal ions in

  8. Gallium alloy films investigated for use as boundary lubricants (United States)


    Gallium alloyed with other low melting point metals has excellent lubricant properties of fluidity and low vapor pressure for high temperature or vacuum environments. The addition of other soft metals reduces the corrosivity and formation of undesirable alloys normally found with gallium.

  9. Effective and Environmentally Friendly Nickel Coating on the Magnesium Alloy

    Directory of Open Access Journals (Sweden)

    Ivana Škugor Rončević


    Full Text Available The low density and good mechanical properties make magnesium and its alloys attractive construction materials in the electronics, automotive, and aerospace industry, together with application in medicine due to their biocompatibility. Magnesium AZ91D alloy is an alloy with a high content of aluminum, whose mechanical properties overshadow the low corrosion resistance caused by the composition of the alloy and the existence of two phases: α magnesium matrix and β magnesium aluminum intermetallic compound. To improve the corrosion resistance, it is necessary to find an effective protection method for the alloy surface. Knowing and predicting electrochemical processes is an essential for the design and optimization of protective coatings on magnesium and its alloys. In this work, the formations of nickel protective coatings on the magnesium AZ91D alloy surface by electrodeposition and chemical deposition, are presented. For this purpose, environmentally friendly electrolytes were used. The corrosion resistance of the protected alloy was determined in chloride medium using appropriate electrochemical techniques. Characterization of the surface was performed with highly sophisticated surface-analytical methods.

  10. Ceramic coated Y1 magnesium alloy surfaces by microarc oxidation ...

    Indian Academy of Sciences (India)


    vibration load resistance, fine processing or machinability, little dimensional change, etc. Its highest advantage is sought in marine applications (Jiang et al 2004). Magne- sium alloy Y1 contains Al and Zn as alloying elements. Due to these elements, Y1 finds marine applications like side panels, floor plates, moldings, ship ...

  11. Property Criteria for Automotive Al-Mg-Si Sheet Alloys. (United States)

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


    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.

  12. Materials data handbook: Stainless steel alloy A-286 (United States)

    Muraca, R. F.; Whittick, J. S.


    A summary of the materials property information for stainless steel alloy A-286 is presented. The scope of the information includes physical and mechanical properties at cryogenic, ambient, and elevated temperatures. Information on material procurement, metallurgy of the alloy, corrosion, environmental effects, fabrication, and bonding is developed.

  13. Surface hardness behaviour of Ti–Al–Mo alloys

    Indian Academy of Sciences (India)


    Such a report is lacking in literature in this class of alloys. Keywords. ... Room temperature ductility is the most important impediment in the way of their applicability as high temperature structural material. Alloys with two phases (α2 and γ) have demon- strated an ... about the mechanical behaviour of the material (Zhang et.

  14. Development of new metallic alloys for biomedical applications. (United States)

    Niinomi, Mitsuo; Nakai, Masaaki; Hieda, Junko


    New low modulus β-type titanium alloys for biomedical applications are still currently being developed. Strong and enduring β-type titanium alloy with a low Young's modulus are being investigated. A low modulus has been proved to be effective in inhibiting bone atrophy, leading to good bone remodeling in a bone fracture model in the rabbit tibia. Very recently β-type titanium alloys with a self-tunable modulus have been proposed for the construction of removable implants. Nickel-free low modulus β-type titanium alloys showing shape memory and super elastic behavior are also currently being developed. Nickel-free stainless steel and cobalt-chromium alloys for biomedical applications are receiving attention as well. Newly developed zirconium-based alloys for biomedical applications are proving very interesting. Magnesium-based or iron-based biodegradable biomaterials are under development. Further, tantalum, and niobium and its alloys are being investigated for biomedical applications. The development of new metallic alloys for biomedical applications is described in this paper. Copyright © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  15. Ductile fracture surface morphology of amorphous metallic alloys

    NARCIS (Netherlands)

    Miskuf, J; Csach, Kornel; Ocelik, [No Value; Bengus, VZ; Tabachnikova, ED; Duhaj, P; Ocelik, Vaclav


