Simulation of Zr content in TiZrCuNi brazing filler metal for Ti6Al4V alloy

International Nuclear Information System (INIS)

Yue, Xishan; Xie, Zonghong; Jing, Yongjuan

2017-01-01

To optimize the Zr content in Ti-based filler metal, the covalent electron on the nearest atoms bond in unit cell (n_A"u"-"v) with Ti-based BCC structure was calculated, in which the brazing temperature was considered due to its influence on the lattice parameter. Based on EET theory (The Empirical Electron Theory for solid and molecules), n_A"u"-"v represents the strength of the unit cell with defined element composition and structure, which reflects the effect from solid solution strengthening on the strength of the unit cell. For Ti-Zr-15Cu-10Ni wt% filler metal, it kept constant as 0.3476 with Zr as 37.5 ∝ 45 wt% and decreased to 0.333 with Zr decreasing from 37.5 to 25 wt%. Finally, it increased up to 0.3406 with Zr as 2 ∝ 10 wt%. Thus, Ti-based filler metal with Zr content being 2 ∝ 10 wt% is suggested based on the simulation results. Moreover, the calculated covalent electron of n_A"u"-"v showed good agreement with the hardness of the joint by filler 37.5Zr and 10Zr. The composition of Ti-10Zr-15Cu-10Ni wt% was verified in this study with higher tensile strength of the brazing joint and uniform microstructure of the interface. (orig.)

Simulation of Zr content in TiZrCuNi brazing filler metal for Ti6Al4V alloy

Energy Technology Data Exchange (ETDEWEB)

Yue, Xishan [Northwestern Polytechnical University, School of Astronautics, Xi' an (China); AVIC Beijing Aeronautical Manufacturing Technology Research Institute, Aeronautical Key Laboratory for Welding and Joining Technology, Beijing (China); Xie, Zonghong [Northwestern Polytechnical University, School of Astronautics, Xi' an (China); Jing, Yongjuan [AVIC Beijing Aeronautical Manufacturing Technology Research Institute, Aeronautical Key Laboratory for Welding and Joining Technology, Beijing (China)

2017-07-15

To optimize the Zr content in Ti-based filler metal, the covalent electron on the nearest atoms bond in unit cell (n{sub A}{sup u-v}) with Ti-based BCC structure was calculated, in which the brazing temperature was considered due to its influence on the lattice parameter. Based on EET theory (The Empirical Electron Theory for solid and molecules), n{sub A}{sup u-v} represents the strength of the unit cell with defined element composition and structure, which reflects the effect from solid solution strengthening on the strength of the unit cell. For Ti-Zr-15Cu-10Ni wt% filler metal, it kept constant as 0.3476 with Zr as 37.5 ∝ 45 wt% and decreased to 0.333 with Zr decreasing from 37.5 to 25 wt%. Finally, it increased up to 0.3406 with Zr as 2 ∝ 10 wt%. Thus, Ti-based filler metal with Zr content being 2 ∝ 10 wt% is suggested based on the simulation results. Moreover, the calculated covalent electron of n{sub A}{sup u-v} showed good agreement with the hardness of the joint by filler 37.5Zr and 10Zr. The composition of Ti-10Zr-15Cu-10Ni wt% was verified in this study with higher tensile strength of the brazing joint and uniform microstructure of the interface. (orig.)

The crystallization of (NiCu)ZrTiAlSi glass/crystalline composite

International Nuclear Information System (INIS)

Czeppe, T.; Sypien, A.; Ochin, P.; Anastassova, S.

2007-01-01

Alloys of composition (Ni 1-x Cu x ) 60 Zr 18 Ti 13 A1 5 Si 4 were investigated in the form of ribbons and massive samples. The microstructure of the massive samples consists of dendritic crystals in the amorphous or nanocrystalline matrix. The amount of the amorphous phase is the lowest in the sample with the highest Cu content. The segregation in the liquid phase, leading to the local differences in density and the composition of the crystallizing dendrites in the samples crystallized in the copper mould was shown. The typical compositions of the multi-component crystals could be distinguished; one with the increased content of aluminum, the second with the high content of silicon and third, with the high content of (NiCu) and (ZrTi). The cubic phase Ni(Cu)Ti(Zr) with Cu and Zr dissolved could be identified. (Abstract Copyright [2007], Wiley Periodicals, Inc.)

Fracture toughness study of new Zr-based Be-bearing bulk metallic glasses

OpenAIRE

Kim, C. Paul; Suh, Jin-Yoo; Wiest, Aaron; Lind, Mary Laura; Conner, R. Dale; Johnson, William L.

2009-01-01

Three new compositional variants of the Zr–Ti–Be–LTM (late transition metal) family of metallic glasses are discussed. Thermal stability, ΔT = T_x−T_g, was increased from 82 °C for Zr_(41.2)Ti_(13.8)Cu_(12.5)Ni_(10)Be_(22.5) (Viterloy 1) to 141 °C for Zr_(44)Ti_(11)Cu_(20)Be_(25). It is found that fracture toughness is the most distinguishing parameter characterizing the alloys in contrast to other mechanical properties. Quaternary alloys consistently had fracture toughness values exceeding 8...

Bulk glass formation and crystallization in Zr54.5Cu20Al10Ni8Ti7.5 alloy

International Nuclear Information System (INIS)

Neogy, S.; Tewari, R.; Srivastava, D.; Dey, G.K.; Kumar, V.; Ranganathan, S.

2006-01-01

The present work was aimed at fabrication, characterization and crystallization of Zr 54.5 Cu 20 Al 10 Ni 8 Ti 7.5 bulk metallic glass. The glass forming alloy was made by arc melting and then subjected to copper mold casting into 3 mm diameter bulk glass rods. The as-cast microstructure was characterized by optical microscopy and transmission electron microscopy (TEM)

Mechanical properties and microstructure of commercial amorphous golf club heads made of Zr-Ti-Cu-Ni-Be bulk metallic glass

International Nuclear Information System (INIS)

Choi, Y.C.; Hong, S.I.

2007-01-01

Mechanical properties and microstructures of Zr 41.2 Ti 13.8 Cu 12.5 Ni 10 Be 22.5 (numbers indicate at.%) bulk metallic glass taken from commercial golf club heads were investigated at room temperature and 573 K. Transmission electron microscopy (TEM) and differential scanning calorimetry (DSC) indicate that the thin central section of the golf club head is amorphous and the outer rim of the head is crystallized. X-ray diffraction (XRD) analyses revealed the presence of Zr 2 Cu, ZrBe 2 , Cu 2 Ni and BeNi in the rim of the iron head. In the crystallized region, crystalline particles with the size of ∼1 μm were observed. At room temperature, amorphous sample (∼2100 MPa) revealed higher fracture stress than crystallized sample (∼1700 MPa). Crystallized sample fractured in the elastic region whereas the amorphous sample displayed some plasticity corresponding serrated flow before the fracture. The serrated flow region with some plasticity in the amorphous alloy results from strain hardening and repetitive shear band initiation and propagation. The crystallized alloy extracted from the thick part of the club fractured in the elastic region, at a much lower stress level than the amorphous, suggesting that relatively coarse crystal particles formed during cooling cause the brittle fracture. Scanning electron microscope observations revealed that the compressive fracture surface of the samples from the central thin section mainly consisted of vein-like structure, but the samples from the outer rim of the head showed mixture of vein-like structure and featureless brittle fracture morphology. At 573 K, both samples exhibited the decrease of strength and fractured in the elastic region. In this study, the effect of crystallization on the reliability and safety of golf club heads was also examined

Nonlinear elastic properties of bulk metallic glasses Zr52.5Ti5Cu17.9Ni14.6Al10 and Pd40Cu30Ni10P20

International Nuclear Information System (INIS)

Kobelev, N.P.; Kolyvanov, E.L.; Khonik, V.A.

2005-01-01

The influence of uniaxial compression on the propagation of ultrasonic vibrations in Zr 52.5 Ti 5 Cu 17.9 Ni 14.6 Al 10 and Pd 40 Cu 30 Ni 10 P 20 bulk metallic glasses produced by melt quenching at a rate of 100 K/s is investigated. Elastic deformation was realized by compression of the samples along their long axis up to strains of about 1 GPa. Deriving of major ratios used during the calculation of the third-order elastic moduli of the glasses is described in brief, the results of the calculations being provided. A qualitative agreement between the calculated results and available data on the influence of the uniform pressure on the sound wave propagation rate was obtained [ru

Corrosion behavior of oxide-covered Cu47Ti34Zr11Ni8 (Vitreloy 101) in chloride-containing solutions

International Nuclear Information System (INIS)

Baca, N.; Conner, R.D.; Garrett, S.J.

2014-01-01

Highlights: • Enrichment of Ti/Zr (as TiO 2 /ZrO 2 ) and depletion of Cu/Ni due to thermodynamically driven segregation. • Dominant corrosion mechanism is pitting. • Pit interiors were depleted of Ti and Zr due to equilibrium solubilization of oxide layer. • Corrosion can be explained by equilibrium and metal nobility arguments. - Abstract: The corrosion resistance of oxides that form in air on Vitreloy 101 (Cu 47 Ti 34 Zr 11 Ni 8 ) metallic glass ribbons in NaCl and HCl solutions was studied by scanning electron microscopy, X-ray photoelectron spectroscopy and potentiodynamic polarization. The air-exposed alloy was covered by a TiO 2 /ZrO 2 layer overlying a Cu-enriched region beneath. Ni was absent at the surface. Segregation of Ti and Zr was driven by exothermic oxide formation. Immersion in NaCl or HCl caused pitting corrosion by local Galvanic reactions that depleted less noble Ti, Zr and Ni from the pit interiors, leaving them rich in more noble Cu. Corrosion products containing Ti and Zr accumulated around the pit. Pits were most numerous in 1.0 M HCl due to TiO 2 (s)/Ti 3+ (aq) equilibrium that resulted in rapid solubilization of the oxide, creating local weaknesses and an increased rate of pit formation. On average, Ti preferentially dissolved from the oxide in accord with metal nobility arguments

Ni-free Zr-Cu-Al-Nb-Pd bulk metallic glasses with different Zr/Cu ratios for biomedical applications.

Science.gov (United States)

Huang, Lu; Yokoyama, Yoshihiko; Wu, Wei; Liaw, Peter K; Pang, Shujie; Inoue, Akihisa; Zhang, Tao; He, Wei

2012-08-01

Zr-based bulk metallic glasses (BMGs) possess attractive properties for prospective biomedical applications. The present study designs Ni-free Zr-Cu-Al-Nb-Pd BMGs and investigates their in vitro biocompatibility by studying mechanical properties, bio-corrosion resistance, and cellular responses. The Ti-6Al-4V alloy is used as a reference material. It is found that the Zr-based BMGs exhibit good mechanical properties, including high strengths above 1600 MPa, high hardness over 4700 MPa, and low elastic moduli of 85-90 GPa. The Zr-based BMGs are corrosion resistant in a simulated body environment, as revealed by wide passive regions, low passive current densities, and high pitting overpotentials. The formation of ZrO(2)-rich surface passive films of the Zr-based BMGs contributes to their high corrosion resistance, whereas their pitting corrosion in the phosphate buffered saline solution can be attributed to the sensitivity of the ZrO(2) films to the chloride ion. The general biosafety of the Zr-based BMGs is revealed by normal cell adhesions and cell morphologies. Moreover, the Zr/Cu content ratio in the alloy composition affects the biocompatibility of the Zr-based BMGs, by increasing their corrosion resistance and surface wettability with the increase of the Zr/Cu ratio. Effects of Zr/Cu ratios can be used to guide the future design of biocompatible Zr-based BMGs. Copyright © 2012 Wiley Periodicals, Inc.

Glass transition, crystallization kinetics and pressure effect on crystallization of ZrNbCuNiBe bulk metallic glass

DEFF Research Database (Denmark)

Xing, P.F.; Zhuang, Yanxin; Wang, W.H.

2002-01-01

The glass transition behavior and crystallization kinetics of Zr48Nb8Cu14Ni12Be18 bulk metallic glass have been investigated by differential scanning calorimetry and x-ray powder diffraction (XRD). The activation energies of both glass transition and crystallization events have been obtained using...... the Kissinger method. Results indicate that this glass crystallizes by a three-stage reaction: (1) phase separation and primary crystallization of glass, (2) formation of intermetallic compounds, and (3) decomposition of intermetallic compounds and crystallization of residual amorphous phase. The pressure...

Hypervelocity impact on Zr51Ti5Ni10Cu25Al9 bulk metallic glass

International Nuclear Information System (INIS)

Zheng, W.; Huang, Y.J.; Pang, B.J.; Shen, J.

2011-01-01

Highlights: → Hypervelocity impact experiments were performed on a bulk metallic glass. → Morphology of the bullet hole presents three different regions. → The post-impact samples keep glassy structure. → Mechanical properties of the post-impact samples were studied by nanoindentation. → Mechanical properties of the post-impact samples were discussed by free-volume model. - Abstract: In this study, the hypervelocity impact experiments were performed on Zr 51 Ti 5 Ni 10 Cu 25 Al 9 bulk metallic glass using a two-stage light gas gun. The morphologies of the bullet holes exhibit three different regions: melting area, vein-pattern area, and radiating core feature area, suggesting that various regions experience different stress states during the hypervelocity impact. For the post-impact samples, the nano-hardness increases and plastic deformability decreases both with the increase in the distance from the bullet hole and with the decrease in the impact velocity, which is discussed by means of spherical stress wave theory and free-volume model.

Investigating the atomic level influencing factors of glass forming ability in NiAl and CuZr metallic glasses

Energy Technology Data Exchange (ETDEWEB)

Sedighi, Sina; Kirk, Donald Walter; Singh, Chandra Veer, E-mail: chandraveer.singh@utoronto.ca; Thorpe, Steven John [Department of Materials Science and Engineering, University of Toronto, Room 140, 184 College Street, Toronto, Ontario M5S 3E4 (Canada)

2015-09-21

Bulk metallic glasses are a relatively new class of amorphous metal alloy which possess unique mechanical and magnetic properties. The specific concentrations and combinations of alloy elements needed to prevent crystallization during melt quenching remains poorly understood. A correlation between atomic properties that can explain some of the previously identified glass forming ability (GFA) anomalies of the NiAl and CuZr systems has been identified, with these findings likely extensible to other transition metal–transition metal and transition metal–metalloid (TM–M) alloy classes as a whole. In this work, molecular dynamics simulation methods are utilized to study thermodynamic, kinetic, and structural properties of equiatomic CuZr and NiAl metallic glasses in an attempt to further understand the underlying connections between glass forming ability, nature of atomic level bonding, short and medium range ordering, and the evolution of structure and relaxation properties in the disordered phase. The anomalous breakdown of the fragility parameter as a useful GFA indicator in TM–M alloy systems is addressed through an in-depth investigation of bulk stiffness properties and the evolution of (pseudo)Gruneisen parameters over the quench domain, with the efficacy of other common glass forming ability indicators similarly being analyzed through direct computation in respective CuZr and NiAl systems. Comparison of fractional liquid-crystal density differences in the two systems revealed 2-3 times higher values for the NiAl system, providing further support for its efficacy as a general purpose GFA indicator.

Structural relaxation and crystallisation of bulk metallic glasses Zr41Ti14Cu12.5Ni10-xBe22.5Fex (x = 0 or 2) studied by mechanical spectroscopy

International Nuclear Information System (INIS)

Wang, Q.; Pelletier, J.M.; Dong, Y.D.; Ji, Y.F.

2004-01-01

The measurements of the internal friction and dynamic shear modulus as well as differential scanning calorimetry have been performed in order to investigate the structural relaxation and crystallization of Zr 41 Ti 14 Cu 12.5 Ni 10-x Be 22.5 Fe x (x=0 or 2) bulk metallic glasses. It is found that the glass transition is retarded and the thermal stability of supercooled liquid is increased by the Fe addition. The experimental results are well analyzed using a physical model, which can characterize atomic mobility and mechanical response of disordered condensed materials

Improvement of bio-corrosion resistance for Ti42Zr40Si15Ta3 metallic glasses in simulated body fluid by annealing within supercooled liquid region.

Science.gov (United States)

Huang, C H; Lai, J J; Wei, T Y; Chen, Y H; Wang, X; Kuan, S Y; Huang, J C

2015-01-01

The effects of the nanocrystalline phases on the bio-corrosion behavior of highly bio-friendly Ti42Zr40Si15Ta3 metallic glasses in simulated body fluid were investigated, and the findings are compared with our previous observations from the Zr53Cu30Ni9Al8 metallic glasses. The Ti42Zr40Si15Ta3 metallic glasses were annealed at temperatures above the glass transition temperature, Tg, with different time periods to result in different degrees of α-Ti nano-phases in the amorphous matrix. The nanocrystallized Ti42Zr40Si15Ta3 metallic glasses containing corrosion resistant α-Ti phases exhibited more promising bio-corrosion resistance, due to the superior pitting resistance. This is distinctly different from the previous case of the Zr53Cu30Ni9Al8 metallic glasses with the reactive Zr2Cu phases inducing serious galvanic corrosion and lower bio-corrosion resistance. Thus, whether the fully amorphous or partially crystallized metallic glass would exhibit better bio-corrosion resistance, the answer would depend on the crystallized phase nature. Copyright © 2015 Elsevier B.V. All rights reserved.

Zr-(Cu,Ag)-Al bulk metallic glasses

International Nuclear Information System (INIS)

Jiang, Q.K.; Wang, X.D.; Nie, X.P.; Zhang, G.Q.; Ma, H.; Fecht, H.-J.; Bendnarcik, J.; Franz, H.; Liu, Y.G.; Cao, Q.P.; Jiang, J.Z.

2008-01-01

In this paper, we report the formation of a series Zr-(Cu,Ag)-Al bulk metallic glasses (BMGs) with diameters at least 20 mm and demonstrate the formation of about 25 g amorphous metallic ingots in a wide Zr-(Cu,Ag)-Al composition range using a conventional arc-melting machine. The origin of high glass-forming ability (GFA) of the Zr-(Cu,Ag)-Al alloy system has been investigated from the structural, thermodynamic and kinetic points of view. The high GFA of the Zr-(Cu,Ag)-Al system is attributed to denser local atomic packing and the smaller difference in Gibbs free energy between amorphous and crystalline phases. The thermal, mechanical and corrosion properties, as well as elastic constants for the newly developed Zr-(Cu,Ag)-Al BMGs, are also presented. These newly developed Ni-free Zr-(Cu,Ag)-Al BMGs exhibit excellent combined properties: strong GFA, high strength, high compressive plasticity, cheap and non-toxic raw materials and biocompatible property, as compared with other BMGs, leading to their potential industrial applications

Crystallization of Cu60Ti20Zr20 metallic glass with and without pressure

DEFF Research Database (Denmark)

Jiang, Jianzhong; Yang, B.; Saksl, K.

2003-01-01

Structural stability of a Cu60Ti20Zr20 metallic glass under-pressure up to 4.5 GPa was investigated by x-ray diffraction. The sample exhibited a supercooled liquid region of 33 K and a ratio of the glass-transition temperature to the liquidus temperature of 0.63. The glass crystallized in two......, structure crystalline phase with a spacing group P6(3)/mmc (194) and lattice parameters a = 5.105 Angstrom and c = 8.231 Angstrom. Both crystallization temperatures increased with pressure having a slope of 19 K/GPa. The increase of the first crystallization temperature with increasing pressure in the glass...... can be explained by the suppression of atomic mobility. No significant structural change was detected in the Cu60Ti20Zr20 glass annealed,in vacuum at 697 K for I h as compared to the as-prepared sample from x-ray diffraction. measurements....

The kinetic glass transition of the Zr46.75Ti8.25Cu7.5Ni10Be27.5 bulk metallic glass former-supercooled liquids on a long time scale

International Nuclear Information System (INIS)

Busch, R.; Johnson, W.L.

1998-01-01

Viscosity and enthalpy relaxation from the amorphous state into the supercooled liquid state was investigated in the bulk metallic glass forming Zr 46.75 Ti 8.25 Cu 7.5 Ni 10 Be 27.5 alloy below the calorimetric glass transition. At different temperatures, the viscosities relax into states that obey the same Vogel endash Fulcher endash Tammann relation as the data obtained at higher temperatures in the supercooled liquid. Enthalpy recovery experiments after relaxation in the same temperature range show that the enthalpy of the material reaches values that also corresponds to the supercooled liquid state. The glass relaxes into a metastable supercooled liquid state, if it is observed on a long time scale. Equilibration is possible far below the calorimetric glass transition and very likely even below the isentropic temperature. copyright 1998 American Institute of Physics

Glass-forming ability and stability of ternary Ni-early transition metal (Ti/Zr/Hf) alloys

Energy Technology Data Exchange (ETDEWEB)

Basu, Joysurya [Department of Metallurgy, Indian Institute of Science, Bangalore 560 012 (India); Ranganathan, S. [Department of Metallurgy, Indian Institute of Science, Bangalore 560 012 (India)]. E-mail: rangu@met.iisc.ernet.in

2006-08-15

Four Ni-bearing Ti, Zr and Hf ternary alloys of nominal composition Zr{sub 41.5}Ti{sub 41.5}Ni{sub 17}, Zr{sub 25}Ti{sub 25}Ni{sub 50}, Zr{sub 41.5}Hf{sub 41.5}Ni{sub 17} and Ti{sub 41.5}Hf{sub 41.5}Ni{sub 17} were rapidly solidified in order to produce ribbons. The Zr-Ti-Ni and Ti-Hf-Ni alloys become amorphous, whereas the Zr-Hf-Ni alloy shows precipitation of a cubic phase. The devitrification of all three alloys was followed and the relative tendency to form nanoquasicrystals and cF96 phases analysed. The relative glass-forming ability of the alloys can be explained by taking into account their atomic size difference. Addition of Ni often leads to quasicrystallisation or quasicrystal-related phases. This can be explained by the atomic radius and heat of mixing of the constituent elements. The phases precipitated at the initial stages of crystallisation indicate the possible presence of Frank-Kasper polyhedral structure in the amorphous alloys. Structural analysis reveals that the Laves and the anti-Laves phases have the same polyhedral structural unit, which is similar to the structural characteristics of glass.

Deformation-strengthening during rolling Cu60Zr20Ti20 bulk metallic glass

DEFF Research Database (Denmark)

Cao, Q.P.; Li, J.F.; Hu, Yuyan

2007-01-01

Mechanical strength evolutions during rolling the Cu60Zr20Ti20 bulk metallic glass (BMG) at room temperature (RT) and cryogenic temperature (CT) have been investigated by measuring the microhardness. The hardness slightly increases during the initial rolling stage as a result of the gradually...

Structural study of Zr-based metallic glasses

International Nuclear Information System (INIS)

Matsubara, E.; Ichitsubo, T.; Saida, J.; Kohara, S.; Ohsumi, H.

2007-01-01

Structures of Zr 70 Ni 20 Al 10 , Zr 70 Cu 20 Al 10 , Zr 70 Cu 30 and Zr 70 Ni 30 amorphous alloys were analyzed by high-energy X-ray diffraction. The relatively stable Zr 2 Cu amorphous alloy shows a local atom arrangement different from the Zr 2 Cu crystalline phase. By contrast, the less stable Zr 70 Ni 30 amorphous alloy has a structure similar to Zr 2 Ni. In the Zr 70 Cu 20 Al 10 metallic glass, Zr-Al nearest neighbor pairs are introduced in the amorphous structure. In the Zr 70 Ni 20 Al 10 metallic glass, the strong correlation between Zr-Ni pairs is drastically modified by the formation of Zr-Al pairs. The presence of Zr-Al pairs in the ternary alloys suppresses the crystallization and stabilizes the glassy state

Superconductivity and spin fluctuations in M-Zr metallic glasses (M = Cu, Ni, Co, and Fe)

International Nuclear Information System (INIS)

Altounian, Z.; Strom-Olsen, J.O.

1983-01-01

The superconducting transition temperature, upper critical field, and magnetic susceptibility have been measured in four binary metallic glass systems: Cu-Zr, Ni-Zr, Co-Zr, and Fe-Zr. For each alloy system, a full and continuous range of Zr-rich compositions accessible by melt spinning has been examined. For Cu-Zr, the range is 0.75>x>0.30; for Ni-Zr, 0.80>x>0.30; for Co-Zr, 0.80>x>0.48, and for Fe-Zr, 0.80>x>0.55 (x being the concentration of Zr in at. %). The results show clearly the influence of spin fluctuations in reducing the superconducting transition temperature. The data have been successfully analyzed using a modified form of the McMillan equation together with expressions for the Stoner enhanced magnetic susceptibility and the Ginsburg-Landau-Abrikosov-Gor'kov expression for the upper critical field

Glass forming ability and mechanical properties of the NiZrTiSi amorphous alloys modified with Al, Cu and Nb additions

International Nuclear Information System (INIS)

Czeppe, Tomasz; Ochin, Patrick; Sypien, Anna

2007-01-01

The composition of the amorphous alloy Ni 59 Zr 20 Ti 16 Si 5 was modified with 2-9 at.% additions of Cu, Al and Nb. The ribbons and the bars 2.7 mm in diameter were prepared by melt spinning and injection casting from the alloys of the compositions: Ni 56 Zr 18 Ti 16 Si 5 Al 3 Cu 2 , Ni 56 Zr 18 Ti 13 Al 6 Si 5 Cu 2 , Ni 56 Zr 16 Ti 12 Nb 9 Al 3 Cu 2 Si 2 and Ni 56 Zr 16 Ti 12 Nb 6 Al 6 Cu 2 Si 2 . All ribbons were amorphous up to the resolution of the X-ray diffraction and conventional transmission electron microscopy, however rods were partially crystalline. Increase of Al content lowered and Nb content slightly increased crystallization start temperature T x and glass transition temperature T g . The influence of composition changes on the overcooled liquid range ΔT was more complicated. The increase of Nb and decrease of Ti and Zr content led to the remarkable increase of the liquidus temperature T l . As a result GFA calculated as T g /T l was lowered to the values about 0.63 for 6 and 9 at.% Nb addition. The activation energies for primary crystallization in alloy with 6 at.% Al and 6 at.% of Nb, were determined. The changes of tensile test strength and microhardness with Al and Nb additions showed hardening effect caused by Nb additions and increase in fracture strength with increasing Al content

Mechanically driven phase separation and corresponding microhardness change in Cu60Zr20Ti20 bulk metallic glass

DEFF Research Database (Denmark)

Cao, Q.P.; Li, J.F.; Zhou, Y.H.

2005-01-01

Rolling deformation of bulk Cu60Zr20Ti20 metallic glass has been performed at cryogenic temperature. The specimens exhibit excellent ductility, and are rolled up to 97% reduction in thickness without fracture. Crystallization is suppressed during the deformation, however, phase separation is obse...... is observed in the glassy matrix when the thickness reduction exceeds 89%. Once the phase separation occurs, the microhardness of the specimen increases drastically, indicating the existence of work hardening by severe plastic deformation of the metallic glass.......Rolling deformation of bulk Cu60Zr20Ti20 metallic glass has been performed at cryogenic temperature. The specimens exhibit excellent ductility, and are rolled up to 97% reduction in thickness without fracture. Crystallization is suppressed during the deformation, however, phase separation...

Structural study of Zr-based metallic glasses

Energy Technology Data Exchange (ETDEWEB)

Matsubara, E. [Department of Materials Science and Engineering, Kyoto University, Kyoto 606-8501 (Japan)]. E-mail: e.matsubara@materials.mbox.media.kyoto-u.ac.jp; Ichitsubo, T. [Department of Materials Science and Engineering, Kyoto University, Kyoto 606-8501 (Japan); Saida, J. [Center of Interdisciplinary Research, Tohoku University, Sendai 980-8578 (Japan); Kohara, S. [JASRI, SPring-8, Sayo-gun, Hyogo 679-5198 (Japan); Ohsumi, H. [JASRI, SPring-8, Sayo-gun, Hyogo 679-5198 (Japan)

2007-05-31

Structures of Zr{sub 70}Ni{sub 20}Al{sub 10}, Zr{sub 70}Cu{sub 20}Al{sub 10}, Zr{sub 70}Cu{sub 30} and Zr{sub 70}Ni{sub 30} amorphous alloys were analyzed by high-energy X-ray diffraction. The relatively stable Zr{sub 2}Cu amorphous alloy shows a local atom arrangement different from the Zr{sub 2}Cu crystalline phase. By contrast, the less stable Zr{sub 70}Ni{sub 30} amorphous alloy has a structure similar to Zr{sub 2}Ni. In the Zr{sub 70}Cu{sub 20}Al{sub 10} metallic glass, Zr-Al nearest neighbor pairs are introduced in the amorphous structure. In the Zr{sub 70}Ni{sub 20}Al{sub 10} metallic glass, the strong correlation between Zr-Ni pairs is drastically modified by the formation of Zr-Al pairs. The presence of Zr-Al pairs in the ternary alloys suppresses the crystallization and stabilizes the glassy state.

Pressure effect on crystallization kinetics in Zr46.8Ti8.2Cu7.5Ni10Be27.5 bulk glass

DEFF Research Database (Denmark)

Jiang, Jianzhong; Gerward, Leif; Xu, Y.S.

2002-01-01

Crystallization kinetics of a Zr46.8Ti8.2Cu7.5Ni10Be27.5 bulk glass in the supercooled liquid region have been investigated by performing in situ high-temperature and high-pressure x-ray diffraction measurements using synchrotron radiation. A pressure-time-temperature-transformation diagram......, describing the onset of crystallization as a function of time during isothermal annealing under pressure, is presented. Different pressure dependences of crystallization kinetics in the temperature range for the glass have been observed and further be explained by a model of competing processes...

Cu-Zr-Ag bulk metallic glasses based on Cu8Zr5 icosahedron

International Nuclear Information System (INIS)

Xia Junhai; Qiang Jianbing; Wang Yingmin; Wang Qing; Dong Chuang

2007-01-01

Based on the cluster line criterion, the Ag addition into the Cu 8 Zr 5 cluster composition is investigated for the search of ternary Cu-Zr-Ag bulk metallic glasses with high glass forming abilities. Two initial binary compositions Cu 0.618 Zr 0.382 and Cu 0.64 Zr 0.36 are selected. The former one corresponds to a deep eutectic point; it is also the composition of the Cu 8 Zr 5 icosahedron, which is derived from the Cu 8 Zr 3 structure. The latter one, which can be regarded as the Cu 8 Zr 5 cluster plus a glue atom Cu, is the best glass-forming composition in the Cu-Zr binary system. Two composition lines (Cu 0.618 Zr 0.382 ) 1-x Ag x and (Cu 0.64 Zr 0.36 ) 1-x Ag x are thus constructed in the Cu-Zr-Ag system by linking these two compositions with the third constitute Ag. A series of Cu-Zr-Ag bulk metallic glasses are found with 2-8 at.% Ag contents in both composition lines. The optimum composition (Cu 0.618 Zr 0.382 ) 0.92 Ag 0.08 within the searched region with the highest T g /T l = 0.633, is located along the cluster line (Cu 0.618 Zr 0.382 ) 1-x Ag x , where the deep eutectic Cu 0.618 Zr 0.382 exactly corresponds to the dense packing cluster Cu 8 Zr 5 . The alloying mechanism is discussed in the light of atomic size and electron concentration factors

Second amorphous-to-crystalline phase transformation in Cu(60)Ti(20)Zr(20) bulk metallic glass.

Science.gov (United States)

Cao, Q P; Li, J F; Zhang, P N; Horsewell, A; Jiang, J Z; Zhou, Y H

2007-06-20

The second amorphous-to-crystalline phase transformation in Cu(60)Ti(20)Zr(20) bulk metallic glass was investigated by differential scanning calorimetry and x-ray diffractometry. The difference of the Gibbs free energies between the amorphous phase and the crystalline products during the transformation is estimated to be about 2.46 kJ mol(-1) at 753 K, much smaller than the 61 kJ mol(-1) obtained assuming that it is a polymorphic transformation. It was revealed that the phase transformation occurs through a eutectic crystallization of Cu(51)Zr(14) and Cu(2)TiZr, having an effective activation energy of the order of 400 kJ mol(-1). The average Avrami exponent n is about 2.0, indicating that the crystallization is diffusion controlled.

Nanoindentation studies on Cu-Ti-Zr-Ni-Si-Sn bulk metallic glasses

International Nuclear Information System (INIS)

Mukhopadhyay, N.K.; Belger, A.; Paufler, P.; Kim, D.H.

2007-01-01

In the present investigation, Cu 47 Ti 33 Ni 6 Sn 2 Si 1 (numbers indicate at.%) bulk metallic glass (BMG), fabricated by injection casting has been used for indentation experiments. Microindentation and nanoindentation tests were conducted to study the indentation responses of this material. The nanohardness and the Young's modulus were calculated following the standard procedure in literature. Around the indent, shear bands can be clearly observed under scanning electron microscopy examination. Atomic-force microscopy shows the pile of the material in a step-wise manner. The thinned sample near the indent shows the evolution of nanocrystals (∼20-30 nm) by transmission electron microscopy. During nanoindentation (in single- and multi-indent mode) experiments, the load-displacement P-h curves show displacement bursts, which are also known as pop-ins or serrations. The total displacement during indentation can be accounted for by sum total effect of the individual displacement of all the displacement-bursts observed in the P-h curve. Thus the plastic deformation of this glassy material appears to proceed in a discrete manner unlike ductile metallic alloys

Relation between calculated Lennard-Jones potential and thermal stability of Cu-based bulk metallic glasses

International Nuclear Information System (INIS)

Lin, T.; Bian, X.F.; Jiang, J.

2006-01-01

Two metallic bulk glasses, Cu 60 Zr 30 Ti 10 and Cu 47 Ti 33 Zr 11 Ni 8 Si 1 , with a diameter of 3 mm were prepared by copper mold casting method. Dilatometric measurement was carried out on the two glassy alloys to obtain information about the average nearest-neighbour distance r 0 and the effective depth of pair potential V 0 . By assuming a Lennard-Jones potential, r 0 and V 0 were calculated to be 0.28 nm and 0.16 eV for Cu 60 Zr 30 Ti 10 and 0.27 nm and 0.13 eV for Cu 47 Ti 33 Zr 11 Ni 8 Si 1 , respectively. It was found that the glassy alloy Cu 60 Zr 30 Ti 10 was more stable than Cu 47 Ti 33 Zr 11 Ni 8 Si 1 against heating from both experiment and calculation

Interphase Constituent of Laminated Composites Ti46Zr26Cu17Ni11

Directory of Open Access Journals (Sweden)

XU Bingtong

2017-10-01

Full Text Available Thermal analysis of the Ti46Zr26Cu17Ni11 amorphous ribbon prepared by melt spinning was conducted by using DSC. Accordingly the amorphous alloy was treated by vacuum heat treatment at 693 K (Tg, 753 K (Tg-Tx1 and 813 K (> Tx1 for different time to analyze the crystallization behavior. Taking Ti46Zr26Cu17Ni11 amorphous alloy, TA2 and pure Al as raw materials, laminated composites were fabricated by Gleeble-3500 thermal simulator at 873 K, 10 MPa and 8 h. The phase composition, precipitation order and properties of interface layers were investigated by SEM, TEM, micro hardness tester, combined thermodynamics and element diffusion theory. The results indicate that the glass transition temperature Tg of Ti46Zr26Cu17Ni11 amorphous is 720 K and the initial crystallization temperature Tx1 is 788 K. The I phase is crystallized from the amorphous at first, followed by a ternary or quaternary Laves phase and a TiNi phase precipited. After hot pressing, the interface between pure Al and crystallization layer is divided into two parts, which are Al3Ni with small thickness and Al3(Ti0.6Zr0.4 with fine grain and uniform microstructure. The interfaces are straight and there are no defects, with a thickness ratio of about 6.5:1 compared with interface layer between pure Ti with Al. The hardness of Al3(Ti0.6Zr0.4 and Al3Ti are 564.2HV and 579.8HV respectively. The plasticity of Al3(Ti0.6Zr0.4 layer is better.

Atomic structure of Zr{sub 41.2}Ti{sub 13.8}Cu{sub 12.5}Ni{sub 10}Be{sub 22.5} bulk metallic glass alloy

Energy Technology Data Exchange (ETDEWEB)

Hui, X. [State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China)], E-mail: huixd01@hotmail.com; Fang, H.Z.; Chen, G.L. [State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China); Shang, S.L.; Wang, Y. [Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA 16802 (United States); Qin, J.Y. [Key Laboratory of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University - Southern Campus, Jinan 250061 (China); Liu, Z.K. [Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA 16802 (United States)

2009-01-15

Ab initio molecular dynamics (AIMD) calculations were performed on the atomic configuration of Zr{sub 41.2}Ti{sub 13.8}Cu{sub 12.5}Ni{sub 10}Be{sub 22.5} bulk metallic glass. The local structures were characterized in terms of structure factors (SF), pair correlation functions (PCF), coordinate numbers, bond pairs and Voronoi polyhedra. The glass transition temperature, generalized PCF and SF predicated by AIMD are in good agreement with the experimental data. Icosahedral short-range orders (ISRO) are found to be the most dominant, in view of the presence of the majority of bond pairs with 1551, 1541 and 1431, and Voronoi polyhedra with <0,3,6,1>, <0,2,8,1>, <0,0,12,0> and <0,2,8,4>. Icosahedral medium range orders (IMROs) are formed from icosahedra via the linkage of vertex-, edge-, face- and intercross-shared atoms. The glass structure on the nanometer scale is accumulated by polyhedra through an efficient packing mode. It is suggested that the extraordinary glass-forming ability of this alloy is essentially attributable to the formation of ISRO and IMRO, and the dense packing of atoms.

Ti-based bulk metallic glass with high cold workability at room temperature

International Nuclear Information System (INIS)

Park, J.M.; Park, J.S.; Kim, J.H.; Lee, M.H.; Kim, D.H.; Kim, W.T.

2005-01-01

The cold workability of Ti-based bulk metallic glasses (BMGs) have been investigated. Ti 45 Zr 16 Be 20 Cu 10 Ni 9 BMG with a large compressive plastic strain of 4.7% shows a high cold workability, i.e. total reduction ratio of 50% by cold rolling at room temperature. The multiple shear bands formed during rolling are effective in enhancing the plasticity. The cold rolled Ti 45 Zr 16 Be 20 Cu 10 Ni 9 BMG (reduction ratio: 30%) exhibits a large plastic strain of ∝14%. (orig.)

Enthalpy of mixing of liquid Ni-Zr and Cu-Ni-Zr alloys

International Nuclear Information System (INIS)

Witusiewicz, V.T.; Sommer, F.

2000-01-01

Since the Al-Cu-Ni-Zr system is a basis for the production of bulk amorphous materials by rapid solidification techniques from the liquid state, it is of great scientific interest to determine the partial and the integral thermodynamic functions of liquid and undercooled liquid alloys. Such data, as was pointed out previously, are important in order to understand their extremely good glass-forming ability in multicomponent metallic systems as well as for processing improvements. In order to measure the thermodynamic properties of the Al-Cu-Ni-Zr quaternary, it is necessary to have reliable thermochemical data for its constituent canaries and ternaries first. In a series of articles, the authors have reported in detail the thermodynamic properties of liquid Al-Cu, Al-Ni, Cu-Ni, Cu-Zr, Al-Zr, Al-Cu-Ni, and Al-Cu-Zr alloys. This article deals with the direct calorimetric measurements of the partial and the integral enthalpies of mixing of liquid Ni-Zr and Cu-Ni-Zr alloys and the heat capacity of liquid Ni 26 Zr 74 . In a subsequent article, the authors will present similar data for the liquid ternary Al-Ni-Zr and for the liquid quaternary Al-Cu-Ni-Zr alloys

Second amorphous-to-crystalline phase transformation in Cu60Ti20Zr20 bulk metallic glass

DEFF Research Database (Denmark)

Cao, Q.P.; Li, J.F.; Zhang, P.N.

2007-01-01

The second amorphous-to-crystalline phase transformation in Cu60Ti20Zr20 bulk metallic glass was investigated by differential scanning calorimetry and x-ray diffractometry. The difference of the Gibbs free energies between the amorphous phase and the crystalline products during the transformation...

Glass formation and crystallization of Zr53Cu21Al10Ni8Ti8 alloy

International Nuclear Information System (INIS)

Neogy, S.; Tewari, R.; Srivastava, D.; Dey, G.K.; Banerjee, S.; Vaibhaw, K.; Ranganathan, S.

2010-01-01

In the present study, transmission electron microscopy techniques, like micro-diffraction, high resolution and fluctuation microscopy, have been employed to carry out detailed investigation of as-solidified and crystallized microstructures of the Zr 53 Cu 21 Al 10 Ni 8 Ti 8 alloy synthesized using melt spinning, suction casting and copper mould casting techniques. Samples produced by copper mould casting technique showed partially crystalline microstructure whereas the other techniques resulted in complete amorphous microstructures. High-resolution microscopy established that the dendrites of the big cube phase in partially crystalline glass grew by atomistic ledges. The other crystalline bct Zr 2 Ni phase, present in partially crystalline glass and also in all the crystallized microstructures, showed various types of internal faults depending upon the crystallite size. Fluctuation microscopy established that oxygen plays a major role in determining the degree of medium range order in glassy phases. In addition, variation in oxygen content changed the crystallization behaviour of glasses from a single to multiple events

Deformation behaviors of Cu29Zr32Ti15Al5Ni19 high entropy bulk metallic glass during nanoindentation

Science.gov (United States)

Fang, Qihong; Yi, Ming; Li, Jia; Liu, Bin; Huang, Zaiwang

2018-06-01

The deformation behaviors of Cu29Zr32Ti15Al5Ni19 high entropy bulk metallic glass (HE-BMG) during the nanoindentation are presented via the large-scale molecular dynamics (MD) simulations. The indentation tests are carried out using spherical rigid indenter to investigate the microstructural evolution on the mechanical properties of HE-BMGs in terms of shear strain, indentation force, and surface morphology as well as radial distribution function (RDF). Based on the Hertzian fitting the load-displacement curve, HE-BMG Cu29Zr32Ti15Al5Ni19 has the Young's modulus of 93.1 GPa and hardness of 8.8 GPa. The indentation force requiring for the continual increasing contacted area between the indenter and the substrate goes up with the increasing of indentation depth. In addition, the symmetrical distribution of atomic displacement reveals the isotropic of HE-BMG after the indentation treatment. In the deformation region, the Al element would lead to the serious fluctuation in the first peak of RDF, which is much stronger than the other elements. The severe distortion from the atomic size difference maybe reduce the activation energy to the occurrence of shear deformation in HE-BMG, leading to the transition from brittle to ductile observed by the whole sliding of the local atom group. Through the indentation load-displacement curves at various temperatures, the softening of HE-BMG at high temperatures is in qualitative agreement with the experimental findings. Moreover, this effective strategy is used to accelerate the discovery of excellent mechanical properties of HE-BMGs by means of MD simulation, as well as understand the fundamental nanoindentation response of HE-BMGs.

Evaluation of Ni-free Zr–Cu–Fe–Al bulk metallic glass for biomedical implant applications

Energy Technology Data Exchange (ETDEWEB)

Sun, Ying-Sui [Institute of Oral Biology, National Yang-Ming University, Taipei, Taiwan (China); Zhang, Wei [School of Materials Science and Engineering, Dalian University of Technology, Dalian (China); Kai, Wu [Institute of Materials Engineering, National Taiwan Ocean University, Keelung, Taiwan (China); Liaw, Peter K. [Department of Materials Science and Engineering, The University of Tennessee, Knoxville, TN (United States); Huang, Her-Hsiung, E-mail: hhhuang@ym.edu.tw [Institute of Oral Biology, National Yang-Ming University, Taipei, Taiwan (China); Department of Dentistry, National Yang-Ming University, Taipei, Taiwan (China); Department of Dentistry, Taipei City Hospital, Taipei, Taiwan (China); Department of Stomatology, Taipei Veterans General Hospital, Taipei, Taiwan (China)

2014-02-15

Highlights: ► A Zr{sub 62.5}Cu{sub 22.5}Fe{sub 5}Al{sub 10} bulk metallic glass (BMG) with 50 GPa elastic modulus was used. ► This Ni-free Zr-based BMG had lower metal ion release rate than the commercial Ti. ► This Ni-free Zr-based BMG had better proteins adsorption than the commercial Ti. ► This Ni-free Zr-based BMG has a high potential for biomedical implant applications. -- Abstract: This study was conducted to investigate the surface characteristics, including the chemical composition, metal ion release, protein adsorption, and cell adhesion, of a Ni-free Zr-based (Zr{sub 62.5}Cu{sub 22.5}Fe{sub 5}Al{sub 10}) bulk metallic glass (BMG) with low elastic modulus for biomedical implant applications. X-ray photoelectron spectroscopy was used to identify the surface chemical composition and the protein (albumin and fibronectin) adsorption of the specimen. The metal ions released from the specimen in simulated blood plasma and artificial saliva solutions were measured using an inductively coupled plasma-mass spectrometer. The cell adhesion, in terms of the morphology, focal adhesion complex, and skeletal arrangement, of human bone marrow mesenchymal stem cells was evaluated using scanning electron microscope observations and immunofluorescent staining. For comparison purposes, the above-mentioned tests were also carried out on the widely used biomedical metal, Ti. The results showed that the main component on the outermost surface of the amorphous Zr{sub 62.5}Cu{sub 22.5}Fe{sub 5}Al{sub 10} BMG was ZrO{sub 2} with small amounts of Cu, Al, and Fe oxides. The released metal ions from Zr{sub 62.5}Cu{sub 22.5}Fe{sub 5}Al{sub 10} BMG were well below the critical concentrations that cause negative biological effects. The Zr{sub 62.5}Cu{sub 22.5}Fe{sub 5}Al{sub 10} BMG had a greater adsorption capacity for albumin and fibronectin than that of commercial biomedical Ti. The Zr{sub 62.5}Cu{sub 22.5}Fe{sub 5}Al{sub 10} BMG surface showed an attached cell number similar

The local structure nature for a Ti-based bulk metallic glass

International Nuclear Information System (INIS)

Chen, Yiqiang; Huang, Yongjiang; Fan, Hongbo; Wang, Dongjun; Shen, Jun

2013-01-01

Highlights: ► The directional bonds in TiZrNiCuBe bulk metallic glass are primarily comprised of Be-Ni and Be-Cu bonds. ► A coefficient η could be extracted from Raman scattering to characterize the glass forming ability. ► The weak directional bonds dependent on Be could increase the localized electrons, facilitating the glass forming ability. - Abstract: In the present work, the local atomic structures of a Be-containing Ti-based bulk metallic glass (BMG) have been characterized using electron spectrum for chemical analysis and Raman scattering, including directional bonds and medium range order. It might suggest that a coefficient could be extracted from Raman scattering to characterize the glass forming ability (GFA), which could be employed to interpret the enhanced GFA by Be addition of Ti-based BMG. Additionally, compared with the crystallized sample, the glassy sample exhibits larger average bond length and larger content of local bond distortion using Raman scattering.

Microstructures and tribological properties of laser cladded Ti-based metallic glass composite coatings

International Nuclear Information System (INIS)

Lan, Xiaodong; Wu, Hong; Liu, Yong; Zhang, Weidong; Li, Ruidi; Chen, Shiqi; Zai, Xiongfei; Hu, Te

2016-01-01

Metallic glass composite coatings Ti 45 Cu 41 Ni 9 Zr 5 and Ti 45 Cu 41 Ni 6 Zr 5 Sn 3 (at.%) on a Ti-30Nb-5Ta-7Zr (wt.%) (TNTZ) alloy were prepared by laser cladding. The microstructures of the coatings were characterized by means of X-ray diffractometry (XRD), scanning electron microscopy (SEM) equipped with energy dispersive X-ray analyzer (EDXA), and transmission electron microscopy (TEM). Results indicated that the coatings have an amorphous structure embedded with a few nanocrystalline phases and dendrites. A partial substitution of Ni by Sn can improve the glass forming ability of Ti-base metallic glass system, and induce the formation of nano-sized Ni 2 SnTi phase during the cyclic laser heating. The tribological behavior of both the substrate and the coatings was investigated in detail. A significant improvement in both the hardness and the wear resistance of the coatings was achieved with the addition of Sn. The relationship between the wear resistance and the microstructures of the coatings was discussed. - Highlights: •Ti-based metallic glass composite coatings were prepared by laser cladding. •The wear resistance is greatly improved by laser cladding of composite coatings. •Substitution of Ni by Sn increases GFA and wear resistance of the coatings. •A good balance of crystalline/amorphous phases improves the wear resistance. •Adhesive wear serves as the dominant wear mechanism of the composite coatings.