    Ductile shear failure of hulk amorphous metallic alloys was studied using a fractographic is analysis. Although the mechanisms of shear deformation and fracture are appeared the same as in conventional amorphous ribbons, some new fractographic features are observed in bulk alloys. Geometric

  16. New weldable high strength aluminum alloy developed for cryogenic service (United States)


    Wrought aluminum alloy has improved low temperature notch toughness and weldability. This alloy can be mill-fabricated to plate and sheet without difficulty. Post-weld aging improves weld ductility and strength properties. A typical treatment is 8 hours at 225 deg F plus 16 hours at 300 deg F.

  17. New tungsten alloy has high strength at elevated temperatures (United States)


    Tungsten-hafnium-carbon alloy has tensile strengths of 88,200 psi at 3000 deg F and 62,500 psi at 3500 deg F. Possible industrial applications for this alloy would include electrical components such as switches and spark plugs, die materials for die casting steels, and heating elements.

  18. Corrosion protection of aluminum alloys in contact with other metals (United States)

    Kuster, C. A.


    Study establishes the quality of chemical and galvanized protection afforded by anodized and aldozided coatings applied to test panels of various aluminum alloys. The test panels, placed in firm contact with panels of titanium alloys, were subjected to salt spray tests and visually examined for corrosion effect.

  19. Characterization of zinc–nickel alloy electrodeposits obtained from ...

    Indian Academy of Sciences (India)

    Zinc alloy offers superior sacrificial protection to steel as the alloy dissolves more slowly than pure zinc. ... characterization of zinc-nickel electrodeposits obtained from sulphamate bath containing substituted aldehydes was carried out using hardness testing, X-ray diffraction, and corrosion resistance measurements.

  20. Strength and Ductility of Forged 1200 Aluminum Alloy Reinforced ...

    African Journals Online (AJOL)

    Strength and ductility responses of forged AA1200 aluminum alloy reinforced with steel particles have been studied. Steel particles of sizes 106, 181, 256, 362 and 512μm were separately added to the aluminum alloy to produced cylindrical shape samples, which were homogenized at 4200C for 10 hours, further processed ...

  1. Production and processing of Cu-Cr-Nb alloys (United States)

    Ellis, David L.; Michal, Gary M.; Orth, Norman W.


    A new Cu-based alloy possessing high strength, high conductivity, and good stability at elevated temperatures was recently produced. This paper details the melting of the master alloys, production of rapidly solidified ribbon, and processing of the ribbon to sheet by hot pressing and hot rolling.

  2. Textural and morphological studies on zinc–iron alloy electrodeposits

    Indian Academy of Sciences (India)

    Abstract. Zinc–iron alloy electrodeposits have industrial significance, since they provide better corrosion resistance and with improved mechanical properties when compared to pure zinc coatings. This is due to the unique phase structure of the alloy formed. But this deposition belongs to anomalous deposition, where the.

  3. Alloy design of ductile phosphoric iron: Ideas from archaeometallurgy

    Indian Academy of Sciences (India)


    Abstract. Alloy design criteria to produce ductile phosphoric irons have been proposed based on a detailed microstructural study of ancient Indian irons. The alloy design aims at avoiding phosphorus segregation to the grain boundaries by (a) soaking the phosphoric iron at high temperatures within the ferrite + austenite.

  4. Textural and morphological studies on zinc-iron alloy electrodeposits

    Indian Academy of Sciences (India)

    Zinc-iron alloy electrodeposits have industrial significance, since they provide better corrosion resistance and with improved mechanical properties when compared to pure zinc coatings. This is due to the unique phase structure of the alloy formed. But this deposition belongs to anomalous deposition, where the ...

  5. Reducing Stress-Corrosion Cracking in Bearing Alloys (United States)

    Paton, N. E.; Dennies, D. P.; Lumsden, I., J.b.


    Resistance to stress-corrosion cracking in some stainless-steel alloys increased by addition of small amounts of noble metals. 0.75 to 1.00 percent by weight of palladium or platinum added to alloy melt sufficient to improve properties of certain stainless steels so they could be used in manufacture of high-speed bearings.