Non-isothermal crystallization kinetics and fragility of (Cu46Zr47Al7)97Ti3 bulk metallic glass investigated by differential scanning calorimetry

International Nuclear Information System (INIS)

Zhu, Man; Li, Junjie; Yao, Lijuan; Jian, Zengyun; Chang, Fang’e; Yang, Gencang

2013-01-01

Highlights: • Non-isothermal crystallization kinetics of (Cu 46 Zr 47 Al 7 ) 97 Ti 3 BMGs was studied. • Two-stage of crystallization process is confirmed by DSC. • The nucleation process is difficult than growth process during crystallization. • The second crystallization process is the most sensitive to heating rate. • Kinetic fragility index is evaluated suggesting it is an intermediate glass. - Abstract: In this paper, bulk metallic glasses with the composition of (Cu 46 Zr 47 Al 7 ) 97 Ti 3 were prepared by copper mold casting technique. X-ray diffraction (XRD) and differential scanning calorimetry (DSC) were used to investigate its structure and non-isothermal crystallization kinetics. DSC traces revealed that it undergoes two-stage crystallization. The activation energies corresponding to the characteristic temperatures have been calculated, and the results reveal that the as-cast alloys have a good thermal stability in thermodynamics. Based on Kissinger equation, the activation energies for glass transition, the first and second crystallization processes were obtained as 485 ± 16 kJ/mol, 331 ± 7 kJ/mol and 210 ± 3 kJ/mol, respectively, suggesting that the nucleation process is more difficult than the grain growth process. The fitting curves using Lasocka's empirical relation show that the influence of the heating rate for crystallization is larger than glass transition. Furthermore, the kinetic fragility for (Cu 46 Zr 47 Al 7 ) 97 Ti 3 bulk metallic glasses is evaluated. Depending on the fragility index, (Cu 46 Zr 47 Al 7 ) 97 Ti 3 bulk metallic glasses should be considered as “intermediate glasses”

Change of quasilattice constant during amorphous-to-quasicrystalline phase transformation in Zr65Al7.5Ni10Cu7.5Ag10 metallic glass

DEFF Research Database (Denmark)

Jiang, Jianzhong; Rasmussen, A.R.; Jensen, C.H.

2002-01-01

The amorphous-to-quasicrystalline phase transformation in a Zr65Al7.5Ni10Cu7.5Ag10 metallic glass has been investigated by monitoring the quasilattice constant and the composition of quasicrystalline particles in the samples annealed in vacuum at 663 K for various times. It is found that the quas......The amorphous-to-quasicrystalline phase transformation in a Zr65Al7.5Ni10Cu7.5Ag10 metallic glass has been investigated by monitoring the quasilattice constant and the composition of quasicrystalline particles in the samples annealed in vacuum at 663 K for various times. It is found......Cu7.5Ag10 metallic glass is a nonpolymorphous reaction....

Biocompatible Ni-free Zr-based bulk metallic glasses with high-Zr-content: compositional optimization for potential biomedical applications.

Science.gov (United States)

Hua, Nengbin; Huang, Lu; Chen, Wenzhe; He, Wei; Zhang, Tao

2014-11-01

The present study designs and prepares Ni-free Zr60+xTi2.5Al10Fe12.5-xCu10Ag5 (at.%, x=0, 2.5, 5) bulk metallic glasses (BMGs) by copper mold casting for potential biomedical application. The effects of Zr content on the in vitro biocompatibility of the Zr-based BMGs are evaluated by investigating mechanical properties, bio-corrosion behavior, and cellular responses. It is found that increasing the content of Zr is favorable for the mechanical compatibility with a combination of low Young's modulus, large plasticity, and high notch toughness. Electrochemical measurements demonstrate that the Zr-based BMGs are corrosion resistant in a phosphate buffered saline solution. The bio-corrosion resistance of BMGs is improved with the increase in Zr content, which is attributed to the enrichment in Zr and decrease in Al concentration in the surface passive film of alloys. Regular cell responses of mouse MC3T3-E1 cells, including cell adhesion and proliferation, are observed on the Zr-Ti-Al-Fe-Cu-Ag BMGs, which reveals their general biosafety. The high-Zr-based BMGs exhibit a higher cell proliferation activity in comparison with that of pure Zr and Ti-6Al-4V alloy. The effects of Zr content on the in vitro biocompatibility can be used to guide the future design of biocompatible Zr-based BMGs. Copyright © 2014 Elsevier B.V. All rights reserved.

Molecular dynamics study of the ternary Cu50Ti25Zr25 bulk glass forming alloy

Directory of Open Access Journals (Sweden)

Celtek M.

2011-05-01

Full Text Available The structure and thermodynamic properties of a ternary Cu50Ti25Zr25 metallic glass forming alloy in solid-liquid to glass phases were studied using molecular dynamics (MD method based on tight-binding (TB potentials. An atomic description of the melting, glass formation and crystallization process has been analyzed using different heating and cooling rates. The computed Glass Forming Ability (GFA parameters are in good agreement with experimental data. The structure analysis of the Cu50Ti25Zr25 based on molecular dynamics simulation will be also presented and compared with available MD results. We have also discussed the crystallization transition with two different interatomic potentials used in this work

Hierarchical surface patterning of Ni- and Be-free Ti- and Zr-based bulk metallic glasses by thermoplastic net-shaping

Energy Technology Data Exchange (ETDEWEB)

Sarac, Baran, E-mail: b.sarac@ifw-dresden.de [IFW Dresden, Institute for Complex Materials, Helmholtzstrasse 20, D-01069 Dresden (Germany); Erich Schmid Institute of Materials Science, Austrian Academy of Sciences (ÖAW), Jahnstrasse 12, A-8700 Leoben (Austria); Bera, Supriya [IFW Dresden, Institute for Complex Materials, Helmholtzstrasse 20, D-01069 Dresden (Germany); Balakin, Sascha [IFW Dresden, Institute for Complex Materials, Helmholtzstrasse 20, D-01069 Dresden (Germany); ETH Zurich, Department of Materials, Metal physics und Technology, Vladimir-Prelog-Weg 4, HCI J 492, 8093 Zürich (Switzerland); Stoica, Mihai [IFW Dresden, Institute for Complex Materials, Helmholtzstrasse 20, D-01069 Dresden (Germany); Politehnica University of Timisoara, P-ta Victoriei 2, RO-300006 Timisoara (Romania); Fraunhofer Institute for Ceramic Technologies and Systems IKTS, Winterbergstrasse 28, 01277, Dresden (Germany); Calin, Mariana, E-mail: m.calin@ifw-dresden.de [IFW Dresden, Institute for Complex Materials, Helmholtzstrasse 20, D-01069 Dresden (Germany); Eckert, Jürgen [Erich Schmid Institute of Materials Science, Austrian Academy of Sciences (ÖAW), Jahnstrasse 12, A-8700 Leoben (Austria); Department Materials Physics, Montanuniversität Leoben, Jahnstrasse 12, A-8700 Leoben (Austria)

2017-04-01

In order to establish a strong cell-material interaction, the surface topography of the implant material plays an important role. This contribution aims to analyze the formation kinetics of nickel and beryllium-free Ti- and Zr-based Bulk Metallic Glasses (BMGs) with potential biomedical applications. The surface patterning of the BMGs is achieved by thermoplastic net-shaping (TPN) into anisotropically etched cavities of silicon chips. The forming kinetics of the BMG alloys is assessed by thermal and mechanical measurements to determine the most suitable processing temperature and time, and load applied. Array of pyramidal micropatterns with a tip resolution down to 50 nm is achievable for the Zr-BMG, where the generated hierarchical features are crucial for surface functionalization, acting as topographic cues for cell attachment. The unique processability and intrinsic properties of this new class of amorphous alloys make them competitive with the conventional biomaterials. - Highlights: • Micro to nano-scale hierarchical surface patterns achieved by TPN of BMGs • Ni- and Be-free Zr-/Ti-BMGs with different GFA compared in terms of flow kinetics • Correlation between filling depths of Zr- and Ti-BMGs best described by formability • Multi-scale hierarchical patterning envisaged to facilitate BMG-cell interaction.

Crystallization of Zr₂Pd_xCu_1-x and Zr₂Ni_xCu_1-x Metallic Glass

Energy Technology Data Exchange (ETDEWEB)

Xu, Min [Iowa State Univ., Ames, IA (United States)

2008-01-01

One interesting aspect of rretallic glasses is the numerous instances of the deviation of the phase selection from the amorphous state to thermodynamically stable phases during the crystallization process. Their devitrification pathways allow us to study the relationship between the original amorphous structure and their crystalline counter parts. Among the various factors of phase selections, size and electronic effects have been most extensively studied. Elucidating the phase selection process of a glassy alloy will be helpful to fill in the puzzle of the changes from disordered to ordered structures. In this thesis, Two model Zr₂Pd_xCu_1-x and Zr₂Ni_xCu_1-x (x = 0, 0.25, 0.5, 0.75 and 1) glassy systems were investigated since: (1) All of the samples can be made into a homogenous metallic glass; (2) The atomic radii differ from Pd to Cu is by 11%, while Ni has nearly the identical atomic size compare to Cu. Moreover, Pd and Ni differ by only one valence electron from Cu. Thus, these systems are ideal to test the idea of the effects of electronic structure and size factors; (3) The small number of components in these pseudo binary systems readily lend themselves to theoretical modeling. Using high temperature X-ray diffraction (HTXRD) and thermal analysis, topological, size, electronic, bond and chemical distribution factors on crystallization selections in Zr₂Pd_xCu_1-x and Zr₂Ni_xCu_1-x metallic glass have been explored. All Zr₂Pd_xCu_1-x compositions share the same Cu11b phase with different pathways of meta-stable, icosahedral quasicrystalline phase (i-phase), and C16 phase formations. The quasicrystal phase formation is topologically related to the increasing icosahedral short range order (SRO) with Pd content in Zr₂Pd_xCu_1-x system. Meta-stable C16 phase is competitive with

Improvement of the thermoplastic formability of Zr65Cu17.5Ni10Al7.5 bulk metallic glass by minor addition of Erbium

International Nuclear Information System (INIS)

Hu, Q.; Zeng, X.R.; Fu, M.W.; Chen, S.S.; Jiang, J.

2016-01-01

The softness of Zr 65 Cu 17.5 Ni 10 Al 7.5 bulk metallic glass (BMG) in the super-cooled liquid range (SCLR) is obviously improved by minor addition of 2% Er, which makes (Zr 65 Cu 17.5 Ni 10 Al 7.5 ) 98 Er 2 (Zr65Er2) to be a very formable Be-free Zr-based BMG. It is found the lower glass transition temperature of Zr65Er2 has an important contribution to the improvement of formability, which is contrary to the general understanding that the larger fragility and wider super-cooled liquid region (SCLR) are the major reasons for better thermoplastic formability. This finding is well explained by using the linear simplification of the SCLR in Angell plot. Zr65Er2 also has lower crystallization temperature and melting temperature, which is believed to be related to the formation of short-range ordering with lower transition energy rather than the composition shift to near eutectic. The above results help understand the effect of minor addition of rare-earth to the formability of Zr-based bulk metallic glasses.

Time-temperature-transformation diagram of Zr-based Zr-Al-Cu-Ni metallic glasses

International Nuclear Information System (INIS)

Goh, T.T.; Li, Y.; Ng, S.C.

1996-01-01

The critical cooling rates R c for glass formation in four Zr-based Zr-Al-Cu-Ni alloys were determined using techniques developed by Uhlmann based on theories of homogeneous nucleation, crystal growth and transformation kinetics. It involves the construction of a time-temperature-transformation curve which requires the knowledge of the viscosity-temperature curve of the alloys. Two types of viscosity-temperature expressions, namely Andrade expression and Doolittle expression, were used to model the viscosity of the Zr-based alloys and the choice of the viscosity-temperature expression which gives the best estimate of the calculated time-temperature-transformation curve is discussed. (author)

Microstructures and tribological properties of laser cladded Ti-based metallic glass composite coatings

Energy Technology Data Exchange (ETDEWEB)

Lan, Xiaodong; Wu, Hong, E-mail: wuhong927@126.com; Liu, Yong, E-mail: yonliu@csu.edu.cn; Zhang, Weidong; Li, Ruidi; Chen, Shiqi; Zai, Xiongfei; Hu, Te

2016-10-15

Metallic glass composite coatings Ti{sub 45}Cu{sub 41}Ni{sub 9}Zr{sub 5} and Ti{sub 45}Cu{sub 41}Ni{sub 6}Zr{sub 5}Sn{sub 3} (at.%) on a Ti-30Nb-5Ta-7Zr (wt.%) (TNTZ) alloy were prepared by laser cladding. The microstructures of the coatings were characterized by means of X-ray diffractometry (XRD), scanning electron microscopy (SEM) equipped with energy dispersive X-ray analyzer (EDXA), and transmission electron microscopy (TEM). Results indicated that the coatings have an amorphous structure embedded with a few nanocrystalline phases and dendrites. A partial substitution of Ni by Sn can improve the glass forming ability of Ti-base metallic glass system, and induce the formation of nano-sized Ni{sub 2}SnTi phase during the cyclic laser heating. The tribological behavior of both the substrate and the coatings was investigated in detail. A significant improvement in both the hardness and the wear resistance of the coatings was achieved with the addition of Sn. The relationship between the wear resistance and the microstructures of the coatings was discussed. - Highlights: •Ti-based metallic glass composite coatings were prepared by laser cladding. •The wear resistance is greatly improved by laser cladding of composite coatings. •Substitution of Ni by Sn increases GFA and wear resistance of the coatings. •A good balance of crystalline/amorphous phases improves the wear resistance. •Adhesive wear serves as the dominant wear mechanism of the composite coatings.

Friction welding of bulk metallic glasses to different ones

International Nuclear Information System (INIS)

Shoji, Takuo; Kawamura, Yoshihito; Ohno, Yasuhide

2004-01-01

For application of bulk metallic glasses (BMGs) as industrial materials, it is necessary to establish the metallurgical bonding technology. The BMGs exhibit high-strain-rate superplasticity in the supercooled liquid state. It has been reported that bulk metallic glasses were successfully welded together by friction, pulse-current, explosion and electron-beam methods. In this study, friction welding of the BMGs to different ones were tried for Pd 40 Ni 40 P 20 , Pd 40 Cu 30 P 20 Ni 10 , Zr 55 Cu 30 Al 10 Ni 5 and Zr 41 Be 23 Ti 14 Cu 12 Ni 10 BMGs. Successful welding was obtained in the combinations of the Pd 40 Ni 40 P 20 and Pd 40 Cu 30 P 20 Ni 10 BMGs, and the Zr 55 Cu 30 Al 10 Ni 5 and Zr 41 Be 23 Ti 14 Cu 12 Ni 10 ones. No crystallization was observed and no visible defect was recognized in the interface. The joining strength of the welded BMGs was the same as that of the parent BMG or more. BMGs seem to be successfully welded to the different ones with a difference below about 50 K in glass transition temperature

Stability and electronic structure of Zr-based ternary metallic glasses and relevant compounds

International Nuclear Information System (INIS)

Hasegawa, M.; Soda, K.; Sato, H.; Suzuki, T.; Taketomi, T.; Takeuchi, T.; Kato, H.; Mizutani, U.

2007-01-01

The electronic structure of the Zr-based metallic glasses has been investigated by theoretical and experimental approaches. One approach is band calculations of the Zr 2 Ni (Zr 66.7 Ni 33.3 ) compound to investigate the electronic structure of the Zr 66.7 Ni 33.3 metallic glass (ΔT x = 0 K) of which the local atomic structure is similar to that of the Zr 2 Ni compound. The other is photoemission spectroscopy of the Zr 50 Cu 35 Al 15 bulk metallic glass (BMG) (ΔT x = 69 K). Here ΔT x = T x - T g where T x and T g are crystallization and glass transition temperature, respectively. Both results and previous ones on the Zr 55 Cu 30 Ni 5 Al 10 BMG indicate that there is a pseudogap at the Fermi level in the electronic structure of these Zr-based metallic glasses, independent of the value of the ΔT x . This implies that the pseudogap at the Fermi level is one of the factors that stabilize the glass phase of Zr-based metallic glasses

Crystallization behaviors of Zr-Ti-Cu-Ni-Be BMG sheet fabricated by squeeze-casting method and its micro-scaled forming

Energy Technology Data Exchange (ETDEWEB)

Jeong, H.G. [Advanced Fusion Process Group, Production Technology R and D Department, Korea Institute of Industrial Technology, Incheon (Korea, Republic of); Lee, J.B., E-mail: ljb01@kitech.re.kr [Advanced Fusion Process Group, Production Technology R and D Department, Korea Institute of Industrial Technology, Incheon (Korea, Republic of)

2012-09-25

Highlights: Black-Right-Pointing-Pointer Compressibility and formability of Zr{sub 62.6}Ti{sub 11}Cu{sub 13.2}Ni{sub 9.8}Be{sub 3.4} BMG sheets increases with an increase in forging temperature and pressure. Black-Right-Pointing-Pointer Crystallization in the alloy BMG sheet began to occur during micro-scaled forming. Black-Right-Pointing-Pointer The volume fraction of crystalline phase increases as the forging temperature and pressure increase. - Abstract: We report the micro-scaled forming of Zr{sub 62.6}Ti{sub 11}Cu{sub 13.2}Ni{sub 9.8}Be{sub 3.4} bulk metallic glass (BMG) as a function of the forging pressure within super-cooled liquid region (SLR), and its effects on the transition to crystallization. The morphology after micro-scaled forming was examined by using a field emission scanning electron microscope (FE-SEM). Thermal behavior of the forged samples was analyzed by using a differential scanning calorimeter (DSC). It was found for perfect forming of the alloy BMG sheets that the temperature of 703 K and the pressure of 20 MPa are required in the present study. The compressibility and the volume fraction of crystalline phase increase with an increase of the forging pressure and temperature, and they are sensitive to temperature more than pressure within SLR.

Strong composition-dependence on glass-forming ability in Ni-(Ti,Zr)-Si pseudo-ternary alloys

International Nuclear Information System (INIS)

Yang, H.; Wang, J.Q.; Li, Y.

2006-01-01

The glass formation in Ni-(Ti,Zr)-Si pseudo-ternary alloys was studied. For suction casting, by carefully adjusting the alloy composition and studying the microstructure changes, the best glass-forming alloy with a 2 mm diameter is pinpointed in a narrow composition region of 57.5-58.5 at.% Ni, 36.5-38.5 at.% (Ti + Zr) and 5-5.5 at.% Si. The main competing crystalline phases, identified by XRD and SEM, were Ni 10 (Zr,Ti) 7 , Ni(Ti,Zr) and an unidentified Si-containing phase. Our results indicate a clear need for monitoring the microstructure change in the cross section of the ingots to locate the best glass-forming alloys

Internal friction behaviours in Zr57Al10Ni12.4Cu15.6Nb5 bulk metallic glass

International Nuclear Information System (INIS)

Zhang Bo; Zu Fangqiu; Zhen Kang; Shui Jiapeng; Wen Ping

2002-01-01

The internal friction patterns of Zr 57 Al 10 Ni 12.4 Cu 15.6 Nb 5 bulk metallic glass (BMG) were investigated with different frequencies and heating rates. An internal friction peak with extremely large magnitude is observed in the internal friction curves as a function of temperature (Q -1 -T curves). The internal friction peak was fitted by an equation Q -1 =AX(T)/η, where A is a constant, X(T) is the fraction of the glass/supercooled liquid and the viscosity η obeys the Vogel-Fulcher-Tammann relation. We confirm that the internal friction peak originates from both of the glass transition and crystallization. The anomalous behaviours of the peak suggest that Zr 57 Al 10 Ni 12.4 Cu 15.6 Nb 5 BMG has a wide supercooled liquid region and the magnitude of the peak can be used to judge the glass forming ability (GFA) of the glass forming alloys. In addition, the internal friction technique proved to be a new powerful tool for studying structural relaxation and phase transition as well as the GFA of BMG. (author)

Potentiodynamic polarization studies of bulk amorphous alloy Zr57Cu15.4Ni12.6Al10Nb5 and Zr59Cu20Ni8Al10Ti3 in aqueous HNO3 media

International Nuclear Information System (INIS)

Sharma, Poonam; Dhawan, Anil; Jayraj, J.; Kamachi Mudali, U.

2013-01-01

The potentiodynamic polarization studies were carried out on Zr based bulk amorphous alloy Zr 57 Cu 15.4 Ni 12.6 Al 10 Nb 5 and Zr 59 Cu 20 Ni 8 Al 10 Ti 3 in solutions of 1 M, 6 M and 11.5 M HNO 3 aqueous media at room temperature. As received specimens of Zr 57 Cu 15.4 Ni 12.6 Al 10 Nb 5 (5 mm diameter rod) and Zr 59 Cu 20 Ni 8 Al 10 Ti 3 (3 mm diameter rod) were polished with SiC paper before testing them for potentiodynamic polarization studies. The amorphous nature of the specimens was checked by X-ray diffraction. The bulk amorphous alloy Zr 59 Cu 20 Ni 8 Al 10 Ti 3 shows the better corrosion resistance than Zr 57 Cu 15.4 Ni 12.6 Al 10 Nb 5 alloy in the aqueous HNO 3 media as the value of the corrosion current density (I corr ) for Zr 57 Cu 15.4 Ni 12.6 Al 10 Nb 5 alloy were found to be more than Zr 59 Cu 20 Ni 8 Al 10 Ti 3 alloy in aqueous HNO 3 media. The improved corrosion resistance of Zr 59 Cu 20 Ni 8 Al 10 Ti 3 alloy is possibly due to the presence of Ti and formation of TiO 2 during anodic oxidation. Both Zr based bulk amorphous alloys shows wider passive range at lower concentration of nitric acid and the passive region gets narrowed down with the increase in concentration. A comparison of data obtained from both the Zr-based bulk amorphous alloys is made and results are discussed in the paper. (author)

Biocompatible Ni-free Zr-based bulk metallic glasses with high-Zr-content: Compositional optimization for potential biomedical applications

Energy Technology Data Exchange (ETDEWEB)

Hua, Nengbin, E-mail: flower1982cn@126.com [Department of Materials Science and Engineering, Fujian University of Technology, 350118 Fuzhou (China); Department of Materials Science and Engineering, Fuzhou University, 350116 Fuzhou (China); Huang, Lu [Department of Materials Science and Engineering, The University of Tennessee, Knoxville, TN 37996-2100 (United States); Chen, Wenzhe [Department of Materials Science and Engineering, Fujian University of Technology, 350118 Fuzhou (China); Department of Materials Science and Engineering, Fuzhou University, 350116 Fuzhou (China); He, Wei [Department of Materials Science and Engineering, The University of Tennessee, Knoxville, TN 37996-2100 (United States); Department of Mechanical, Aerospace and Biomedical Engineering, The University of Tennessee, Knoxville, TN 37996-2200 (United States); Zhang, Tao [Key Laboratory of Aerospace Materials and Performance (Ministry of Education), School of Materials Science and Engineering, Beihang University, 100191 Beijing (China)

2014-11-01

The present study designs and prepares Ni-free Zr{sub 60+x}Ti{sub 2.5}Al{sub 10}Fe{sub 12.5−x}Cu{sub 10}Ag{sub 5} (at.%, x = 0, 2.5, 5) bulk metallic glasses (BMGs) by copper mold casting for potential biomedical application. The effects of Zr content on the in vitro biocompatibility of the Zr-based BMGs are evaluated by investigating mechanical properties, bio-corrosion behavior, and cellular responses. It is found that increasing the content of Zr is favorable for the mechanical compatibility with a combination of low Young's modulus, large plasticity, and high notch toughness. Electrochemical measurements demonstrate that the Zr-based BMGs are corrosion resistant in a phosphate buffered saline solution. The bio-corrosion resistance of BMGs is improved with the increase in Zr content, which is attributed to the enrichment in Zr and decrease in Al concentration in the surface passive film of alloys. Regular cell responses of mouse MC3T3-E1 cells, including cell adhesion and proliferation, are observed on the Zr–Ti–Al–Fe–Cu–Ag BMGs, which reveals their general biosafety. The high-Zr-based BMGs exhibit a higher cell proliferation activity in comparison with that of pure Zr and Ti-6Al-4V alloy. The effects of Zr content on the in vitro biocompatibility can be used to guide the future design of biocompatible Zr-based BMGs. - Highlights: • Ni-free Zr{sub 60+x}Ti{sub 2.5}Al{sub 10}Fe{sub 12.5−x}Cu{sub 10}Ag{sub 5} (at.%, x = 0, 2.5, 5) BMGs were fabricated. • Plasticity and notch toughness of BMGs are enhanced by high-Zr-content. • The high-Zr-based BMGs exhibit excellent bio-corrosion resistance in PBS solution. • The biosafety of BMGs is revealed by regular cell adhesion and proliferation. • High-Zr-bearing BMGs are favorable for potential applications as biomaterials.

Alloying effect on the room temperature creep characteristics of a Ti-Zr-Be bulk metallic glass

Science.gov (United States)

Gong, Pan; Wang, Sibo; Li, Fangwei; Wang, Xinyun

2018-02-01

The effect of alloying elements (e.g. Fe, Al, and Ni) on the room temperature creep behavior of a lightweight Ti41Zr25Be34 bulk metallic glass (BMG) was investigated via nanoindentation tests. The generalized Kelvin model was adopted to describe the creep curves. The strain rate sensitivity m has been derived as a measure of the creep resistance. The compliance spectrum and retardation spectrum were also derived. The results show that the creep resistance of Ti41Zr25Be34 alloy can be obviously improved with the addition of alloying elements, and the most effective element is found to be Al. The mechanism for enhancing the creep resistance was discussed in terms of the scale variation of the shear transformation zone induced by alloying.

Atomic structure and formation of CuZrAl bulk metallic glasses and composites

International Nuclear Information System (INIS)

Kaban, I.; Jóvári, P.; Escher, B.; Tran, D.T.; Svensson, G.; Webb, M.A.; Regier, T.Z.; Kokotin, V.; Beuneu, B.; Gemming, T.; Eckert, J.

2015-01-01

Graphical abstract: Partial radial distribution functions for Cu 47.5 Zr 47.5 Al 5 metallic glass and relevant crystal structures. - Abstract: Cu 47.5 Zr 47.5 Al 5 metallic glass is studied experimentally by high-energy X-ray diffraction, neutron diffraction with isotopic substitution, electron diffraction and X-ray absorption spectroscopy. The atomic structure of the glass is modeled by reverse Monte-Carlo and molecular dynamics simulations. RMC modeling of seven experimental datasets enabled reliable separation of all partial pair distribution functions for Cu 47.5 Zr 47.5 Al 5 metallic glass. A peculiar structural feature of the ternary alloy is formation of the strong Al–Zr bonds, which are supposed to determine its high viscosity and enhanced bulk glass formation. Analysis of the local atomic order in Cu 47.5 Zr 47.5 Al 5 glass and Cu 10 Zr 7 , CuZr 2 and CuZr B2 crystalline structures elucidates their similarities and differences explaining the phase formation sequence by devitrification of the glass.

Synthesis and devitrification of high glass-forming ability bulk metallic glasses.

OpenAIRE

Huang, Hong.

2007-01-01

In this thesis, literature on the production, microstructures and properties of bulk metallic glasses (BMG) has been reviewed with particular reference to glass forming ability (GFA) and alloys of the Fe-Zr-B and Zr-based BMG systems. The experimental procedures used in the research are presented and the results for the amorphous Fe80Zr12B8 ribbon and the Zr57Ti5Al10Cu20Ni8, Zr57Nb5Al10Cu20Ni8, Zr53Nb2Al8Cu30Ni7 BMGs are given and discussed. Wedge-shaped ingots of the Zr-based BMGs were produ...

Designing biocompatible Ti-based metallic glasses for implant applications

International Nuclear Information System (INIS)

Calin, Mariana; Gebert, Annett; Ghinea, Andreea Cosmina; Gostin, Petre Flaviu; Abdi, Somayeh; Mickel, Christine; Eckert, Jürgen

2013-01-01

Ti-based metallic glasses show high potential for implant applications; they overcome in several crucial respects their well-established biocompatible crystalline counterparts, e.g. improved corrosion properties, higher fracture strength and wear resistance, increased elastic strain range and lower Young's modulus. However, some of the elements required for glass formation (e.g. Cu, Ni) are harmful for the human body. We critically reviewed the biological safety and glass forming tendency in Ti of 27 elements. This can be used as a basis for the future designing of novel amorphous Ti-based implant alloys entirely free of harmful additions. In this paper, two first alloys were developed: Ti 75 Zr 10 Si 15 and Ti 60 Nb 15 Zr 10 Si 15 . The overheating temperature of the melt before casting can be used as the controlling parameter to produce fully amorphous materials or bcc-Ti-phase reinforced metallic glass nano-composites. The beneficial effect of Nb addition on the glass-formation and amorphous phase stability was assessed by X-ray diffraction, transmission electron microscopy and differential scanning calorimetry. Crystallization and mechanical behavior of ribbons are influenced by the amount and distribution of the nano-scaled bcc phase existing in the as-cast state. Their electrochemical stability in Ringer's solution at 310 K was found to be significantly better than that of commercial Ti-based biomaterials; no indication for pitting corrosion was recorded. Highlights: ► Link between biocompatibility and glass-forming ability of alloying additions in Ti ► Selection of Ti–Zr–Si and Ti–Zr–Nb–Si glass-forming alloys ► Two novel glassy alloys were developed: Ti 75 Zr 10 Si 15 and Ti 60 Nb 15 Zr 10 Si 15. ► Glass-formation, thermal stability, corrosion and mechanical behavior were studied. ► Assessing the suitability for orthopedic applications.

In situ detection of two-stage crystallization in ZrTiCuNiBe under high pressure and high temperature

CERN Document Server

Sun, L L; Wu, Q; Zhan, Z J; Cao, L M; Wang, L M; Shao, G J; Zhang, J; Wang, W K

2002-01-01

Structural changes in bulk metallic Zr sub 4 sub 1 sub . sub 2 Ti sub 1 sub 3 sub . sub 8 Cu sub 1 sub 2 sub . sub 5 Ni sub 1 sub 0 Be sub 2 sub 2 sub . sub 5 glass subjected to heat treatments under high pressure were investigated by means of synchrotron radiation x-ray diffraction (SRXRD). In situ SRXRD measurements showed that the crystallization process of this material is comprised of two stages. Subsequent heating at 10 GPa converts the sample from the amorphous (Am) phase into a metastable fcc phase and then leads to the fcc phase changing back to the Am phase, indicating that there is a kind of 'reversible' phase transition phenomenon occurring in the alloy. Such phenomenon is explained on the basis of free energy considerations.

Improvement of the thermoplastic formability of Zr{sub 65}Cu{sub 17.5}Ni{sub 10}Al{sub 7.5} bulk metallic glass by minor addition of Erbium

Energy Technology Data Exchange (ETDEWEB)

Hu, Q. [Shenzhen Key Laboratory of Special Functional Materials, College of Materials Science and Engineering, Shenzhen 518060 (China); Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060 (China); Zeng, X.R., E-mail: zengxier@szu.edu.cn [Shenzhen Key Laboratory of Special Functional Materials, College of Materials Science and Engineering, Shenzhen 518060 (China); Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060 (China); JANUS Precision Components Co., LTD., Dongguan 523000 (China); Fu, M.W., E-mail: mmmwfu@polyu.edu.hk [Department of Mechanical Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong (China); Chen, S.S. [Shenzhen Key Laboratory of Special Functional Materials, College of Materials Science and Engineering, Shenzhen 518060 (China); Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060 (China); Jiang, J. [Institute of Applied Physics, Jiangxi Academy of Sciences, Nanchang 330029 (China)

2016-12-01

The softness of Zr{sub 65}Cu{sub 17.5}Ni{sub 10}Al{sub 7.5} bulk metallic glass (BMG) in the super-cooled liquid range (SCLR) is obviously improved by minor addition of 2% Er, which makes (Zr{sub 65}Cu{sub 17.5}Ni{sub 10}Al{sub 7.5}){sub 98}Er{sub 2} (Zr65Er2) to be a very formable Be-free Zr-based BMG. It is found the lower glass transition temperature of Zr65Er2 has an important contribution to the improvement of formability, which is contrary to the general understanding that the larger fragility and wider super-cooled liquid region (SCLR) are the major reasons for better thermoplastic formability. This finding is well explained by using the linear simplification of the SCLR in Angell plot. Zr65Er2 also has lower crystallization temperature and melting temperature, which is believed to be related to the formation of short-range ordering with lower transition energy rather than the composition shift to near eutectic. The above results help understand the effect of minor addition of rare-earth to the formability of Zr-based bulk metallic glasses.

Growth and microstructure formation of isothermally-solidified Zircaloy-4 joints brazed by a Zr-Ti-Cu-Ni amorphous alloy ribbon

Science.gov (United States)

Kim, K. H.; Lim, C. H.; Lee, J. G.; Lee, M. K.; Rhee, C. K.

2013-10-01

The microstructure and growth characteristics of Zircaloy-4 joints brazed by a Zr48Ti16Cu17Ni19 (at.%) amorphous filler metal have been investigated with regard to the controlled isothermal solidification and intermetallic formation. Two typical joints were produced depending on the isothermal brazing temperature: (1) a dendritic growth structure including bulky segregation in the central zone (at 850 °C), and (2) a homogeneous dendritic structure throughout the joint without segregation (at 890 °C). The primary α-Zr phase was solidified isothermally, nucleating to grow into a joint with a cellular or dendritic structure. Also, the continuous Zr2Ni and particulate Zr2Cu phases were formed in the segregated center zone and at the intercellular region, respectively, owing to the different solubility and atomic mobility of the solute elements (Ti, Cu, and Ni) in the α-Zr matrix. A disappearance of the central Zr2Ni phase was also rate-controlled by the outward diffusion of the Cu and Ni elements. When the detrimental Zr2Ni intermetallic phase was eliminated by a complete isothermal solidification at 890 °C, the strengths of the joints were high enough to cause yielding and fracture in the base metal, exceeding those of the bulk Zircaloy-4, at room temperature as well as at elevated temperatures (up to 400 °C).

Dynamic behaviors of a Zr-based bulk metallic glass under ramp wave and shock wave loading

Directory of Open Access Journals (Sweden)

Binqiang Luo

2015-06-01

Full Text Available Dynamic behaviors of Zr51Ti5Ni10Cu25Al9 bulk metallic glass were investigated using electric gun and magnetically driven isentropic compression device which provide shock and ramp wave loading respectively. Double-wave structure was observed under shock compression while three-wave structure was observed under ramp compression in 0 ∼ 18GPa. The HEL of Zr51Ti5Ni10Cu25Al9 is 8.97 ± 0.61GPa and IEL is 8.8 ± 0.3GPa, respectively. Strength of Zr51Ti5Ni10Cu25Al9 estimated from HEL is 5.0 ± 0.3GPa while the strength estimated from IEL is 3.6 ± 0.1GPa. Shock wave velocity versus particle velocity curve of Zr51Ti5Ni10Cu25Al9 under shock compression appears to be bilinear and a kink appears at about 18GPa. The Lagrangian sound speed versus particle velocity curve of Zr51Ti5Ni10Cu25Al9 under ramp wave compression exhibits two discontinuances and are divided to three regions: elastic, plastic-I and plastic-II. The first jump-down occurs at elastic-plastic transition and the second appears at about 17GPa. In elastic and plastic-I regions, Lagrangian sound speed increases linearly with particle velocity, respectively. Characteristic response of sound speed in plastic-I region disagree with shock result in the same pressure region(7GPa ∼ 18GPa, but is consistent with shock result at higher pressure(18-110GPa.

Correlation between microstructure and internal friction in a Zr41.2-Ti13.8-Cu12.5-Ni8- Be22.5-Fe2 bulk metallic glass

International Nuclear Information System (INIS)

Wang, Q.; Pelletier, J.M.; Da Dong, Y.; Ji, Y.F.; Xiu, H.

2004-01-01

The microstructural evolution in a Zr-Ti-Cu-Ni-Be-Fe bulk metallic glass (BMG) has been investigated by measurements of dynamical shear modulus and internal friction combined with other analytical methods such as differential scanning calorimetry (DSC), X-ray diffraction (XRD) and high resolution transmission electron microscopy (TEM). When heated from room temperature up to 873 K, the as-received BMG exhibits an exponential increase in internal friction accompanying the strong decrease of storage modulus and the presence of the first loss modulus peak during the dynamic glass transition, which can be well described using quasi-point defect model. The correlative changes of the mechanical response at higher temperature are associated with the crystallisation process of the supercooled liquid phase, which occurs in four different stages. It is shown that the main crystallisation process is completed in the first two stages. With further increasing temperature, the remaining amorphous phases crystallise and/or the metastable crystalline phases are transformed into the stable ones. Isothermal annealing were also performed at temperatures in the supercooled liquid region far below the onset temperature of the crystallisation process (T x ). Their influence on microstucture and internal friction behaviour of the BMG is also presented in this paper. The most striking result is that the internal friction is very sensitive to the local atomic short range ordering induced by the preheating treatment

Gaseous Phase and Electrochemical Hydrogen Storage Properties of Ti50Zr1Ni44X5 (X = Ni, Cr, Mn, Fe, Co, or Cu for Nickel Metal Hydride Battery Applications

Directory of Open Access Journals (Sweden)

Jean Nei

2016-07-01

Full Text Available Structural, gaseous phase hydrogen storage, and electrochemical properties of a series of the Ti50Zr1Ni44X5 (X = Ni, Cr, Mn, Fe, Co, or Cu metal hydride alloys were studied. X-ray diffraction (XRD and scanning electron microscopy (SEM revealed the multi-phase nature of all alloys, which were composed of a stoichiometric TiNi matrix, a hyperstoichiometric TiNi minor phase, and a Ti2Ni secondary phase. Improvement in synergetic effects between the main TiNi and secondary Ti2Ni phases, determined by the amount of distorted lattice region in TiNi near Ti2Ni, was accomplished by the substitution of an element with a higher work function, which consequently causes a dramatic increase in gaseous phase hydrogen storage capacity compared to the Ti50Zr1Ni49 base alloy. Capacity performance is further enhanced in the electrochemical environment, especially in the cases of the Ti50Zr1Ni49 base alloy and Ti50Zr1Ni44Co5 alloy. Although the TiNi-based alloys in the current study show poorer high-rate performances compared to the commonly used AB5, AB2, and A2B7 alloys, they have adequate capacity performances and also excel in terms of cost and cycle stability. Among the alloys investigated, the Ti50Zr1Ni44Fe5 alloy demonstrated the best balance among capacity (394 mAh·g−1, high-rate performance, activation, and cycle stability and is recommended for follow-up full-cell testing and as the base composition for future formula optimization. A review of previous research works regarding the TiNi metal hydride alloys is also included.

Experimental investigation of phase equilibria in the Zr-Cu-Ni ternary system

International Nuclear Information System (INIS)

Yang, Mujin; Wang, Cuiping; Yang, Shuiyuan; Shi, Zhan; Han, Jiajia; Liu, Xingjun

2017-01-01

The phase equilibria in the Zr-Cu-Ni ternary system are investigated combined with X-ray diffraction, electron probe micro-analysis and differential scanning calorimetry. Two isothermal sections of the Zr-Cu-Ni ternary system at 1 000 C and 1 100 C are experimentally established. Most of the binary intermetallic compounds, e.g. Zr 7 Ni 10 , ZrNi, ZrNi 5 , Zr 14 Cu 51 , and Zr 2 Cu 9 , show a remarkable ternary solubility. A new ternary compound named τ 3 (Zr 31.1-30.7 . Cu 28.5-40.3 Ni 40.4-29.0 ) is detected at 1 000 C and dissolved at 1 020 C because the nearby large liquid phase field further expands. The newly determined phase equilibria will provide important information for both thermodynamic assessment and alloy design of Zr-based metallic glass.

Stress overshoot in stress-strain curves of Zr65Al10Ni10Cu15 metallic glass

International Nuclear Information System (INIS)

Kawamura, Y.; Shibata, T.; Inoue, A.; Masumoto, T.

1997-01-01

The essential features of the stress overshoot in the stress-strain curves of Zr 65 Al 10 Ni 10 Cu 15 (at.%) metallic glass that has a wide supercooled liquid region were revealed. The stress overshoot was dependent on temperature, strain rate, and stress relaxation. During the stretch, a change in strain rate gave rise to stress overshoot or undershoot which was sensitive to the variable quantities in the strain rate. copyright 1997 American Institute of Physics

Glass-Forming Ability and Early Crystallization Kinetics of Novel Cu-Zr-Al-Co Bulk Metallic Glasses

Directory of Open Access Journals (Sweden)

Xiaoliang Han

2016-09-01

Full Text Available In recent years, CuZr-based bulk metallic glass (BMG composites ductilized by a shape memory B2 CuZr phase have attracted great attention owing to their outstanding mechanical properties. However, the B2 CuZr phase for most CuZr-based glass-forming compositions is only stable at very high temperatures, leading to the uncontrollable formation of B2 crystals during quenching. In this work, by introducing Co (i.e., 4, 5, and 6 at. % and 10 at. % Al into CuZr-based alloys, the relatively good glass-forming ability (GFA of CuZr-based alloys still can be achieved. Meanwhile, the B2 phase can be successfully stabilized to lower temperatures than the final temperatures of crystallization upon heating CuZr-based BMGs. Unlike previous reported CuZr-based BMGs, the primary crystallization products upon heating are mainly B2 CuZr crystals but not CuZr2 and Cu10Zr7 crystals. Furthermore, the primary precipitates during solidification are still dominated by B2 crystals, whose percolation threshold is detected to lie between 10 ± 2 vol. % and 31 ± 2 vol. %. The crystallization kinetics underlying the precipitation of B2 crystals was also investigated. Our results show that the present glass-forming composites are promising candidates for the fabrication of ductile CuZr-based BMG composites.

Computer simulations of nanoindentation in Mg-Cu and Cu-Zr metallic glasses

DEFF Research Database (Denmark)

Paduraru, Anca; Andersen, Ulrik Grønbjerg; Thyssen, Anders

2010-01-01

The formation of shear bands during plastic deformation of Cu0.50Zr0.50 and Mg0.85Cu0.15 metallic glasses is studied using atomic-scale computer simulations. The atomic interactions are described using realistic many-body potentials within the effective medium theory, and are compared with similar...... simulations using a Lennard-Jones description of the material. The metallic glasses are deformed both in simple shear and in a simulated nanoindentation experiment. Plastic shear localizes into shear bands with a width of approximately 5 nm in CuZr and 8 nm in MgCu. In simple shear, the shear band formation...... is very clear, whereas only incipient shear bands are seen in nanoindentation. The shear band formation during nanoindentation is sensitive to the indentation velocity, indenter radius and the cooling rate during the formation of the metallic glass. For comparison, a similar nanoindentation simulation...

Distribution of oxides in a Zr-Cu-Ni-Al-Nb-Si bulk metallic glass

Energy Technology Data Exchange (ETDEWEB)

Heinrich, Jochen; Busch, Ralf [Chair of Metallic Materials, Saarland University, PO Box 151150, 66041 Saarbruecken (Germany); Mueller, Frank; Huefner, Stefan [Chair of Experimental Physics, Saarland University, PO Box 151150, 66041 Saarbruecken (Germany)

2010-07-01

The course of oxide presence with distance from the sample surface and bonding partner was studied for the bulk metallic glass with the nominal composition Zr{sub 57.9}Cu{sub 15.4}Ni{sub 12.7}Al{sub 10.2}Nb{sub 2.8}Si{sub 1} (at%) by X-ray photoelectron spectroscopy (XPS). Investigated specimens are taken from vacuum quench-cast rods subjected to oxidation at room temperature and atmosphere. Binding energies were determined in various depths using ion beam ablation of up to 100 nanometers. XPS spectra confirm oxidation primarily of the pure zirconium and aluminum constituents, all other peaks correspond to metallic bonds. While the surface area shows a passivating zirconia layer a few nanometers thick, oxygen is bonded predominantly with aluminum inside the bulk. Since the concentration of oxygen is a crucial factor in the crystallization behavior of bulk metallic glass forming liquids on basis of oxygen affine metals, so far only high purity materials were thought to be suitable. The findings in this study, however, are promising for alloys with industrial grade elements with sufficient glass forming ability. Comparisons of the alloy with differing oxygen content support the conclusion that aluminum acts as an appropriate scavenger for both adsorbed and large amounts of intrinsic oxygen in zirconium based amorphous metals.

Correlation between local structure and stability of supercooled liquid state in Zr-based metallic glasses

International Nuclear Information System (INIS)

Saida, Junji; Imafuku, Muneyuki; Sato, Shigeo; Sanada, Takashi; Matsubara, Eiichiro; Inoue, Akihisa

2007-01-01

The correlation between the local structure and stability of supercooled liquid state is investigated in the Zr 70 (Ni, Cu) 30 binary and Zr 70 Al 10 (Ni, Cu) 20 (numbers indicate at.%) ternary metallic glasses. The Zr 70 Ni 30 binary amorphous alloy with a low stability of supercooled liquid state has a tetragonal Zr 2 Ni-like local structure around Ni atom. Meanwhile, the Zr 70 Cu 30 binary metallic glass has a different local structure of tetragonal Zr 2 Cu, where we suggest the icosahedral local structure by the quasicrystallization behavior in addition of a very small amount of noble metals. The effect of Al addition on the local structure in the Zr-Ni alloy is also examined. We have investigated that the dominant local structure changes in the icosahedral-like structure from the tetragonal Zr 2 Ni-like local structure by the Al substitution with Ni accompanying with the significant stabilization of supercooled liquid state. It is concluded that the formation of icosahedral local structure contributes to the enhancement of stability of supercooled liquid state in the Zr-based alloys

Thermal and mechanical properties of the Zr53Cu30Ni9Al8 based bulk metallic glass microalloyed with silicon

International Nuclear Information System (INIS)

Jang, Jason S.C.; Jian, S.R.; Chang, C.F.; Chang, L.J.; Huang, Y.C.; Li, T.H.; Huang, J.C.; Liu, C.T.

2009-01-01

The amorphous alloy rods of (Zr 53 Cu 30 Ni 9 Al 8 ) 100-x Si x (x = 0.25, 0.5, 0.75, 1) with a diameter of 2-6 mm were prepared by drop casting method in an Ar atmosphere. The thermal properties, including glass forming ability (GFA) and thermal stability during isothermal annealing of these amorphous alloys, and the mechanical properties have been systematic investigated by the combination of DSC, XRD, SEM, TEM, and compression test. The result of X-ray diffraction reveals that these entire (Zr 53 Cu 30 Ni 9 Al 8 ) 100-x Si x alloy rods exhibit a typical amorphous diffraction pattern with only a broad maximum around 2θ around 40 degree. Both T g (glass transition temperature) and T x (crystallization temperature) of these (Zr 53 Cu 30 Ni 9 Al 8 ) 100-x Si x alloys increase with the silicon addition. In addition, both the activation energy of crystallization and the incubation time of isothermal annealing these (Zr 53 Cu 30 Ni 9 Al 8 ) 100-x Si x amorphous alloys indicate that the (Zr 53 Cu 30 Ni 9 Al 8 ) 99.25 Si 0.75 alloy possesses the best thermal stability in the (Zr 53 Cu 30 Ni 9 Al 8 ) 100-x Si x alloy system. In parallel, the result of compression test shows that the yield strength increases with the addition of Si content and reaches to a maximum value about 1750 MPa with 3% plastic strain for the (Zr 53 Cu 30 Ni 9 Al 8 ) 99.25 Si 0.75 amorphous alloy.