    Directory of Open Access Journals (Sweden)

    A. Kalinichenko


    Full Text Available Application of nanomaterials for grain refining of metals and its allac is of great interest as it aimis achieveto higher physicalmechanical properties in finished parts. Analysis shows that to gain high effectiveness of nanoparticles it is important to provide proper input of these particles into alloying alloy. The aim of present research is study of initial nanoparticles structure on the base of titanium, boron, yttrium and carbon nanotubes as well as development of method to manufacture alloying alloys containing nanoparticles.Investigations of nanopowders phase compositions on the base of titanium, boron and yttrium have shown that active elements such as boron carbide, titanium carbide and nitride, yttrium oxide are base compounds of these nanopowders. Powder particles are formed by primary structural elements having mainly plate state (titanium and boron carbides and containing equiaxial inclusions with sizes of 5–200 nm. Chemical composition of specimens synthesized is uniform and contains 98.0 – 99.5% of main compound.Results of metal-protector and nanoparticles mixing have revealed that the increase of mixing duration from 2 to 6 hours assist to more uniform elements distribution through the pellet volume. Applying extrusion method specimens of alloying alloys have been produced and elements distribution in cross-section and longitudinal directions were determined.Analysis of research implemented has shown that distribution of active nanopowders in matrix is more uniform in extruded alloying alloys specimens compared to ones produced by methods of sintering or pressing of powder mixtures.

  7. On the coexistence of the magnetic phases in chromium alloys

    DEFF Research Database (Denmark)

    Lebech, Bente; Mikke, K.


    Detailed neutron diffraction investigations have been performed on Cr-Re alloys in order to explain the several observations in Cr alloys of the coexistence of a commensurable and an oscillatory magnetic phase. It is concluded that the individual magnetic phases probably occur in separate domains....

  8. Metal dusting: relationship between alloy composition and degradation rate

    NARCIS (Netherlands)

    Hermse, C.G.M.; Wortel, J.C. van


    The authors have identified a compositional relationship between several commercially available wrought alloys, focussing only on the iron, nickel, chromium and aluminium content. The degradation rate due to metal dusting varies with the surface condition of each alloy: a ground surface condition

  9. Fatigue in a heat treatable high silicon containing aluminium alloy (United States)

    González, J. A.; Talamantes-Silva, J.; Valtierra, S.; Colás, Rafael


    The use of cast aluminium alloys in automobiles contributes to reductions in weight and fuel consumption without impairing the safety for the occupants or the performance of the car. Most of the alloys used are heat treatable hypoeutectic Al-Si alloys, which have the drawback of exhibiting low wear resistance. So industry relies in wear resistant alloys, such as grey iron, for the liners of the combustion chambers in engine blocks, which increase the weight of the engine. Therefore, it is of interest to cast high silicon containing alloys into engine components that are able to resist wear while maintaining the mechanical properties required by the components. This work presents the result of the work carried out in a high silicon containing heat treatable aluminium alloy as it is subjected to high cycle fatigue. The alloy was prepared and cast in ingots designed to promote one dimensional solidification gradient to obtain samples to study the high cycle fatigue. The material was machined into hour-glass specimens that were tested at room temperature in a servohydraulic machine under load control following the stair case method. The results show that the resistance to fatigue depends on the microstructure of the sample, as the fatigue cracks originate in pores close to the surface of the sample and propagate through the eutectic aggregate. The results from this work are compared with those from previously obtained with hypoeutectic alloys.

  10. Additive Manufacturing of High-Entropy Alloys by Laser Processing

    NARCIS (Netherlands)

    Ocelik, V.; Janssen, Niels; Smith, Stefan; De Hosson, J. Th M.