Experimental investigation of phase equilibria in the Zr-Cu-Ni ternary system

Energy Technology Data Exchange (ETDEWEB)

Yang, Mujin; Wang, Cuiping; Yang, Shuiyuan; Shi, Zhan; Han, Jiajia; Liu, Xingjun [Xiamen Univ. (China). College of Materials and Fujian Provincial Key Lab. of Materials Genome

2017-08-15

The phase equilibria in the Zr-Cu-Ni ternary system are investigated combined with X-ray diffraction, electron probe micro-analysis and differential scanning calorimetry. Two isothermal sections of the Zr-Cu-Ni ternary system at 1 000 C and 1 100 C are experimentally established. Most of the binary intermetallic compounds, e.g. Zr{sub 7}Ni{sub 10}, ZrNi, ZrNi{sub 5}, Zr{sub 14}Cu{sub 51}, and Zr{sub 2}Cu{sub 9}, show a remarkable ternary solubility. A new ternary compound named τ{sub 3} (Zr{sub 31.1-30.7} . Cu{sub 28.5-40.3}Ni{sub 40.4-29.0}) is detected at 1 000 C and dissolved at 1 020 C because the nearby large liquid phase field further expands. The newly determined phase equilibria will provide important information for both thermodynamic assessment and alloy design of Zr-based metallic glass.

New Ti-based Ti–Cu–Zr–Fe–Sn–Si–Ag bulk metallic glass for biomedical applications

Energy Technology Data Exchange (ETDEWEB)

Pang, Shujie; Liu, Ying; Li, Haifei; Sun, Lulu [Key Laboratory of Aerospace Materials and Performance (Ministry of Education), School of Materials Science and Engineering, Beihang University, Beijing 100191 (China); Li, Yan [Key Laboratory of Aerospace Materials and Performance (Ministry of Education), School of Materials Science and Engineering, Beihang University, Beijing 100191 (China); Beijing Key Laboratory for Advanced Functional Materials and Thin Film Technology, Beihang University, Beijing 100191 (China); Zhang, Tao, E-mail: zhangtao@buaa.edu.cn [Key Laboratory of Aerospace Materials and Performance (Ministry of Education), School of Materials Science and Engineering, Beihang University, Beijing 100191 (China)

2015-03-15

Highlights: • Novel Ti{sub 47}Cu{sub 38}Zr{sub 7.5}Fe{sub 2.5}Sn{sub 2}Si{sub 1}Ag{sub 2} (at.%) bulk metallic glass (BMG) with a critical diameter of 7 mm was discovered. • The present BMG is the largest Ni- and Be-free Ti-based BMG containing low content of noble metal reported to date. • The glassy alloy possesses high specific strength, low Young’s modulus, and good corrosion resistance and bio-compatibility. • Combination of high glass-forming ability and good mechano- and bio-compatibility for the Ti-based BMG demonstrates the potential for use in biomedical applications. - Abstract: A novel Ni-free Ti{sub 47}Cu{sub 38}Zr{sub 7.5}Fe{sub 2.5}Sn{sub 2}Si{sub 1}Ag{sub 2} (at.%) bulk metallic glass (BMG) with superior glass-forming ability, good mechanical properties and excellent biocompatibility was discovered. The Ti-based BMG with a diameter of 7 mm can be prepared by copper mold casting and the supercooled liquid region was 52 K. Compressive strength, specific strength, Young’s modulus and microhardness of the Ti-based BMG were about 2.08 GPa, 3.2 × 10{sup 5} N m/kg, 100 GPa and 588 Hv, respectively. Electrochemical measurements indicated that the Ti-based glassy alloy possesses higher corrosion resistance than Ti–6Al–4V alloy in a simulated body fluid environment. Attachment, spreading out and proliferation of MC3T3-E1 cells on the Ti-based BMG surface demonstrated the excellent biocompatibility. Mechanisms of the formation and properties for the Ti-based glassy alloy are also discussed. The combination of high glass-forming ability, excellent mechanical properties, high corrosion resistance and good biocompatibility demonstrates the potential of the Ni-free Ti-based BMG for use in biomedical applications.

New Ti-based Ti–Cu–Zr–Fe–Sn–Si–Ag bulk metallic glass for biomedical applications

International Nuclear Information System (INIS)

Pang, Shujie; Liu, Ying; Li, Haifei; Sun, Lulu; Li, Yan; Zhang, Tao

2015-01-01

Highlights: • Novel Ti 47 Cu 38 Zr 7.5 Fe 2.5 Sn 2 Si 1 Ag 2 (at.%) bulk metallic glass (BMG) with a critical diameter of 7 mm was discovered. • The present BMG is the largest Ni- and Be-free Ti-based BMG containing low content of noble metal reported to date. • The glassy alloy possesses high specific strength, low Young’s modulus, and good corrosion resistance and bio-compatibility. • Combination of high glass-forming ability and good mechano- and bio-compatibility for the Ti-based BMG demonstrates the potential for use in biomedical applications. - Abstract: A novel Ni-free Ti 47 Cu 38 Zr 7.5 Fe 2.5 Sn 2 Si 1 Ag 2 (at.%) bulk metallic glass (BMG) with superior glass-forming ability, good mechanical properties and excellent biocompatibility was discovered. The Ti-based BMG with a diameter of 7 mm can be prepared by copper mold casting and the supercooled liquid region was 52 K. Compressive strength, specific strength, Young’s modulus and microhardness of the Ti-based BMG were about 2.08 GPa, 3.2 × 10 5 N m/kg, 100 GPa and 588 Hv, respectively. Electrochemical measurements indicated that the Ti-based glassy alloy possesses higher corrosion resistance than Ti–6Al–4V alloy in a simulated body fluid environment. Attachment, spreading out and proliferation of MC3T3-E1 cells on the Ti-based BMG surface demonstrated the excellent biocompatibility. Mechanisms of the formation and properties for the Ti-based glassy alloy are also discussed. The combination of high glass-forming ability, excellent mechanical properties, high corrosion resistance and good biocompatibility demonstrates the potential of the Ni-free Ti-based BMG for use in biomedical applications

Effects of superimposed hydrostatic pressure on flow and fracture of a Zr-Ti-Ni-Cu-Be bulk amorphous alloy

International Nuclear Information System (INIS)

Lowhaphandu, P.; Montgomery, S.L.; Lewandowski, J.J.

1999-01-01

Recent successes in producing bulk amorphous alloys have renewed interest in this class of materials. Although amorphous metallic alloys have been shown to exhibit strengths in excess of 2.0 GPa, most of the earlier studies on such materials were conducted on tape or ribbon specimens due to the high cooling rates required to achieve the amorphous structure. The primary purpose of this investigation was to determine the effects of superimposed hydrostatic pressure on the flow and fracture behavior of a Zr-Ti-Ni-Cu-Be bulk metallic glass utilizing procedures successfully utilized on a range of structural materials, as reviewed recently. In general, few studies of this type have been conducted on metallic glasses, although thin ribbons (i.e., 300 microm thick) of a Pd-Cu-Si amorphous material tested with superimposed pressure have been reported previously. In particular, the effects of superimposed hydrostatic pressure over levels ranging from 50 MPa to 575 MPa on the flow/fracture behavior of cylindrical tensile specimens were compared to the flow and fracture behavior of identical materials tested in uniaxial tension and compression. It is shown that changes in stress triaxiality, defined as σ m /bar σ, over the range of -0.33 to 0.33 produced a negligible effect on the fracture stress and fracture strain, while the orientation of the macroscopic fracture plane with respect to the loading axis was significantly affected by changes in σ m /bar σ

Composition design and mechanical properties of ternary Cu–Zr–Ti bulk metallic glasses

International Nuclear Information System (INIS)

Pan, Ye; Zeng, Yuqiao; Jing, Lijun; Zhang, Lu; Pi, Jinhong

2014-01-01

Highlights: • Newly designed monolithic bulk metallic glasses are of good glass-forming ability. • Cu 50 Zr 44 Ti 6 exhibits excellent plastic deformation up to ∼7.4%. • Copious and intersected shear bans are observed in the fractography of Cu 50 Zr 44 Ti 6 . • Cu 50 Zr 44 Ti 6 has the best plasticity in the ternary Cu–Zr–Ti bulk metallic glasses. - Abstract: The new compositions of ternary Cu–Zr–Ti bulk metallic glasses are predicted by integrating calculation of vacancy formation energy, mixing enthalpy and configuration entropy of the alloys based on thermodynamics of glass formers. The monolithic amorphous rods of 3 mm diameter have been successfully fabricated, and characterized by X-ray diffractometry, differential scanning calorimetry, scanning electronic microscopy, transmission electronic microscopy and compression tests. The results show that the designed alloys possess good glass forming ability and excellent mechanical properties. The mechanical properties of the samples can be effectively improved by regulating their composition. The monolithic amorphous rod of Cu 50 Zr 44 Ti 6 exhibits a high fracture strength of 1855 MPa and excellent plastic deformation up to ∼7.4%. The formation and propagation of shear bands in samples are also investigated. The enhancement of plastic deformation is mainly contributed to multiplication and intersection of shear bands

Effects of Fabrication Parameters on Interface of Zirconia and Ti-6Al-4V Joints Using Zr55Cu30Al10Ni5 Amorphous Filler

Science.gov (United States)

Liu, Yuhua; Hu, Jiandong; Shen, Ping; Guo, Zuoxing; Liu, Huijie

2013-09-01

ZrO2 was brazed to Ti-6Al-4V using a Zr55Cu30Al10Ni5 (at.%) amorphous filler in a high vacuum at 1173-1273 K. The influences of brazing temperature, holding time, and cooling rate on the microstructure and shear strength of the joints were investigated. The interfacial microstructures can be characterized as ZrO2/ZrO2- x + TiO/(Zr,Ti)2(Cu,Ni)/(Zr,Ti)2(Cu,Ni,Al)/acicular Widmanstäten structure/Ti-6Al-4V. With the increase in the brazing temperature, both the thickness of the ZrO2- x + TiO layer and the content of the (Zr,Ti)2(Cu,Ni) phase decreased. However, the acicular Widmanstäten structure gradually increased. With the increase in the holding time, the (Zr,Ti)2(Cu,Ni) phase decreased, and the thickness of the (Zr,Ti)2(Cu,Ni) + (Zr,Ti)2(Cu,Ni,Al) layer decreased. In addition, cracks formed adjacent to the ZrO2 side under rapid cooling. The microstructures produced under various fabrication parameters directly influence the shear strength of the joints. When ZrO2 and Ti-6Al-4V couples were brazed at 1173 K for 10 min and then cooled at a rate of 5 K/min, the maximum shear strength of 95 MPa was obtained.

Study on glass formation and crystallization of Zr54.5Cu20Al10Ni8Ti75 alloy

International Nuclear Information System (INIS)

Neogy, S.; Tewari, R.; Srivastava, D.; Dey, G.K.; Banerjee, S.; Vaibhaw, K.

2009-01-01

The microstructure of Zr 54.5 Cu 20 Al 10 Ni 8 Ti 75 alloy has been examined after solidification involving three different techniques viz., copper mould casting, suction casting and melt spinning. The bulk glass microstructure of the alloy obtained through copper mould casting was found to comprise of big cube Zr 2 Ni phase in a dendritic morphology and tetragonal Zr 2 Ni phase in a faulted morphology besides the amorphous phase. High-resolution electron microscopy (HREM) was carried out to examine the internal structure and interface structure of the phases. The dendritic phase was found to consist of primary and secondary dendrite arms with faceted as well rounded interfaces with the amorphous phase. Ledges were noticed at either of the interfaces with higher density at the rounded interfaces. The presence of the faulted phase was noticed in between dendritic arms. The faulted phase was found to consist of different domains corresponding to different orientations. A variety of interfaces could be noticed between these individual domains and also within a single domain itself. At least three different kinds of faulted region were identified to coexist in a single domain. The melt spun ribbon and bulk glass made through suction casting was found to be fully amorphous. The amorphous phase obtained from the three different techniques showed different degrees of medium range order as revealed by the fluctuation microscopy technique. Crystallization behavior of as solidified structures has been examined by comparing the crystallization kinetics and microstructure. Crystallization led to the transformation of the amorphous phase to nanocrystals in all the cases. The crystallization event was found to be singular in the case of copper mold cast bulk glass and multiple in the case of suction cast bulk glass and ribbon. The phase forming on crystallization was found to be the same faulted tetragonal Zr 2 Ni that was encountered during solidification. Multiple domains

Numerical Simulation of Brazing TiC Cermet to Iron with TiZrNiCu Filler Metal

Institute of Scientific and Technical Information of China (English)

Lixia ZHANG; Jicai FENG

2004-01-01

The maximum thermal stress and stress concentration zones of iron/TiC cermet joint during cooling were studied in this paper. The results showed that the shear stress on iron/TiC cermet joint concentrates on the interface tip and the maximum shear stress appears on the left tip of iron/TiZrNiCu interlace. Positive tensile stress on TiC cermet undersurface concentrates on both sides of TiC cermet and its value decreases during cooling. Negative tensile stress on TiC cermet undersurface concentrates on the center of TiC cermet and its value increases during cooling. Brazing temperature has little effect on the development and maximum thermal stress.

Comparative study of local atomic structures in Zr{sub 2}Cu{sub x}Ni{sub 1−x} (x = 0, 0.5, 1) metallic glasses

Energy Technology Data Exchange (ETDEWEB)

Huang, Yuxiang [Department of Physics, South University of Science and Technology of China, Shenzhen, Guangdong 518055 (China); Huang, Li, E-mail: huangl@sustc.edu.cn [Department of Physics, South University of Science and Technology of China, Shenzhen, Guangdong 518055 (China); Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011 (United States); Wang, C. Z.; Ho, K. M. [Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011 (United States); Department of Physics, Iowa State University, Ames, Iowa 50011 (United States); Kramer, M. J. [Ames Laboratory, U.S. Department of Energy, Ames, Iowa 50011 (United States); Materials Science and Engineering, Iowa State University, Ames, Iowa 50011 (United States)

2015-11-21

Extensive analysis has been performed to understand the key structural motifs accounting for the difference in glass forming ability in the Zr-Cu and Zr-Ni binary alloy systems. Here, the reliable atomic structure models of Zr{sub 2}Cu{sub x}Ni{sub 1−x} (x = 0, 0.5, 1) are constructed using the combination of X-ray diffraction experiments, ab initio molecular dynamics simulations and a constrained reverse Monte Carlo method. We observe a systematic variation of the interatomic distance of different atomic pairs with respect to the alloy composition. The ideal icosahedral content in all samples is limited, despite the high content of five-fold symmetry motifs. We also demonstrate that the population of Z-clusters in Zr{sub 2}Cu glass is much higher than that in the Zr{sub 2}Ni and Zr{sub 2}Cu{sub 0.5}Ni{sub 0.5} samples. And Z12 〈0, 0, 12, 0〉 Voronoi polyhedra clusters prefer to form around Cu atoms, while Ni-centered clusters are more like Z11 〈0, 2, 8, 1〉 clusters, which is less energetically stable compared to Z12 clusters. These two different structural properties may account for the higher glass forming ability of Zr{sub 2}Cu alloy than that of Zr{sub 2}Ni alloy.

Deformation behavior, corrosion resistance, and cytotoxicity of Ni-free Zr-based bulk metallic glasses.

Science.gov (United States)

Liu, L; Qiu, C L; Chen, Q; Chan, K C; Zhang, S M

2008-07-01

Two Ni-free bulk metallic glasses (BMGs) of Zr(60)Nb(5)Cu(22.5)Pd(5)Al(7.5) and Zr(60)Nb(5)Cu(20)Fe(5)Al(10) were successfully prepared by arc-melting and copper mold casting. The thermal stability and crystallization were studied using differential scanning calorimetry. It demonstrates that the two BMGs exhibit very good glass forming ability with a wide supercooled liquid region. A multi-step process of crystallization with a preferential formation of quasicrystals occurred in both BMGs under continuous heating. The deformation behavior of the two BMGs was investigated using quasi-static compression testing. It reveals that the BMGs exhibit not only superior strength but also an extended plasticity. Corrosion behaviors of the BMGs were investigated in phosphate buffered solution by electrochemical polarization. The result shows that the two BMGs exhibit excellent corrosion resistance characterized by low corrosion current densities and wide passive regions. X-ray photoelectron spectroscopy analysis revealed that the passive film formed after anodic polarization was highly enriched in zirconium, niobium, and aluminum oxides. This is attributed to the excellent corrosion resistance. Additionally, the potential cytotoxicity of the two Ni-free BMGs was evaluated through cell culture for 1 week followed by 3-(4,5-Dimethylthiazol-2-yl-)-2,5-diphenyltetrazolium bromide assay and SEM observation. The results indicate that the two Ni-free BMGs exhibit as good biocompatibility as Ti-6Al-4V alloy, and thus show a promising potential for biomedical applications. (c) 2007 Wiley Periodicals, Inc.

Formation, thermal stability and mechanical properties of bulk glassy alloys with a diameter of 20 mm in Zr-(Ti,Nb)-Al-Ni-Cu system

International Nuclear Information System (INIS)

Inoue, A.; Zhang, Q.S.; Zhang, W.; Yubuta, K.; Son, K.S.; Wang, X.M.

2009-01-01

Bulk glassy alloy rods with a diameter of 20 mm were produced for Zr 61 Ti 2 Nb 2 Al 7.5 Ni 10 Cu 17.5 and Zr 60 Ti 2 Nb 2 Al 7.5 Ni 10 Cu 18.5 by a tilt casting method. The replacement of Zr by a small amount of Ti and Nb caused a distinct increase in the maximum diameter from 16 mm for Zr 65 Al 7.5 Ni 10 Cu 17.5 to 20 mm, accompanying the decrease in liquidus temperature and the increase in reduced glass transition temperature. The primary precipitation phase from supercooled liquid also shows a distinct change, i.e., from coexistent Zr 2 Cu, Zr 2 Ni and Zr 6 NiAl 2 phases for the 65%Zr alloy to an icosahedral phase for the 61%Zr and 60%Zr alloys. These results allow us to presume that the enhancement of the glass-forming ability is due to an increase in the stability of supercooled liquid against crystallization caused by the development of icosahedral short-range ordered atomic configurations. The 60%Zr specimens taken from the central and near-surface regions in the transverse cross section at the site which is 15 mm away from the bottom surface of the cast glassy rod with a diameter of 20 mm exhibit good mechanical properties under a compressive deformation mode, i.e., Young's modulus of 81 GPa, large elastic strain of 0.02, high yield strength of 1610 MPa and distinct plastic strain of 0.012. Besides, a number of shear bands are observed along the maximum shear stress plane on the peripheral surface near the final fracture site. The finding of producing the large scale Zr-based bulk glassy alloys exhibiting reliable mechanical properties is encouraging for future advancement of bulk glassy alloys as a new type of functional material. (author)

High-pressure x-ray diffraction of icosahedral Zr-Al-Ni-Cu-Ag quasicrystals

DEFF Research Database (Denmark)

Jiang, Jianzhong; Saksl, Karel; Rasmussen, Helge Kildahl

2001-01-01

temperature using synchrotron radiation. The icosahedral quasicrystal structure is retained up to the highest hydrostatic pressure used (approximately 28 GPa) and is reversible after decompression. The bulk modulus at zero pressure and its pressure derivative of the icosahedral Zr-Al-Ni-Cu-Ag quasicrystal......The effect of pressure on the structural stability of icosahedral Zr-Al-Ni-Cu-Ag quasicrystals forming from a Zr65Al7.5Ni10Cu7.5Ag10 metallic glass with a supercooled liquid region of 44 K has been investigated by in situ high-pressure angle-dispersive x-ray powder diffraction at ambient......-Al-Ni-Cu-Ag quasicrystals induced by pressure....

Effect of Ga substitution on the crystallization behaviour and glass forming ability of Zr-Al-Cu-Ni alloys

International Nuclear Information System (INIS)

Singh, Devinder; Yadav, T.P.; Mandal, R.K.; Tiwari, R.S.; Srivastava, O.N.

2010-01-01

The crystallization behaviour of melt spun Zr 69.5 Al 7.5-x Ga x Cu 12 Ni 11 (x = 0-7.5; in at.%) metallic glasses has been investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). The DSC traces showed changes in crystallization behaviour with substitution of Ga. Formation of single nano-quasicrystalline phase by controlled crystallization of glasses has been found only for 0 ≤ x ≤ 1.5. Further increase of Ga content gives rise to formation of the quasicrystals together with Zr 2 Cu type crystalline phase. In addition to this, the substitution of Ga influences the size and shape of nano-quasicrystals. The glass forming abilities (GFAs) of these metallic glasses were assessed by the recognition of glass forming ability indicators, i.e. reduced glass transition temperature (T rg ) and supercooled liquid region (ΔT x ). The glass transition temperature (T g ) has been observed for all the melt spun ribbons.

Interatomic potential to predict the favored and optimized compositions for ternary Cu-Zr-Hf metallic glasses

International Nuclear Information System (INIS)

Luo, S. Y.; Cui, Y. Y.; Dai, Y.; Li, J. H.; Liu, B. X.

2012-01-01

Under the framework of smoothed and long range second-moment approximation of tight-binding, a realistic interatomic potential was first constructed for the Cu-Zr-Hf ternary metal system. Applying the constructed potential, Monte Carlo simulations were carried out to compare the relative stability of crystalline solid solution versus its disordered counterpart over the entire composition triangle of the system (as a function of alloy composition). Simulations not only reveal that the origin of metallic glass formation but also determine, in the composition triangle, a quadrilateral region, within which metallic glass formation is energetically favored. It is proposed to define the energy differences between the crystalline solid solutions and disordered states as the driving force for amorphization and the corresponding calculations pinpoint an optimized composition locating at an composition of Cu 55 Zr 10 Hf 35 , around which the driving force for metallic glass formation reaches its maximum, suggesting that the ternary Cu-Zr-Hf metallic glasses designed to have the compositions around Cu 55 Zr 10 Hf 35 could be more stable than other alloys in the system. Moreover, for the Cu 55 Zr 10 Hf 35 metallic glass, the Voronoi tessellation calculations reveal some interesting features of its atomic configurations and coordination polyhedra distribution.

Influence of air and vacuum environment on fatigue behavior of Zr-based bulk metallic glasses

International Nuclear Information System (INIS)

Wang, G.Y.; Liaw, P.K.; Yokoyama, Y.; Peter, W.H.; Yang, B.; Freels, M.; Buchanan, R.A.; Liu, C.T.; Brooks, C.R.

2007-01-01

High-cycle fatigue (HCF) experiments in air and vacuum at room temperature were conducted on zirconium (Zr)-based bulk-metallic glasses (BMGs): Zr 50 Cu 40 Al 10 , Zr 50 Cu 30 Al 10 Ni 10 , and Zr 50 Cu 37 Al 10 Pd 3 in atomic percent. The fatigue-endurance limit of Zr 50 Cu 37 Al 10 Pd 3 was found to be significantly greater than those of Zr 50 Cu 40 Al 10 and Zr 50 Cu 30 Al 10 Ni 10 , which indicates that the inclusions of Pd and the resulting nano structures improve the fatigue resistances of the Zr-based BMGs. The fatigue lives in vacuum and air were generally found to be comparable

Influence of in situ synthesized TiC on thermal stability and corrosion behavior of Zr60Cu10Al15Ni15 amorphous composites

International Nuclear Information System (INIS)

Geng, Jiwei; Teng, Xinying; Zhou, Guorong; Leng, Jinfeng; Zhao, Degang

2014-01-01

In situ synthesized TiC particles were prepared by a thermal explosion method. Adding “in situ synthesized” TiC into Zr 60 Cu 10 Al 15 Ni 15 glass matrix to obtain amorphous matrix composites was achieved. The corrosion behavior of Zr 60 Cu 10 Al 15 Ni 15 amorphous composites was evaluated using potentiodynamic polarization measurements in 3.5 wt% NaCl solution at room temperature. The results show that the microhardness and thermal stability are improved apparently, while the TiC (≤0.6 wt%) does not significantly affect the supercooled liquid behavior. Moreover, the corrosion resistance is improved apparently because the nanocrystals accelerate the diffusion of passive elements for faster formation of the protective passive film at nanocrystals/amorphous interfaces. However, when the TiC content is more than 0.6 wt%, both glass forming ability and corrosion resistance are reduced significantly

Effects of Al addition on atomic structure of Cu-Zr metallic glass

Science.gov (United States)

Li, Feng; Zhang, Huajian; Liu, Xiongjun; Dong, Yuecheng; Yu, Chunyan; Lu, Zhaoping

2018-02-01

The atomic structures of Cu52Zr48 and Cu45Zr48Al7 metallic glasses (MGs) have been studied by molecular dynamic simulations. The results reveal that the molar volume of the Cu45Zr48Al7 MG is smaller than that of the Cu52Zr48 MG, although the size of the Al atom is larger than that of the Cu atom, implying an enhanced atomic packing density achieved by introducing Al into the ternary MG. Bond shortening in unlike atomic pairs Zr-Al and Cu-Al is observed in the Cu45Zr48Al7 MG, which is attributed to strong interactions between Al and (Zr, Cu) atoms. Meanwhile, the atomic packing efficiency is enhanced by the minor addition of Al. Compared with the Cu52Zr48 binary MG, the potential energy of the ternary MG decreases and the glass transition temperature increases. Structural analyses indicate that more Cu- and Al-centered full icosahedral clusters emerge in the Cu45Zr48Al7 MG as some Cu atoms are substituted by Al. Furthermore, the addition of Al leads to more icosahedral medium-range orders in the ternary MG. The increase of full icosahedral clusters and the enhancement of the packing density are responsible for the improved glass-forming ability of Cu45Zr48Al7.

Calculation of Gibbs energy of Zr-Al-Ni, Zr-Al-Cu, Al-Ni-Cu and Zr-Al-Ni-Cu liquid alloys based on quasiregular solution model

International Nuclear Information System (INIS)

Li, H.Q.; Yang, Y.S.; Tong, W.H.; Wang, Z.Y.

2007-01-01

With the effects of electronic structure and atomic size being introduced, the mixing enthalpy as well as the Gibbs energy of the ternary Zr-Al-Cu, Ni-Al-Cu, Zr-Ni-Al and quaternary Zr-Al-Ni-Cu systems are calculated based on quasiregular solution model. The computed results agree well with the experimental data. The sequence of Gibbs energies of different systems is: G Zr-Al-Ni-Cu Zr-Al-Ni Zr-Al-Cu Cu-Al-Ni . To Zr-Al-Cu, Ni-Al-Cu and Zr-Ni-Al, the lowest Gibbs energy locates in the composition range of X Zr 0.39-0.61, X Al = 0.38-0.61; X Ni = 0.39-0.61, X Al = 0.38-0.60 and X Zr = 0.32-0.67, X Al = 0.32-0.66, respectively. And to the Zr-Ni-Al-Cu system with 66.67% Zr, the lowest Gibbs energy is obtained in the region of X Al = 0.63-0.80, X Ni = 0.14-0.24

Brazing characteristics of a Zr-Ti-Cu-Fe eutectic alloy filler metal for Zircaloy-4

Science.gov (United States)

Lee, Jung G.; Lim, C. H.; Kim, K. H.; Park, S. S.; Lee, M. K.; Rhee, C. K.

2013-10-01

A Zr-Ti-Cu-Fe quaternary eutectic alloy was employed as a new Be-free brazing filler metal for Zircaloy-4 to supersede physically vapor-deposited Be coatings used conventionally with several disadvantages. The quaternary eutectic composition of Zr58Ti16Cu10Fe16 (at.%) showing a low melting temperature range from 832 °C to 853 °C was designed by a partial substitution of Zr with Ti based on a Zr-Cu-Fe ternary eutectic system. By applying an alloy ribbon with the determined composition, a highly reliable joint was obtained with a homogeneous formation of predominantly grown α-Zr phases owing to a complete isothermal solidification, exhibiting strength higher than that of Zircaloy-4. The homogenization of the joint was rate-controlled by the diffusion of the filler elements (Ti, Cu, and Fe) into the Zircaloy-4 base metal, and the detrimental segregation of the Zr2Fe phase in the central zone was completely eliminated by an isothermal holding at a brazing temperature of 920 °C for 10 min.

Effects of the Buffer Layers on the Adhesion and Antimicrobial Properties of the Amorphous ZrAlNiCuSi Films

Science.gov (United States)

Chiang, Pai-Tsung; Chen, Guo-Ju; Jian, Sheng-Rui; Shih, Yung-Hui

2011-06-01

To extend the practical applications of the bulk metallic glasses (BMGs), the preparation of the metallic glass coatings on various substrates becomes an important research issue. Among the interfacial properties of the coatings, the adhesion between films and substrates is the most crucial. In this study, amorphous Zr61Al7.5Ni10Cu17.5Si4 (ZrAlNiCuSi) thin films were deposited on SUS304 stainless steel at various sputtering powers by DC sputtering. According to the scratch tests, the introduction of the Cr and Ti buffer layers effectively improves the adhesion between the amorphous thin films and substrate without changing the surface properties, such as roughness and morphology. The antimicrobial results show that the biological activities of these microbes, except Acinetobacter baumannii, are effectively suppressed during the test period.

Effect of rolling deformation on the microstructure of bulk Cu60Zr20Ti20 metallic glass and its crystallization

DEFF Research Database (Denmark)

Cao, Q.P.; Li, J.F.; Zhou, Y.H.

2006-01-01

Bulk Cu60Zr20Ti20 metallic glass has been rolled at room temperature (RT) and cryogenic temperature (CIF) up to 97% in thickness reduction, and the dependences of microstructure on the strain and temperature have been investigated. It is revealed that as the deformation proceeds below a critical...... thickness reduction, which is 87% at RT and 89% at CT, only the shear band density and the free-volume content increase, whereas the thermal stability of the deformed glass remains unchanged. Deformation above the critical thickness reduction results in phase separation plus nanocrystallization at RT...

Internal friction in cold-rolled metallic glasses Cu50Ti50 and Ni78Si8B14

International Nuclear Information System (INIS)

Zolotukhin, I.V.; Khonik, V.A.; Ryabtseva, T.N.; Belyavskii, V.I.

1989-01-01

The influence of cold rolling on the low temperature (30 to 300 K) internal friction of metallic glasses Cu 50 Ti 50 and Ni 78 Si 8 B 14 is investigated. It is shown that cold rolling of both metallic glasses up to 2 to 6% results in the appearance of a high relaxation damping peak around 260 to 280 K. The internal friction background below the peak shows a strong amplitude dependence. In highly predeformed specimens (∼ 16%) the internal friction peak is absent. Electron irradiation (2 MeV, 10 19 cm -2 ) leads to the suppression of the deformation-induced internal friction peak. The results are interpreted in the framework of the dislocation models of plastic flow of metallic glasses. (author)

An interatomic potential for studying CuZr bulk metallic glasses

DEFF Research Database (Denmark)

Paduraru, Anca; Kenoufi, Abdel; Bailey, Nicholas

2007-01-01

-scale deformation events and may furthermore involve localization through formation of shear bands. In this paper, an Effective Medium Theory (EMT) potential optimized for modeling the mechanical and thermodynamic properties of CuZr bulk metallic glass is studied. The late transition metals crystallizing in close......The mechanical properties of BMGs are remarkably different from the ones of ordinary metallic alloys due to the atomic level disorder in the glassy state. Unlike crystalline materials plastic deformation in metallic glasses cannot be caused by lattice defects but takes place through atomic...

On the Potential of Bulk Metallic Glasses for Dental Implantology: Case Study on Ti40Zr10Cu36Pd14.

Science.gov (United States)

Liens, Alethea; Etiemble, Aurélien; Rivory, Pascaline; Balvay, Sandra; Pelletier, Jean-Marc; Cardinal, Sandrine; Fabrègue, Damien; Kato, Hidemi; Steyer, Philippe; Munhoz, Tais; Adrien, Jerome; Courtois, Nicolas; Hartmann, Daniel J; Chevalier, Jérôme

2018-02-06

Ti 40 Zr 10 Cu 36 Pd 14 Bulk Metallic Glass (BMG) appears very attractive for future biomedical applications thanks to its high glass forming ability, the absence of toxic elements such as Ni, Al or Be and its good mechanical properties. For the first time, a complete and exhaustive characterization of a unique batch of this glassy alloy was performed, together with ISO standard mechanical tests on machined implant-abutment assemblies. The results were compared to the benchmark Ti-6Al-4V ELI (Extra-Low-Interstitial) to assess its potential in dental implantology. The thermal stability, corrosion and sterilization resistance, cytocompatibility and mechanical properties were measured on samples with a simple geometry, but also on implant-abutment assemblies' prototypes. Results show that the glassy alloy exhibits a quite high thermal stability, with a temperature range of 38 °C between the glass transition and crystallization, a compressive strength of 2 GPa, a certain plastic deformation (0.7%), a hardness of 5.5 GPa and a toughness of 56 MPa.√m. Moreover, the alloy shows a relatively lower Young's modulus (96 GPa) than the Ti-6Al-4V alloy (110-115 GPa), which is beneficial to limit bone stress shielding. The BMG shows a satisfactory cytocompatibility, a high resistance to sterilization and a good corrosion resistance (corrosion potential of -0.07 V/SCE and corrosion current density of 6.0 nA/cm²), which may ensure its use as a biomaterial. Tests on dental implants reveal a load to failure 1.5-times higher than that of Ti-6Al-4V and a comparable fatigue limit. Moreover, implants could be machined and sandblasted by methods usually conducted for titanium implants, without significant degradation of their amorphous nature. All these properties place this metallic glass among a promising class of materials for mechanically-challenging applications such as dental implants.

On the Potential of Bulk Metallic Glasses for Dental Implantology: Case Study on Ti40Zr10Cu36Pd14

Directory of Open Access Journals (Sweden)

Alethea Liens

2018-02-01

Full Text Available Ti40Zr10Cu36Pd14 Bulk Metallic Glass (BMG appears very attractive for future biomedical applications thanks to its high glass forming ability, the absence of toxic elements such as Ni, Al or Be and its good mechanical properties. For the first time, a complete and exhaustive characterization of a unique batch of this glassy alloy was performed, together with ISO standard mechanical tests on machined implant-abutment assemblies. The results were compared to the benchmark Ti-6Al-4V ELI (Extra-Low-Interstitial to assess its potential in dental implantology. The thermal stability, corrosion and sterilization resistance, cytocompatibility and mechanical properties were measured on samples with a simple geometry, but also on implant-abutment assemblies’ prototypes. Results show that the glassy alloy exhibits a quite high thermal stability, with a temperature range of 38 °C between the glass transition and crystallization, a compressive strength of 2 GPa, a certain plastic deformation (0.7%, a hardness of 5.5 GPa and a toughness of 56 MPa.√m. Moreover, the alloy shows a relatively lower Young’s modulus (96 GPa than the Ti-6Al-4V alloy (110–115 GPa, which is beneficial to limit bone stress shielding. The BMG shows a satisfactory cytocompatibility, a high resistance to sterilization and a good corrosion resistance (corrosion potential of −0.07 V/SCE and corrosion current density of 6.0 nA/cm2, which may ensure its use as a biomaterial. Tests on dental implants reveal a load to failure 1.5-times higher than that of Ti-6Al-4V and a comparable fatigue limit. Moreover, implants could be machined and sandblasted by methods usually conducted for titanium implants, without significant degradation of their amorphous nature. All these properties place this metallic glass among a promising class of materials for mechanically-challenging applications such as dental implants.

Analysis of Pressure-Volume Relationship for Bulk Metallic Glasses

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H. K. Rai

2008-01-01

Full Text Available Relationship between compression (V/V0 and pressure have been studied for five bulk metallic glasses (BMGs viz. Zr41Ti14Cu12.5Ni10Be22.5, Zr41Ti14Cu12.5Ni9Be22.5C1, Zr48Nb8Cu12Fe8Be24, (Zr0.59Ti0.06Cu0.22Ni0.1385.7Al14.3 and SiO2.TiO2 in the compression ranges of V/V0 =1.00 to V/V0 = 0.10. Six forms of equation of state reported in the literature have been used in the present study to calculate pressure corresponding to different values of compressions. The comparison of graph plotted between the logarithms of calculated value of pressure to logarithm of calculated value of compression (V/V0 reveals that the agreement of Brennan-Stacey equation of state (EOS and Poirier-Tarantolla equation of state are not good. It has been found that the assumptions, on which these equations are based, do not satisfy well in case of given BMGs.

Amorphous Ti-Zr

International Nuclear Information System (INIS)

Rabinkin, A.; Liebermann, H.; Pounds, S.; Taylor, T.

1991-01-01

This paper is the first report on processing, properties and potential application of amorphous titanium/zirconium-base alloys produced in the form of a good quality continuous and ductile ribbon having up to 12.5 mm width. To date, the majority of titanium brazing is accomplished using cooper and aluminum-base brazing filler metals. The brazements produced with these filler metals have rather low (∼300 degrees C) service temperature, thus impeding progress in aircraft and other technologies and industries. The attempt to develop a generation of high temperature brazing filler metals was made in the late sixties-early seventies studies in detail were a large number of Ti-, Zr-Ti-Zr, Ti-V and Zr-V-Ti based alloys. The majority of these alloys has copper and nickel as melting temperature depressants. The presence of nickel and copper converts them into eutectic alloys having [Ti(Zr)] [Cu(Ni)], intermetallic phases as major structural constituents. This, in turn, results in high alloy brittleness and poor, if any, processability by means of conventional, i.e. melting-ingot casting-deformation technology. In spite of good wettability and high joint strength achieved in dozens of promising alloys, only Ti-15Cu-15Ni is now widely used as a brazing filler metal for high service temperature. Up until now this material could not be produced as a homogeneous foil and is instead applied as a clad strip consisting of three separate metallic layers

Investigation of Partially Crystalline Zr77Ni23 Metallic Glass

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Amra Salčinović Fetić

2016-08-01

Full Text Available This paper presents the results of an extensive research of partially crystalline Zr77Ni23 metallic glass (indicated numbers refer to atomic percentages. The partially crystalline Zr77Ni23 samples were prepared by melt-spinning using a device constructed in the Metal Physics Laboratory, Faculty of Science in Sarajevo. XRD pattern shows crystalline peaks which correspond to an orthorhombic structure of Zr3Ni superimposed on an amorphous pattern. Homogeneity and chemical composition were investigated using scanning electron microscopy (SEM and energy-dispersive X-ray spectroscopy (EDX. Crystallization was studied by differential scanning calorimetry (DSC. DSC analysis indicated a simple thermally activated process. Overall activation energy of the crystallization was calculated using Kissinger's model for nonisothermal process and compared with those given by the Augis-Bennett model. By monitoring of the electrical resistance in the temperature range 80 – 270 K a small and negative thermal coefficient of electrical resistance was observed. This means that electrical resistance varies slightly with temperature and it makes this metallic glass suitable for application in electronic circuits for which this property is an important requirement.

Devitrification kinetics and phase selection mechanisms in Cu-Zr metallic glasses

Energy Technology Data Exchange (ETDEWEB)

Kalay, Ilkay [Iowa State Univ., Ames, IA (United States)

2010-01-01

Metallic glasses have been a promising class of materials since their discovery in the 1960s. Indeed, remarkable chemical, mechanical and physical properties have attracted considerable attention, and several excellent reviews are available. Moreover, the special group of glass forming alloys known as the bulk metallic glasses (BMG) become amorphous solids even at relatively low cooling rates, allowing them to be cast in large cross sections, opening the scope of potential applications to include bulk forms and net shape structural applications. Recent studies have been reported for new bulk metallic glasses produced with lower cooling rates, from 0.1 to several hundred K/s. Some of the application products of BMGs include sporting goods, high performance springs and medical devices. Several rapid solidification techniques, including melt-spinning, atomization and surface melting have been developed to produce amorphous alloys. The aim of all these methods is to solidify the liquid phase rapidly enough to suppress the nucleation and growth of crystalline phases. Furthermore, the production of amorphous/crystalline composite (ACC) materials by partial crystallization of amorphous precursor has recently given rise to materials that provide better mechanical and magnetic properties than the monolithic amorphous or crystalline alloys. In addition, these advances illustrate the broad untapped potential of using the glassy state as an intermediate stage in the processing of new materials and nanostructures. These advances underlie the necessity of investigations on prediction and control of phase stability and microstructural dynamics during both solidification and devitrification processes. This research presented in this dissertation is mainly focused on Cu-Zr and Cu-Zr-Al alloy systems. The Cu-Zr binary system has high glass forming ability in a wide compositional range (35-70 at.% Cu). Thereby, Cu-Zr based alloys have attracted much attention according to fundamental

Vitrification and determination of the crystallization time scales of the bulk-metallic-glass-forming liquid Zr58.5Nb2.8Cu15.6Ni12.8Al10.3

International Nuclear Information System (INIS)

Hays, C. C.; Schroers, J.; Johnson, W. L.; Rathz, T. J.; Hyers, R. W.; Rogers, J. R.; Robinson, M. B.

2001-01-01

The crystallization kinetics of Zr 58.5 Nb 2.8 Cu 15.6 Ni 12.8 Al 10.3 were studied in an electrostatic levitation (ESL) apparatus. The measured critical cooling rate is 1.75 K/s. Zr 58.5 Nb 2.8 Cu 15.6 Ni 12.8 Al 10.3 is the first bulk-metallic-glass-forming liquid that does not contain beryllium to be vitrified by purely radiative cooling in the ESL. Furthermore, the sluggish crystallization kinetics enable the determination of the time-temperature-transformation (TTT) diagram between the liquidus and the glass transition temperatures. The shortest time to reach crystallization in an isothermal experiment; i.e., the nose of the TTT diagram is 32 s. The nose of the TTT diagram is at 900 K and positioned about 200 K below the liquidus temperature

Promising Ta-Ti-Zr-Si metallic glass coating without cytotoxic elements for bio-implant applications

Science.gov (United States)

Lai, J. J.; Lin, Y. S.; Chang, C. H.; Wei, T. Y.; Huang, J. C.; Liao, Z. X.; Lin, C. H.; Chen, C. H.

2018-01-01

Tantalum (Ta) is considered as one of the most promising metal due to its high corrosion resistance, excellent biocompatibility and cell adhesion/in-growth capabilities. Although there are some researches exploring the biomedical aspects of Ta and Ta based alloys, systematic characterizations of newly developed Ta-based metallic glasses in bio-implant applications is still lacking. This study employs sputtering approach to produced thin-film Ti-based metallic glasses due to the high melting temperature of Ta (3020 °C). Two fully amorphous Ta-based metallic glasses composed of Ta57Ti17Zr15Si11 and Ta75Ti10Zr8Si7 are produced and experimentally characterized in terms of their mechanical properties, bio-corrosion properties, surface hydrophilic characteristics, and in-vitro cell viability and cells attachment tests. Compare to conventional pure Ti and Ta metals, the developed Ta-based metallic glasses exhibit higher hardness and lower modulus which are better match to the mechanical properties of bone. MTS assay results show that Ta-based metallic glasses show comparable cell viability and cell attachment rate compared to that of pure Ti and Ta surface in a 72 h in-vitro test.

An interatomic potential for studying CuZr bulk metallic glasses

International Nuclear Information System (INIS)

Paduraru, A.; Kenoufi, A.; Bailey, N.P.; Schioetz, J.

2007-01-01

Glass forming ability has been found in only a small number of binary alloys, one being CuZr. In order to simulate this glass, we fitted an interatomic potential within Effective Medium Theory (EMT). For this purpose we use basic properties of the B2 crystal structure as calculated from Density Functional Theory (DFT) or obtained from experiments. We then performed Molecular Dynamics (MD) simulations of the cooling process and studied the thermodynamics and structure of CuZr glass. We find that the potential gives a good description of the CuZr glass, with a glass transition temperature and elastic constants close to the experimental values. The local atomic order, as witnessed by the radial distribution function, is also consistent with similar experimental data. (Abstract Copyright [2007], Wiley Periodicals, Inc.)

Effect of Ge addition on mechanical properties and fracture behavior of Cu-Zr-Al bulk metallic glass

International Nuclear Information System (INIS)

Malekan, M.; Shabestari, S.G.; Gholamipour, R.; Seyedein, S.H.

2009-01-01

Effect of the addition of a small amount of Ge on mechanical properties and fracture behavior of Cu 50 Zr 43 Al 7 (at.%) bulk metallic glass were studied. The Cu 50 Zr 43 Al 7 alloy has a surprising glass-forming ability (GFA), and the glassy rods up to 4 mm in diameter can be formed. Partial addition of Ge causes the crystalline phases precipitate in the glassy matrix of (Cu 50 Zr 43 Al 7 ) 100-x Ge x (x = 0, 1, 2) rods with a diameter of 4 mm. In uniaxial compression, Cu 50 Zr 43 Al 7 bulk metallic glass exhibit high strength of 1692 MPa and very limited plasticity of 0.05%. When Ge increases from 0 to 2 at.%, the strength decreases, but plastic strain increases about 2.5%. Fracture surface and shear bands of samples were investigated by scanning electron microscopy (SEM).

Phonon dispersion of metallic glass CuZr{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Nakashima, S [Department of Condensed Matter Chemistry and Physics, Graduate School of Sciences, Kyushu University, 4-2-1 Ropponmatsu, Chuo-ku, Fukuoka 810-8560 (Japan); Kawakita, Y [Department of Physics, Faculty of Sciences, Kyushu University, 4-2-1 Ropponmatsu, Chuo-ku, Fukuoka 810-8560 (Japan); Otomo, T [Japan Proton Accelerator Research Complex, High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba 305-0801, Japan (Japan); Suenaga, R [Department of Condensed Matter Chemistry and Physics, Graduate School of Sciences, Kyushu University, 4-2-1 Ropponmatsu, Chuo-ku, Fukuoka 810-8560 (Japan); Baron, A Q R [Materials Dynamics Laboratory, Harima RIKEN, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); Tsutsui, S [Japan Synchrotron Radiation Research Institute (JASRI, SPring-8), 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan (Japan); Kohara, S [Japan Synchrotron Radiation Research Institute (JASRI, SPring-8), 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan (Japan); Takeda, S [Department of Physics, Faculty of Sciences, Kyushu University, 4-2-1 Ropponmatsu, Chuo-ku, Fukuoka 810-8560 (Japan); Itoh, K [Research Reactor Institute, Kyoto University, Kumatori-cho, Sennnan-gun, Osaka 590-0494 (Japan); Kato, H [Institute for Material Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Fukunaga, T [Research Reactor Institute, Kyoto University, Kumatori-cho, Sennnan-gun, Osaka 590-0494 (Japan); Hasegawa, M [Department of Materials, Physics and Energy Engineering, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8603 (Japan)

2007-12-15

Collective dynamics of metallic glass CuZr{sub 2} has been studied in the first pseudo Brillouin zone using high-resolution inelastic X-ray scattering. Acoustic-like longitudinal propagating excitations were observed and the dispersion relation was determined. In addition of longitudinal mode, transverse mode with half excitation energy contributes to medium energy-transfer region.

Direct observation of shear–induced nanocrystal attachment and coalescence in CuZr-based metallic glasses: TEM investigation

International Nuclear Information System (INIS)

Hajlaoui, K.; Alrasheedi, Nashmi H.; Yavari, A.R.

2016-01-01

In-situ tensile straining tests were performed in a transmission electron microscope (TEM) to analyse the deformation processes in CuZr-based metallic glasses and to directly observe the phase transformation occurrence. We report evidence of shear induced coalescence of nanocrystals in the vicinity of deformed regions. Nanocrystals grow in shear bands, come into contact, being attached and progressively coalesce under applied shear stress. - Highlights: • In-situ tensile straining test in TEM was investigated on CuZr-Based metallic glass. • Strain induces nanocrystallization and subsequent attachment and coalescence of nanocrystals. • The coalescence of nanocrystals compensates strain softening in metallic glasses.