    This contribution concentrates on the possibilities of additive manufacturing of high-entropy clad layers by laser processing. In particular, the effects of the laser surface processing parameters on the microstructure and hardness of high-entropy alloys (HEAs) were examined. AlCoCrFeNi alloys with

  11. Production of new titanium alloy for orthopedic implants

    Energy Technology Data Exchange (ETDEWEB)

    Taddei, E.B. [Instituto Tecnologico de Aeronautica (ITA), Centro Tecnico Aeroespacial, Sao Jose dos Campos-SP, 12228-904 (Brazil)]. E-mail:; Henriques, V.A.R. [AMR-DiviSao de Materiais-Instituto de Aeronautica e Espaco (IAE), Centro Tecnico Aeroespacial, Sao Jose dos Campos-SP, 12228-904 (Brazil); Silva, C.R.M. [AMR-DiviSao de Materiais-Instituto de Aeronautica e Espaco (IAE), Centro Tecnico Aeroespacial, Sao Jose dos Campos-SP, 12228-904 (Brazil); Cairo, C.A.A. [AMR-DiviSao de Materiais-Instituto de Aeronautica e Espaco (IAE), Centro Tecnico Aeroespacial, Sao Jose dos Campos-SP, 12228-904 (Brazil)


    The beta titanium alloys is one of the most promising groups of the titanium alloys. This fact is due to the good formability, mechanical properties and potential applications; moreover, these alloys present the highest level of mechanical, fatigue and corrosion resistance. The beta titanium alloys present the lowest elastic modulus, an interesting property for orthopedic implants. A {beta} alloy recently developed for this application is Ti-35Nb-7Zr-5Ta. In this work, the alloy was produced by powder metallurgy, unique available alternative for obtaining parts with porous structure (until 50% of porosity), that is one important characteristic for the osteointegration. The Ti-35Nb-7Zr-5Ta samples were manufactured by blended elemental method from a sequence of uniaxial and cold isostatic pressing with subsequent densification by sintering among 900 at 1700 deg. C, in vacuum. The objective of this work is the analysis of alloy microstructural evolution from the elemental powders dissolution under the increase of the sintering temperature. The alloy was characterized by scanning electron microscopy, X-ray diffraction and Vickers microhardness measurements. Density was measured by Archimedes method. The results show that a {beta}-homogeneous microstructure is obtained in the whole sample with the increase of sintering temperature. With the beginning of the {beta}-stabilizers (Nb and Ta) dissolution, at low sintering temperatures, there is the formation of an intermediary Widmanstaetten ({alpha}+{beta}) phase.

  12. Anisotropy of 2A66 Al-Li Alloy Sheet

    Directory of Open Access Journals (Sweden)

    ZHANG Xian-feng


    Full Text Available The anisotropy and microstructures during aging treatment for 2A66 Al-Li alloy were studied by Brinell hardness, tensile testing, optical microscope(OM, scanning electron microscope(SEM and transmission electron microscope (TEM. The main factors which influence the anisotropy of mechanical properties were discussed. The results indicate that, before 165℃ peak-aged, the anisotropy of the mechanical properties of the 2A66 Al-Li alloy decreases gradually with the extension of aging time. When the alloy is over-aged, the anisotropy of the alloy increases; the anisotropy of ductility is more serious than that of strength. The IPA values of σb, σ0.2 and δ of the alloy reach the lowest value at 3.0%, 3.0% and 12.2% respectively at the time of peak aging (64h, and the alloy is also obtained with good plasticity and axial tensile properties. σb, σ0.2 and δ of the alloy are 526.5, 448.9MPa, 10.1% respectively. Under different heat treatment conditions, the general behavior of the anisotropy of 2A66 Al-Li alloy is as follows: longitudinal (0° and transverse (90° have the highest strength, 45° direction is the lowest strength; 45° direction specimen has the highest elongation, vertical and horizontal direction has the minimum elongation.

  13. Thermal conductivity of Cu–4⋅ 5 Ti alloy

    Indian Academy of Sciences (India)

    The thermal conductivity (TC) of peak aged Cu–4.5 wt% Ti alloy was measured at different temperatures and studied its variation with temperature. It was found that TC increased with increasing temperature. Phonon and electronic components of thermal conductivity were computed from the results. The alloy exhibits an ...