Zr61Ti2Cu25Al12 metallic glass for potential use in dental implants: Biocompatibility assessment by in vitro cellular responses

International Nuclear Information System (INIS)

Li, Jing; Shi, Ling-ling; Zhu, Zhen-dong; He, Qiang; Ai, Hong-jun; Xu, Jian

2013-01-01

In comparison with titanium and its alloys, Zr 61 Ti 2 Cu 25 Al 12 (ZT1) bulk metallic glass (BMG) manifests a good combination of high strength, high fracture toughness and lower Young's modulus. To examine its biocompatibility required for potential use in dental implants, this BMG was used as a cell growth subtract for three types of cell lines, L929 fibroblasts, human umbilical vein endothelial cells (HUVEC), and osteoblast-like MG63 cells. For a comparison, these cell lines were in parallel cultured and grown also on commercially pure titanium (CP-Ti) and Ti6–Al4–V alloy (Ti64). Cellular responses on the three metals, including adhesion, morphology and viability, were characterized using the SEM visualization and CCK-8 assay. Furthermore, real-time RT-PCR was used to measure the activity of integrin β, alkaline phosphatase (ALP) and type I collagen (COL I) in adherent MG63 cells. As indicated, in all cases of three cell lines, no significant differences in the initial attachment and viability/proliferation were found between ZT1, CP-Ti, and Ti64 until 5 d of incubation period. It means that the biocompatibility in cellular response for ZT1 BMG is comparable to Ti and its alloys. For gene expression of integrin β, ALP and COL I, mRNA level from osteoblast cells grown on ZT1 substrates is significantly higher than that on the CP-Ti and Ti64. It suggests that the adhesion and differentiation of osteoblasts grown on ZT1 are even superior to those on the CP-Ti and Ti64 alloy, then promoting bone formation. The good biocompatibility of ZT1 BMG is associated with the formation of zirconium oxide layer on the surface and good corrosion-resistance in physiological environment. Quantitative analysis of Real-time PCR for MG63 cells cultured on Zr 61 Ti 2 Cu 25 Al 12 BMG, CP-Ti, and Ti64 as well as plastic as a control at several incubation periods. Relative amounts of (a) integrin β, (b) ALP, and (c) COL I (*p < 0.05). Highlights: ► Cellular response to ZrTiCu

Discontinuities of Plastic Deformation in Metallic Glasses with Different Glass Forming Ability

Science.gov (United States)

Hurakova, Maria; Csach, Kornel; Miskuf, Jozef; Jurikova, Alena; Demcak, Stefan; Ocelik, Vaclav; Hosson, Jeff Th. M. De

The metallic ribbons Fe40Ni40B20, Cu47Ti35Zr11Ni6Si1 and Zr65Cu17.5Ni10Al7.5 with different microhardness and glass forming ability were studied at different loading rates from 0.05 to 100 mN/s. We describe in details the differences in elemental discontinuities on the loading curves for the studied alloys. It was found that the discontinuities began at a certain local deformation independently on the macroscopic mechanical properties of a ribbon. More developed discontinuities at higher deformations are created for the materials with lower microhardness and so lower strength.

The fundamental structural factor in determining the glass-forming ability and mechanical behavior in the Cu-Zr metallic glasses

International Nuclear Information System (INIS)

Sha, Z.D.; Feng, Y.P.; Li, Y.

2011-01-01

Research highlights: → A weak but significant hump in trend of the coordinate number and density was observed, respectively. → Our findings indicate our simulation is more accurate to describe the atomic structure of Cu-Zr MGs. The composition-structure-properties correlation was established. → And the effective structural unit for this correlation is the Cu-centered full icosahedra. - Abstract: Using the large-scale atomic/molecular massively parallel simulator, the quantitative composition-structure-properties (including glass-forming ability (GFA) and mechanical behavior) correlations in the Cu-Zr metallic glasses were established. The atomic-level origin of these correlations was tracked down. It was found that the Cu-centered full icosahedron is the microscopic factor that fundamentally influences both GFA and mechanical behavior. Our findings have implications for understanding the nature, forming ability and properties of metallic glasses, and for searching novel metallic glasses with unique functional properties.

Nanostructure analysis of friction welded Pd-Ni-P/Pd-Cu-Ni-P metallic glass interface

International Nuclear Information System (INIS)

Ohkubo, T.; Shoji, S.; Kawamura, Y.; Hono, K.

2005-01-01

Friction welded Pd 40 Ni 40 P 20 /Pd 40 Cu 30 Ni 10 P 20 metallic glass interface has been characterized by energy filtering transmission electron microscopy. The interface is fully amorphous with a gradual compositional change of Cu and Ni in the range of 30 nm. By annealing above T g , the interdiffusion of Cu and Ni progressed in the supercooled liquid region, and the crystallization occurred from the Pd 40 Ni 40 P 20 glass

Combinatorial development of antibacterial Zr-Cu-Al-Ag thin film metallic glasses.

Science.gov (United States)

Liu, Yanhui; Padmanabhan, Jagannath; Cheung, Bettina; Liu, Jingbei; Chen, Zheng; Scanley, B Ellen; Wesolowski, Donna; Pressley, Mariyah; Broadbridge, Christine C; Altman, Sidney; Schwarz, Udo D; Kyriakides, Themis R; Schroers, Jan

2016-05-27

Metallic alloys are normally composed of multiple constituent elements in order to achieve integration of a plurality of properties required in technological applications. However, conventional alloy development paradigm, by sequential trial-and-error approach, requires completely unrelated strategies to optimize compositions out of a vast phase space, making alloy development time consuming and labor intensive. Here, we challenge the conventional paradigm by proposing a combinatorial strategy that enables parallel screening of a multitude of alloys. Utilizing a typical metallic glass forming alloy system Zr-Cu-Al-Ag as an example, we demonstrate how glass formation and antibacterial activity, two unrelated properties, can be simultaneously characterized and the optimal composition can be efficiently identified. We found that in the Zr-Cu-Al-Ag alloy system fully glassy phase can be obtained in a wide compositional range by co-sputtering, and antibacterial activity is strongly dependent on alloy compositions. Our results indicate that antibacterial activity is sensitive to Cu and Ag while essentially remains unchanged within a wide range of Zr and Al. The proposed strategy not only facilitates development of high-performing alloys, but also provides a tool to unveil the composition dependence of properties in a highly parallel fashion, which helps the development of new materials by design.

Resistance to He{sup 2+} induced irradiation damage in metallic glass Zr{sub 64}Cu{sub 17.8}Ni{sub 10.7}Al{sub 7.5}

Energy Technology Data Exchange (ETDEWEB)

Wang, Bin [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Dalian University of Technology, Ministry of Education, Dalian 116024 (China); Mei, Xianxiu, E-mail: xxmei@dlut.edu.cn [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Dalian University of Technology, Ministry of Education, Dalian 116024 (China); Zhang, Hongran; Hou, Wenjing; Wang, Younian [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Dalian University of Technology, Ministry of Education, Dalian 116024 (China); Wang, Zhiguang [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Dong, Chuang [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Dalian University of Technology, Ministry of Education, Dalian 116024 (China)

2014-01-15

Graphical abstract: This paper used TEM for the analysis of the microstructure, helium bubble distribution and helium bubble growth process of Zr-based metallic glass after the irradiation at maximum fluence. Fig. a shows the cross-sectional TEM sample morphology image of Zr-based metallic glass. It could be observed that a large number of helium bubbles were distributed on the topmost surface of Zr-based metallic glass (Zone A in Fig.a). The helium bubbles on the surface were mostly round, except for a small number of irregular-shape bubbles, with the sizes ranging from several nanometers to several tens of nanometers. The helium bubble diameter became gradually smaller downwardly from Zone A. As shown in Fig.a, the helium bubble size was small within the range of 0.3–1.2 μm below the surface (Zone B), and a large number of helium bubbles with a diameter of several nanometers were uniformly distributed in the area close to Zone A and Zone C; as shown in Fig.b, a helium bubble layer appeared within the range of 1.2–1.5 μm (Zone C) away from the surface, and it was found that the helium bubble size was larger in the vicinity of 1.3 μm away from the surface. Fig.b shows the atom vacancy distribution curves in Zr-based metallic glass before and after the helium ion irradiation obtained through SRIM program simulation. It could be observed that vacancy concentration peaks appeared at the ion range of 1.2 μm, and a large number of vacancies were concentrated at the end of the range. The vacancies of the sample were very easy to capture helium atoms and were conducive to the formation and growth of helium bubbles. -- Highlights: • Metallic glass could maintain amorphous state at different irradiation fluences. • A damage layer appeared in Zr{sub 64}Cu{sub 17.8}Ni{sub 10.7}Al{sub 7.5} at a fluence of 2 × 10{sup 18} ions/cm{sup 2}. • Peeling and delamination appeared numerously in W at a fluence of 1 × 10{sup 18} ions/cm{sup 2}. • Lots of helium bubbles

The influence of Zr substitution for Nb on the corrosion behaviors of the Ni-Nb-Zr bulk metallic glasses

Science.gov (United States)

Li, DengKe; Zhu, ZhengWang; Zhang, HaiFeng; Wang, AiMin; Hu, ZhuangQi

2012-12-01

The influence of Zr content on corrosion behaviors of the Ni61.5Nb38.5- x Zr x ( x=1, 3, 5, 7, 9 at.%) bulk metallic glasses (BMGs) in 1 M HCl aqueous solution was investigated by potentiodynamic polarization measurements and X-ray photo-electron spectroscopy (XPS). It was found that these BMG alloys possess superior corrosion resistance, that is, with large passive region of about 1.5 V and low passive current density (as low as 0.05 Am-2 for Ni61.5Nb31.5Zr7). XPS analysis indicates that the high corrosion resistance is attributed to the formation of Nb- and Zr-enriched surface films formed in the aggressive acid solution. The Zr substitution for Nb effectively reduces the Ni content, particularly the metallic state Ni content in the surface films, which depresses the electrical conduction of the surface films and reduces the passive current density, thus leading to the enhancement of the corrosion resistance of these Ni-Nb-Zr BMGs. These alloys may potentially be useful for engineering applications.

Strong-Superstrong Transition in Glass Transition of Metallic Glass

International Nuclear Information System (INIS)

Dan, Wang; Hong-Yan, Peng; Xiao-Yu, Xu; Bao-Ling, Chen; Chun-Lei, Wu; Min-Hua, Sun

2010-01-01

Dynamic fragility of bulk metallic glass (BMG) of Zr 64 Cu 16 Ni 10 Al 10 alloy is studied by three-point beam bending methods. The fragility parameter mfor Zr 64 Cu 16 Ni 10 Al 10 BMG is calculated to be 24.5 at high temperature, which means that the liquid is a 'strong' liquid, while to be 13.4 at low temperature which means that the liquid is a 'super-strong' liquid. The dynamical behavior of Zr 64 Cu 16 Ni 10 Al 10 BMG in the supercooled region undergoes a strong to super-strong transition. To our knowledge, it is the first time that a strong-to-superstrong transition is found in the metallic glass. Using small angle x-ray scattering experiments, we find that this transition is assumed to be related to a phase separation process in supercooled liquid. (condensed matter: structure, mechanical and thermal properties)

Microstructure of bonding interface for resistance welding of Zr-based metallic glass sheets

International Nuclear Information System (INIS)

Kuroda, Toshio; Ikeuchi, Kenji; Shimada, Masahiro; Kobayashi, Akira; Kimura, Hisamichi; Inoue, Akihisa

2009-01-01

Resistance welding of Zr 55 Cu 30 Al 10 Ni 5 metallic glass sheets was investigated at 723 K in a supercooled liquid region. The welding time was changed from 5 s to 20 s at 723 K. The joint interface of the metallic glass was no defect and no crack. X-ray diffraction technique of the bonding interface of specimens was performed. The specimens showed halo patterns showing existence of only glassy phase, when the welding time was 5 s and 10 s. X-ray diffraction patterns of specimen bonded for 20 s showed crystalline peaks with halo patterns for the welding for 20 s. The crystalline phase at the bonding interface was small. Transmission electron micrograph at the bonding interface showed nanostructures of NiZr 2 and Al 5 Ni 3 Zr 2 . (author)

Microstructure and Mechanical Characterization of a Dissimilar Friction-Stir-Welded CuCrZr/CuNiCrSi Butt Joint

Directory of Open Access Journals (Sweden)

Youqing Sun

2018-05-01

Full Text Available Dissimilar CuNiCrSi and CuCrZr butt joints were successfully frictionstirwelded at constant welding speed of 150 mm/min and rotational speed of 1400 rpm with the CuCrZr alloy or the CuNiCrSi alloy located on the advancing side (AS. The microstructure and mechanical properties of joints were investigated. When the CuCrZr alloy was located on the AS, the area of retreating material in the nugget zone was a little bigger. The Cr solute-rich particles were found in the nugget zone on CuCrZr side (CuCrZr-NZ while a larger density of solute-rich particles identified as the concentration of Cr and Si element was found in the nugget zone on CuNiCrSi side (CuNiCrSi-NZ. The Cr precipitates and δ-Ni2Si precipitates were found in the base metal on CuNiCrSi side (CuNiCrSi-BM but only Cr precipitates can be observed in the base metal on CuCrZr side (CuCrZr-BM. Precipitates were totally dissolved into Cu matrix in both CuCrZr-NZ and CuNiCrSi-NZ, which led to a sharp decrease in both micro-hardness and tensile strength from BM to NZ. When the CuNiCrSi was located on the AS, the tensile testing results showed the fracture occurred at the CuCrZr-NZ, while the fracture was found at the mixed zone of CuNiCrSi-NZ and CuCrZr-NZ for the other case.

Molecular dynamics simulations of the structure evolutions of Cu-Zr metallic glasses under irradiation

Energy Technology Data Exchange (ETDEWEB)

Lang, Lin [College of Materials Science and Engineering, Hunan University, Changsha 410082 (China); Department of Applied Physics, School of Physics and Electronics, Hunan University, Changsha 410082 (China); Tian, Zean; Xiao, Shifang [Department of Applied Physics, School of Physics and Electronics, Hunan University, Changsha 410082 (China); Deng, Huiqiu, E-mail: hqdeng@hnu.edu.cn [Department of Applied Physics, School of Physics and Electronics, Hunan University, Changsha 410082 (China); Ao, Bingyun [Science and Technology on Surface Physics and Chemistry Laboratory, Mianyang 621907 (China); Chen, Piheng, E-mail: chenpiheng@caep.cn [Science and Technology on Surface Physics and Chemistry Laboratory, Mianyang 621907 (China); Hu, Wangyu [College of Materials Science and Engineering, Hunan University, Changsha 410082 (China)

2017-02-15

Highlights: • The structural evolution of Cu{sub 64.5}Zr{sub 35.5} MG under irradiation was studied. • The structure clusters were analyzed using the LSCA method. • Most of these radiation damages have been self-recovered quickly. - Abstract: Molecular dynamics simulations have been performed to investigate the structural evolution of Cu{sub 64.5}Zr{sub 35.5} metallic glasses under irradiation. The largest standard cluster analysis (LSCA) method was used to quantify the microstructure within the collision cascade regions. It is found that the majority of clusters within the collision cascade regions are full and defective icosahedrons. Not only the smaller structures (common neighbor subcluster) but also primary clusters greatly changed during the collision cascades; while most of these radiation damages self-recover quickly in the following quench states. These findings indicate the Cu-Zr metallic glasses have excellent irradiation-resistance properties.

Effect of MoSi2 Content on Dry Sliding Tribological Properties of Zr-Based Bulk Metallic Glass Composites

Science.gov (United States)

Liu, Longfei; Yang, Jun

2017-12-01

Zr55Cu30Al10Ni5 bulk metallic glass and its composites were prepared by suction casting into a copper mold. The effect of MoSi2 content on the tribological behavior of Zr55Cu30Al10Ni5 BMG was studied by using a high-speed reciprocating friction and wear tester. The results indicate that the friction coefficient and wear resistance of the BMGs can be improved by a certain amount of crystalline phase induced by MoSi2 content from 1 to 3% and deteriorated with MoSi2 content of 4%. The wear mechanism of both the metallic glass and its composite is abrasive wear. The mechanism of crystalline phase-dependent tribological properties of the composite was discussed based on the wear track and mechanical properties in the present work. The wear behavior of Zr55Cu30Al10Ni5 BMG and its composite indicates that a good combination of the toughness and the hardness can make the composite be well wear resistant.

Strong work-hardening behavior induced by the solid solution strengthening of dendrites in TiZr-based bulk metallic glass matrix composites

Energy Technology Data Exchange (ETDEWEB)

Ma, D.Q. [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Jiao, W.T. [College of Education, Hebei Normal University of Science and Technology, Qinhuangdao 066004 (China); Zhang, Y.F. [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Hebei Vocational and Technical College of Building Materials, Qinhuangdao 066004 (China); Wang, B.A.; Li, J.; Zhang, X.Y. [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Ma, M.Z., E-mail: mz550509@ysu.edu.cn [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Liu, R.P. [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China)

2015-03-05

Highlights: • Hardness of dendrite of TiZr-based BMGMCs increases. • Strong work-hardening behavior is obtained after solid solution strengthening. • Lattice distortions of dendrite suffering from rapid cooling are detected. - Abstract: A series of TiZr-based bulk metallic glass matrix composites (BMGMCs) with distinguished mechanical properties are successfully fabricated by adding different volume fractions of Ta (Ti{sub 38.8}Zr{sub 28.8}Cu{sub 6.2}Be{sub 16.2}Nb{sub 10} as the basic composition, denoted as Ta{sub 0.0}–Ta{sub 8.0}). Along with the growth of precipitated phase, typical dendritic morphology is fully developed in the TiZr-based BMGMCs of Ta{sub 8.0}. Energy-dispersive spectrometry analysis of the dendrites and glass matrix indicates that the metallic elements of Nb and Ta should preferentially form solid solution into dendrites. The chaotic structure of high-temperature precipitate phase is trapped down by the rapid cooling of the copper-mould. The detected lattice distortions in the dendrites are attributed to the strong solid solution strengthening of the metallic elements of Ti, Zr, Nb, and Ta. These lattice distortions increase the resistance of the dislocation motion and pin the dislocations, thus the strength and hardness of dendrite increase. Dendrites create a strong barrier for the shear band propagation and generate multiple shear bands after solid solution strengthening, thereby providing the TiZr-based BMGMCs with greatly improved capacity to sustain plastic deformation and resistance to brittle fracture. Thus, the TiZr-based BMGMCs possess distinguished work-hardening capability. Among these TiZr-based BMGMCs, the sample Ta{sub 0.5} possesses the largest plastic strain (ε{sub p}) at 20.3% and ultimate strength (σ{sub max}) of 2613 MPa during compressive loading. In addition, the sample of Ta{sub 0.5} exhibits work-hardening up to an ultrahigh tensile strength of 1680 MPa during the tensile process, and then progressively

Effect of isothermal annealing on the compressive strength of a ZrAlNiCuNb metallic glass

International Nuclear Information System (INIS)

Song Min; He Yuehui

2011-01-01

Research highlights: → Only structural relaxation happens during annealing at the temperature below T g . → Nanocrystallization happens during annealing at the temperature above T g . → The compressive strength increases with annealing time up to 20 min. → The compressive strength decreases with annealing time after 20 min. - Abstract: The effects of isothermal annealing on the microstructures and compressive strength of a Zr 56 Al 10.9 Ni 4.6 Cu 27.8 Nb 0.7 bulk metallic glass (BMG) have been studied using X-ray diffraction, scanning electron microscopy and compression tests. It has been shown that only structural relaxation happens during annealing at the temperature below T g (glass transition temperature), while both structural relaxation and nanocrystallization happen during annealing at the temperature above T g . Compression tests indicated that the strength of the BMG increases with annealing time at 437 deg. C up to 20 min, after which the strength starts to decrease. The strength evolution of the BMG with the annealing time is due to combined effects of the variations of the free volume and nanocrystals.

The evolution of interface microstructure in a ZrO2/Ag-Cu-Al-Ti system

International Nuclear Information System (INIS)

Lee, Youngmin; Yu, Jin

1993-01-01

Among ceramic/metal (C/M) joining technologies, the active filler metal method has been studied extensively due to the simple brazing process and excellent joint strength. Active metal elements, typically Ti, are intentionally added to braze alloys to enhance the formation of reaction products between the ceramic and the braze metal at the C/M interface. In the brazing of Al 2 O 3 with the Ag-Cu-Ti filler metal, reaction products such as γ-TiO, Cu 2 (Ti, Al) 4 O, Ti 3 (Cu 0.76 Al 0.18 Sn 0.06 ) 3 O were found, while products such as Ti 5 Si 3 and TiN formed in the brazing of Si 3 N 4 . The presence of reaction layers at the C/M interface influences the interface strength in a complex way. In Cu/Al 2 O 3 , Co/Al 2 O 3 , Ni/Al 2 O 3 , and Cu/diamond systems, maxima of joint strength were observed at some intermediate Ti addition, while the flexural strength decreased substantially with the thickening of the TiO layer in a ZrO 2 /Ag-Cu-Sn-Ti system. Thus, composition of the braze alloy (particularly, the content of the active metal), process conditions such as brazing temperature and time, microstructure and mechanical properties of reaction products at the C/M interfaces, interfacial chemistry, and residual stress are primary factors to be studied in order to understand the strengths of the C/M interfaces systematically. In the present and the following papers, evolutions of interfacial microstructures at various brazing conditions, and corresponding interface strengths are reported, respectively, for a ZrO 2 /Ag-Cu-Al-Ti system

Investigation of Mechanical Properties and Plastic Deformation Behavior of (Ti45Cu40Zr10Ni5100−xAlx Metallic Glasses by Nanoindentation

Directory of Open Access Journals (Sweden)

Lanping Huang

2014-01-01

Full Text Available The effect of Al addition on mechanical properties and plastic deformation behavior of (Ti45Cu40Zr10Ni5100−xAlx (x = 0, 2, 4, 6 and 8 amorphous alloy ribbons have been investigated by nanoindentation. The hardness and elastic modulus do not simply increase with the increase of Al content. The alloy with 8 at.% Al exhibits the highest hardness and elastic modulus. The serrations or pop-in events are strongly dependent on the loading rate and alloy composition.

Caltech Center for Structural and Amorphous Metals

Science.gov (United States)

2005-05-10

Flores, D. Suh, R. Howell, P. Asoka -Kumar, P.A. Sterne, and R. H. Dauskardt, "Flow and Fracture of Bulk Metallic Glass Alloys and Their Composites...Behavior of Zr-Ti-Cu-Ni-Be Bulk Metallic Glass Alloys," Materials Transactions, JIM, 42 [4], 638-641, 2001. K. M. Flores, D. Suh, P. Asoka -Kumar, P.A...Materials Research, 17[5], 1153-1161, 2002. D. Suh, P. Asoka -Kumar and R. H. Dauskardt, "The Effects of Hydrogen on Viscoelastic Relaxation in Zr-Ti-Ni-Cu

Unusual glass-forming ability induced by changes in the local atomic structure in Ti-based bulk metallic glass

International Nuclear Information System (INIS)

Kim, Y C; Chang, H J; Kim, D H; Kim, W T; Cha, P R

2007-01-01

The effect of partial replacement of Cu by Be in Ti 50 Cu 32 Ni 15 Sn 3 alloy on the thermal properties, structure, and forming ability of an amorphous phase were investigated by differential scanning calorimetry (DSC), x-ray diffraction (XRD), extended x-ray absorption fine structure (EXAFS), and high-resolution transmission electron microscopy (HRTEM). Ti 50 Cu 25 Ni 15 Sn 3 Be 7 alloy shows enhanced glass-forming ability, enabling one to fabricate a fully amorphous bulk metallic glass sample 2 mm in diameter by injection casting. With the replacement, the supercooled liquid region ΔT x (= T x -T g , where T x is the crystallization temperature and T g is the glass transition temperature) decreased from 73 to 45 K and the reduced glass transition temperature T rg (= T g /T 1 , where T 1 is the liquidus temperature) increased from 0.53 to 0.57. The amorphous Ti 50 Cu 25 Ni 15 Sn 3 Be 7 phase showed a formation of short-range-ordered clusters 1-2 nm in size, which is attributed to the strong interaction between Ti and Be. The results show that ΔT x can be used as a thermal parameter reflecting the glass-forming ability of the alloy only when the phase formed during crystallization is the same as the phase competing with the glass transition during solidification

Superhydrophobic Zr-based metallic glass surface with high adhesive force

Science.gov (United States)

Li, Ning; Xia, Ting; Heng, Liping; Liu, Lin

2013-06-01

Micro/nano hierarchical structures were constructed on Zr35Ti30Be26.75Cu8.25 metallic glass surface by silicon moulding and subsequently chemical etching. The as-formed surface exhibited both superhydrophobicity and high adhesive force towards water. The superhydrophobicity is rationalized based on the modified Cassie-Baxter model [A. B. D. Cassie and S. Baxter, Trans. Faraday Soc. 40, 546 (1944)]. The origin of the robust adhesion is described in terms of intermolecular capillary forces. The present results not only provide a method to fabricate superhydrophobic metallic glasses surface but also explore an important industrial application as dry adhesives and transport of liquid microdroplets.