  14. Giant magnetoresistance of electrodeposited Cu–Co–Ni alloy films

    Indian Academy of Sciences (India)

    Electrodeposition of CuCoNi alloys was performed in an acid–citrate medium. Nickel density parameter was varied in order to analyse its influence on the magnetoresistance. The structure and giant magneto- resistance (GMR) effect of CuCoNi alloys have been investigated. The maximum value for GMR ratio, at room ...

  15. Magnetic structures of holmium-lutetium alloys and superlattices

    DEFF Research Database (Denmark)

    Swaddling, P.P.; Cowley, R.A.; Ward, R.C.C.


    Alloys and superlattices of Ho and Lu have been grown using molecular beam epitaxy and their magnetic structures determined using neutron-scattering techniques. The 4f moments in the alloys form a helix at all compositions with the moments aligned in the basal plane perpendicular to the wave vect...

  16. Formation of alumina layers on iron-base alloys

    Energy Technology Data Exchange (ETDEWEB)

    Peters, J.; Grabke, H.J.


    The formation of Al/sub 2/O/sub 3/-layers has been studied for ferritic alloys Fe-6Al-M and austenitic alloys Fe-27 Ni-4 Al-M where M-Ti, Zr, V, Nb, W, B, Si... (concentration in wt%). One or more alloying elements M had been added and in some cases carbon. The oxidation was performed at 1000/sup 0/C in H/sub 2/O-H/sub 2/ mixtures at PO/sub 2/ = 10/sup -19/ bar. After 1/2 h oxidation the oxide layers were investigated by X-ray structures analysis, scanning electron microscopy and Auger electron spectroscopy (AES). The alloy Fe-6Al and most doped alloys form badly adherent layers, however, on alloys with additions of 0.1 to 1% Ti, Zr, V or Y the oxide layers are fine-grained and well-adherent. The Ti-doped ferritic alloys showed very protective layers, which is caused by the formation of a Ti(C, O)-layer beneath the ..cap alpha..-Al/sub 2/O/sub 3/. The presence of the oxicarbide induces nucleation and improves the adherence of ..cap alpha..-Al/sub 2/O/sub 3/, according to epitaxial relations between ferrite and oxicarbide and between oxicarbide and alumina. The favourable influence of Ti and Zr on the Al/sub 2/O/sub 3/ formation is also effective on the austenitic alloys.

  17. Controlled reactions between chromia and coating on alloy surface

    DEFF Research Database (Denmark)

    Linderoth, Søren


    An electrically conducting Sr-doped lanthanum chromite (LSC) coating has been produced by reacting a coating of fine particles of La oxide and Sr oxide with chromia formed as an external scale on a metallic alloy. In addition to the formation of LSC the coating also resulted in much reduced...... buckling of the underlying chromia layer compared with a non-coated alloy....

  18. Microstructural characterization of the γ-TiAl alloy samples ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 25; Issue 7. Microstructural characterization of the -TiAl alloy samples fabricated by direct laser fabrication rapid prototype technique. D Srivastava. Alloys and Steels Volume 25 ... Keywords. Titanium aluminide; microstructure; direct laser fabrication; rapid prototyping.

  19. Electrochemical and surface characterization of a nickel-titanium alloy

    NARCIS (Netherlands)

    Wever, Dirk; Veldhuizen, AG; de Vries, J; Busscher, HJ; Uges, DRA; van Horn, James


    For clinical implantation purposes of shape memory metals the nearly equiatomic nickel-titanium (NiTi) alloy is generally used. In this study, the corrosion properties and surface characteristics of this alloy were investigated and compared with two reference controls, AISI 316 LVM stainless steel


    Directory of Open Access Journals (Sweden)

    Jong-Hoon Lee


    Full Text Available The analysis of the electroslag remelting (ESR process schemes was carried out. For heat-resistant material on the basis of chromium chosen scheme crucible ESR with nonconsumable bifilar electrodes. Developed and manufactured laboratory plant for studying the processes of electroslag remelting crucible chromium-based alloys. Samples from chromium based alloy were obtained.