Cooling rate dependence of simulated Cu{sub 64.5}Zr{sub 35.5} metallic glass structure

Energy Technology Data Exchange (ETDEWEB)

Ryltsev, R. E. [Institute of Metallurgy, Ural Branch of Russian Academy of Sciences, 101 Amundsen Str., 620016 Ekaterinburg (Russian Federation); Ural Federal University, 19 Mira Str., 620002 Ekaterinburg (Russian Federation); L.D. Landau Institute for Theoretical Physics, Russian Academy of Sciences, 2 Kosygina Str., 119334 Moscow (Russian Federation); Klumov, B. A. [L.D. Landau Institute for Theoretical Physics, Russian Academy of Sciences, 2 Kosygina Str., 119334 Moscow (Russian Federation); Aix-Marseille-Université, CNRS, Laboratoire PIIM, UMR 7345, 13397 Marseille Cedex 20 (France); High Temperature Institute, Russian Academy of Sciences, 13/2 Izhorskaya Str., 125412 Moscow (Russian Federation); Chtchelkatchev, N. M. [Institute of Metallurgy, Ural Branch of Russian Academy of Sciences, 101 Amundsen Str., 620016 Ekaterinburg (Russian Federation); L.D. Landau Institute for Theoretical Physics, Russian Academy of Sciences, 2 Kosygina Str., 119334 Moscow (Russian Federation); Moscow Institute of Physics and Technology, 9 Institutskiy Per., Dolgoprudny, 141700 Moscow Region (Russian Federation); All-Russia Research Institute of Automatics, 22 Sushchevskaya, 127055 Moscow (Russian Federation); Shunyaev, K. Yu. [Institute of Metallurgy, Ural Branch of Russian Academy of Sciences, 101 Amundsen Str., 620016 Ekaterinburg (Russian Federation); Ural Federal University, 19 Mira Str., 620002 Ekaterinburg (Russian Federation)

2016-07-21

Using molecular dynamics simulations with embedded atom model potential, we study structural evolution of Cu{sub 64.5}Zr{sub 35.5} alloy during the cooling in a wide range of cooling rates γ ∈ (1.5 ⋅ 10{sup 9}, 10{sup 13}) K/s. Investigating short- and medium-range orders, we show that the structure of Cu{sub 64.5}Zr{sub 35.5} metallic glass essentially depends on cooling rate. In particular, a decrease of the cooling rate leads to an increase of abundances of both the icosahedral-like clusters and Frank-Kasper Z16 polyhedra. The amounts of these clusters in the glassy state drastically increase at the γ{sub min} = 1.5 ⋅ 10{sup 9} K/s. Analysing the structure of the glass at γ{sub min}, we observe the formation of nano-sized crystalline grain of Cu{sub 2}Zr intermetallic compound with the structure of Cu{sub 2}Mg Laves phase. The structure of this compound is isomorphous with that for Cu{sub 5}Zr intermetallic compound. Both crystal lattices consist of two types of clusters: Cu-centered 13-atom icosahedral-like cluster and Zr-centered 17-atom Frank-Kasper polyhedron Z16. That suggests the same structural motifs for the metallic glass and intermetallic compounds of Cu–Zr system and explains the drastic increase of the abundances of these clusters observed at γ{sub min}.

A statistical physics consideration about the strength of small size metallic glass pillars

NARCIS (Netherlands)

Chen, Changqiang; Pei, Yutao; De Hosson, Jeff Th. M.; Skrotzki, W; Oertel, CG; Biermann, H; Heilmaier, M

2010-01-01

We have fabricated micro-/nano-pillars of a Zr-based metallic glass, Zr(50)Ti(16.5)Cu(15)Ni(18.5), with pillar tip diameters ranging from similar to 750 nm to similar to 110 nm. These pillars were mechanically tested quantitatively in-situ in a Transmission Electron Microscope (TEM). Due to a slight

ZrCuAl Bulk Metallic Glass spall induced by laser shock

Science.gov (United States)

Jodar, Benjamin; Loison, Didier; Yokoyama, Yoshihiko; Lescoute, Emilien; Berthe, Laurent; Sangleboeuf, Jean-Christophe

2017-06-01

To face High Velocity Impacts, the aerospace industry is always seeking for innovative materials usable as debris shielding components. Bulk Metallic Glasses (BMG) revealed interesting mechanical properties in case of static and quasi-static loading conditions: high elasticity, high tenacity, low density and high fracture threshold... The department of Mechanics and Glass of the Institut of Physics Rennes conducted on the ELFIE facility, laser shock experiments to study the behavior of a ternary ZrCuAl BMG under high strain rate, up-to fragmentation process. On the one hand, in-situ diagnostics were used to measure ejection velocities with PDV and debris morphologies were observed by Shadowgraphy. On the other hand, spalled areas (dimensions and features) were characterized through post-mortem analysis (optical observations, profilometry and SEM). These results are compared to experimental and numerical data on the crystalline forms of the ZrCuAl basic compounds.

Flow and Fracture of Bulk Metallic Glass Alloys and their Composites

International Nuclear Information System (INIS)

Flores, K M; Suh, D; Howell, R; Asoka-Kumar, P; Dauskardt, R H

2001-01-01

The fracture and plastic deformation mechanisms of a Zr-Ti-Ni-Cu-Be bulk metallic glass and a composite utilizing a crystalline reinforcement phase are reviewed. The relationship between stress state, free volume and shear band formation are discussed. Positron annihilation techniques were used to confirm the predicted increase in free volume after plastic straining. Strain localization and failure were examined for a wide range of stress states. Finally, methods for toughening metallic glasses are considered. Significant increases in toughness are demonstrated for a composite bulk metallic glass containing a ductile second phase which stabilizes shear band formation and distributes plastic deformation

Formation of quasicrystals and amorphous-to-quasicrystalline phase transformation kinetics in Zr65Al7.5Ni10Cu7.5Ag10 metallic glass under pressure

DEFF Research Database (Denmark)

Jiang, Jianzhong; Zhuang, Yanxin; Rasmussen, Helge Kildahl

2001-01-01

The effect of pressure on the formation of quasicrystals and the amorphous-to-quasicrystalline phase transformation kinetics in the supercooled liquid region for a Zr65Al7.5Ni10Cu7.5Ag10 metallic glass have been investigated by in situ high-pressure and high-temperature nonisothermal and isothermal...... of quasicrystals decrease, Atomic mobility is important for the formation of quasicrystals from the metallic glass whereas the relationship of the crystallization temperature vs pressure for the transition from the quasicrystalline state to intermetallic compounds may mainly depend on the thermodynamic potential...... energy barrier. To study the amorphous-to-quasicrystalline phase transformation kinetics in the metallic glass, relative volume fractions of the transferred quasicrystalline phase as a function of annealing time, obtained at 663, 673, 683, and 693 K, have been analyzed in details using 14 nucleation...

Glass forming ability and mechanical properties of Zr50Cu42Al8 bulk metallic glass

International Nuclear Information System (INIS)

Xia, L; Chan, K C; Wang, G; Liu, L

2008-01-01

In this work, we report that Zr 50 Cu 42 Al 8 bulk metallic glass (BMG) exhibits excellent glass forming ability and mechanical properties. Zr 50 Cu 42 Al 8 glassy rods with a diameter of 3 mm were prepared using conventional copper mould suction casting. The glassy rod exhibits a modulus of about 115 GPa and a fracture strength of about 2 GPa, and, as compared with other large-scale BMGs, it has excellent room-temperature plasticity of up to 20% under compression. The fracture mechanism of the rod was investigated by microstructural investigations, and it was found that the large plasticity of the as-cast rod is closely related to the in situ formation of nano-crystalline particles embedded in the amorphous matrix.

Corrosion behavior and pitting susceptibility of in-situ Ti-based metallic glass matrix composites in 3.5 wt.% NaCl solutions

Science.gov (United States)

Xu, K. K.; Lan, A. D.; Yang, H. J.; Han, P. D.; Qiao, J. W.

2017-11-01

The Ti62Zr12V13Cu4Be9, Ti58Zr16V10Cu4Be12, Ti46Zr20V12Cu5Be17, and Ti40Zr24V12Cu5Be19 metallic glass matrix composites (MGMCs) were prepared by copper mould casting. The corrosion resistance and the pitting susceptibility of Ti-based MGMCs were tested on their cross-sectional areas in 3.5 wt.% NaCl solutions by potentiodynamic polarization measurements. The composites with lower Ti contents (Ti40Zr24V12Cu5Be19 and Ti46Zr20V12Cu5Be17) exhibit a low resistance to the chloride induced pitting and local corrosion. The preferential dissolution of amorphous matrix is explained by the high chemical reactivity of beryllium element compared to that of stable dendrites and by the detected lower Ti and V contents. However, fairly good passivity was found in the composite with higher Ti contents (Ti62Zr12V13Cu4Be9). XPS measurements revealed that protective Ti-enriched oxide film was formed on the composite surface, additionally, lower content of beryllium element in amorphous matrix hinder the selective corrosion of amorphous matrix. The assessment of experimental observation leads to a proposed corrosion mechanism involving selective dissolution of amorphous matrix and chloride induced pitting process.

Characterization of mechanically alloyed Ti-based bulk metallic glass composites containing carbon nanotubes

Energy Technology Data Exchange (ETDEWEB)

Hsu, C.F. [Institute of Materials Engineering, National Taiwan Ocean University, No. 2, Beining Road, Keelung (China); Lin, H.M. [Department of Materials Engineering, Tatung University, No.40, Sec. 3, Jhongshan N. Rd. Jhongshan District, Taipei 104 Taiwan (China); Lee, P.Y.

2008-11-15

This study explored the feasibility of preparing CNT/Ti{sub 50}Cu{sub 28}Ni{sub 15}Sn{sub 7} bulk metallic glass (BMG) composites though powder metallurgy route. The CNT/Ti{sub 50}Cu{sub 28}Ni{sub 15}Sn{sub 7} BMG composites were obtained by consolidating the 8h mechanically alloyed composite powders by vacuum hot pressing process. A significant increase in hardness (9.34 GPa) and fracture strength (1937 MPa) was achieved for the Ti{sub 50}Cu{sub 28}Ni{sub 15}Sn{sub 7} BMG composites containing 12 vol. % CNT. (Abstract Copyright [2008], Wiley Periodicals, Inc.)

Thermal stability and mechanical properties of the TiCuZrPd glasses with 10, 14 and 20 at.% Pd

International Nuclear Information System (INIS)

Sypien, Anna; Czeppe, Tomasz; Garzel, Grzegorz; Litynska-Dobrzynska, Lidia; Latuch, Jerzy; Chinh, N.Q.

2014-01-01

Highlights: • Metallic glasses Ti 40 Zr 10 Cu 40−x Pd 10+x with x = 0, 4 and 10, were investigated. • The DSC, TMA, Hv 10 and depth-sensing indentation method were applied. • The TMA was performed on ribbons in the modulated constant load tensile mode. • Thermal evolution of the materials ductility was identified by dL/dTL 0 function. • High macro- and nanohardness increasing after crystallization were determined. - Abstract: Metallic glasses of the composition Ti 40 Zr 10 Cu 40−x Pd 10+x with x = 0, 4 and 10, were investigated from the point of view of the thermal stability, crystallization and hardness. The samples in the form of melt spun ribbons and rods 2.8 mm in diameter, were characterized by differential scanning calorimetry (DSC), Thermo-Mechanical Analysis (TMA), macro-Vickers hardness (MHv 10 ) and depth-sensing indentation measurements. The TMA experiments were performed on ribbons in the modulated constant load tensile mode. The processes of relaxation, glass transition and crystallization were observed with DSC and transmission electron microscopy (TEM). The relative length changes rates as a function of temperature (dL/dTL 0 ) showed influence of the thermal stability of the amorphous phase on the materials ductility. High ductility was available in the wide range of temperature including primary crystallization range. Vickers-macrohardness of BMG was about 5500 MPa and nanohardness was about 9300 MPa, increasing after crystallization completion by about 18%. At small nanoindentation rates deformed amorphous phase revealed local plastic instability resulting from the shear bands formation

Mechanism of abnormally slow crystal growth of CuZr alloy

International Nuclear Information System (INIS)

Yan, X. Q.; Lü, Y. J.

2015-01-01

Crystal growth of the glass-forming CuZr alloy is shown to be abnormally slow, which suggests a new method to identify the good glass-forming alloys. The crystal growth of elemental Cu, Pd and binary NiAl, CuZr alloys is systematically studied with the aid of molecular dynamics simulations. The temperature dependence of the growth velocity indicates the different growth mechanisms between the elemental and the alloy systems. The high-speed growth featuring the elemental metals is dominated by the non-activated collision between liquid-like atoms and interface, and the low-speed growth for NiAl and CuZr is determined by the diffusion across the interface. We find that, in contrast to Cu, Pd, and NiAl, a strong stress layering arisen from the density and the local order layering forms in front of the liquid-crystal interface of CuZr alloy, which causes a slow diffusion zone. The formation of the slow diffusion zone suppresses the interface moving, resulting in much small growth velocity of CuZr alloy. We provide a direct evidence of this explanation by applying the compressive stress normal to the interface. The compression is shown to boost the stress layering in CuZr significantly, correspondingly enhancing the slow diffusion zone, and eventually slowing down the crystal growth of CuZr alloy immediately. In contrast, the growth of Cu, Pd, and NiAl is increased by the compression because the low diffusion zones in them are never well developed

Welding of CuZr-based metallic glasses on air

International Nuclear Information System (INIS)

Batalha, W.; Gargarella, P.; Kiminami, C.S.

2016-01-01

Metallic glass alloys have been studied aiming at its exceptional mechanical properties. This alloys processing's requires high cooling rates, which diminishes the sample's size. There by welding these samples without the loss of amorphous structure is a good alternative. The DEMa group has developed a technique based on Joule effect heating. By applying pressure and electric current, reaching temperatures of super cold liquids (the temperature between crystallizing and vitric transition), the vitric metal has it’s viscosity reduced and sample binding occur. The objective of this paper was to weld samples of cylindrical geometry of 2 and 3 mm in diameter and 4 mm in length of the compositions Cu46Zr42Al7Y5 and (Cu47Zr45Al8)98Y2. The process was done using 2 copper electrodes under(over) argon flux. The samples were later analysed by microscopy, differential scanning calorimetry and X ray diffraction. The results showed that this kind of welding process is possible since crystal formation on the welding region did not occur and there were no faults like cracks or porosity. (author)

Oxidation feature and diffusion mechanism of Zr-based metallic glasses near the glass transition point

Science.gov (United States)

Hu, Zheng; Lei, Xianqi; Wang, Yang; Zhang, Kun

2018-03-01

The oxidation behaviors of as-cast, pre-deformed, and crystallized Zr47.9Ti0.3Ni3.1Cu39.3Al9.4 metallic glasses (MGs) were studied near the glass transition point. The oxidation kinetics of the crystallized MGs followed a parabolic-rate law, and the as-cast and pre-deformed MGs exerted a typical two-stage behavior above the glass transition temperature (T g). Most interesting, pre-deformed treatment can significantly improve the oxidation rate of MGs, as the initial oxidation appeared earlier than for the as-cast MGs, and was accompanied by much thicker oxide scale. The EDS and XPS results showed that the metal Al acted as the preferred scavenger that absorbed intrinsic oxygen in the near-surface region of as-cast MGs. However, a homogeneous mixed layer without Al was observed in the pre-deformed MGs. We speculated the accelerated diffusion of other elements in the MGs was due to the local increase in the free volume and significant shear-induced dilation of the local structure. The results from this study demonstrate that MGs exhibit controllable atomic diffusion during the oxidation process, which can facilitate use in super-cooled liquid region applications.

Viscoelasticity of metallic, polymeric and oxide glasses

Energy Technology Data Exchange (ETDEWEB)

Pelletier, J.M. [GEMPPM, INSA Lyon, Bat. B. Pascal, 69621 Villeurbanne (France)]. E-mail: Jean-marc.Pelletier@insa-lyon.fr; Gauthier, C. [GEMPPM, INSA Lyon, Bat. B. Pascal, 69621 Villeurbanne (France); Munch, E. [GEMPPM, INSA Lyon, Bat. B. Pascal, 69621 Villeurbanne (France)

2006-12-20

Present work addresses on mechanical spectroscopy experiments performed on bulk metallic glasses (Zr-Ti-Cu-Ni-Be alloys, Mg-Y-Cu alloys), on oxide glasses (SiO{sub 2}-Na{sub 2}O-CaO) and on amorphous polymers (polyethylene terephtalate (PET), nitrile butadiene rubber (NBR), etc.). It appears that whatever the nature of the chemical bonding involved in the material, we observe strong relaxation effects in an intermediate temperature range, near the glass transition temperature. In addition, when crystallization occurs in the initially amorphous material, similar evolution is observed in all the materials. A method is proposed to properly separate elastic, viscoelastic and viscoplastic contributions to the deformation. Finally a physical model is given to describe these viscoelastic phenomena.

Molecular Dynamics Simulation of Structural Characterization of Elastic and Inelastic Deformation in ZrCu Metallic Glasses

Directory of Open Access Journals (Sweden)

Shidong Feng

2014-01-01

Full Text Available The nanoscopic deformation behaviors in a ZrCu metallic glass model during loading-unloading process under uniaxial compression have been analyzed on the basis of the molecular dynamics (MD. The reversible degree of shear origin zones (SOZs is used as the structural indicator to distinguish the elastic deformation and inelastic deformation of ZrCu metallic glass at the atomic level. We find that the formation of SOZs is reversible at the elastic stage but irreversible at the inelastic stage during the loading and unloading processes. At the inelastic stage, the full-icosahedra fraction in SOZs is quickly reduced with increased strain and the decreasing process is also irreversible during the unloading processes.

Comparison of mechanical behavior between bulk and ribbon Cu-based metallic glasses

International Nuclear Information System (INIS)

Jiang, W.H.; Liu, F.X.; Wang, Y.D.; Zhang, H.F.; Choo, H.; Liaw, P.K.

2006-01-01

As-cast bulk and as-spun ribbon Cu 60 Zr 30 Ti 10 metallic glasses were characterized using differential-scanning calorimetry and instrumented nanoindentation. Two alloys show a significant difference in the amount of free volume, which is attributed to the difference in a cooling rate, while exhibiting a similar serrated plastic flow. Atomic-force-microscopy observations demonstrate the pile-ups containing shear bands around the indents in both alloys. The as-cast bulk alloy has higher hardness and elastic modulus than the as-spun ribbon alloy. The difference in the strengths of two alloys may be related to the different amount of free volume. The strength seems to be more sensitive to a cooling rate during solidification than the plastic-flow behavior in the Cu 60 Zr 30 Ti 10

The responses of endothelial cells to Zr{sub 61}Ti{sub 2}Cu{sub 25}Al{sub 12} metallic glass in vitro and in vivo

Energy Technology Data Exchange (ETDEWEB)

Li, Jing, E-mail: monkeys0109@sina.com; Ai, Hong-jun

2014-07-01

The goal of this study was to evaluate the biocompatibility of newly developed Zr{sub 61}Ti{sub 2}Cu{sub 25}Al{sub 12} metallic glass (denoted ZT1) and its parallel material, commercially pure titanium (CP-Ti), as dental implants. To this end, we evaluated their cytotoxicity in vitro using human umbilical vein endothelial cells (HUVECs) and in vivo by performing an oral mucosa irritation test in hamsters. Specifically, cytotoxicity was determined in HUVECs by evaluating their cell morphology using scanning electron microscopy (SEM) and their cell viability using CCK-8 assays. Moreover, we examined the mRNA levels of vascular endothelial growth factor and von Willebrand factor by quantitative PCR (qPCR). In the early stages of proliferation and differentiation, no differences were observed between HUVECs inoculated on ZT1 compared to those on CP-Ti. However, in the later stages of proliferation and differentiation, the HUVECs inoculated on ZT1 were significantly better than the cells cultured on CP-Ti. In the oral mucosa irritation test, we sutured sample discs into the cheek pouch of hamsters. After 2, 3, and 4 weeks, we harvested the corresponding mucosal tissues, stained them with hematoxylin and eosin, obtained blood samples for biochemical analysis, and finally, observed the topography of the sample discs by SEM. Immunohistochemistry and hematology analyses showed no differences in the biocompatibility of ZT1 and CP-Ti, and neither of these compounds caused irritation of the mucosa. In addition, SEM images showed that no pitting occurred on the sample discs. Together, these data indicate that ZT1 may be a good candidate for dental implants and should be further studied. - Graphical abstract: The results of blood analysis. (a) WBC, (b) Mon %, (c) Neu %, and (d) Eos %. - Highlights: • We used HUVECs to evaluate the cytotoxicity of Zr{sub 61}Ti{sub 2}Cu{sub 25}Al{sub 12} BMG. • We are the first to evaluate Zr{sub 61}Ti{sub 2}Cu{sub 25}Al{sub 12} BMG using an

Dynamic strength behavior of a Zr-based bulk metallic glass under shock loading

International Nuclear Information System (INIS)

Yu Yu-Ying; Xi Feng; Dai Cheng-Da; Cai Ling-Cang; Tan Ye; Li Xue-Mei; Wu Qiang; Tan Hua

2015-01-01

Dynamic strength behavior of Zr 51 Ti 5 Ni 10 Cu 25 Al 9 bulk metallic glass (BMG) up to 66 GPa was investigated in a series of plate impact shock-release and shock-reload experiments. Particle velocity profiles measured at the sample/LiF window interface were used to estimate the shear stress, shear modulus, and yield stress in shocked BMG. Beyond confirming the previously reported strain-softening of shear stress during the shock loading process for BMGs, it is also shown that the softened Zr-BMG still has a high shear modulus and can support large yield stress when released or reloaded from the shocked state, and both the shear modulus and the yield stress appear as strain-hardening behaviors. The work provides a much clearer picture of the strength behavior of BMGs under shock loading, which is useful to comprehensively understand the plastic deformation mechanisms of BMGs. (paper)

The effect of Nb addition on mechanical properties, corrosion behavior, and metal-ion release of ZrAlCuNi bulk metallic glasses in artificial body fluid.

Science.gov (United States)

Qiu, C L; Liu, L; Sun, M; Zhang, S M

2005-12-15

Bulk metallic glasses (BMGs) of Zr(65 - x)Nb(x)- Cu(17.5)Ni(10)Al(7.5) with Nb = 0, 2, and 5 at % were prepared by copper mold casting. Compression tests reveal that the two BMGs containing Nb exhibited superior strength and plasticity to the base alloy. The corrosion behavior of the alloys obtained was investigated in artificial body fluid by electrochemical measurements. It was found that the addition of Nb significantly enhanced the corrosion resistance of the Zr-based BMG, as indicated by a remarkable increase in corrosion potential and pitting potential. XPS analysis revealed that the passive film formed after anodic polarization was enriched in aluminum oxide and depleted in phosphate ions for the BMGs containing Nb, which accounts for the improvement of corrosion resistance. On the other hand, metal-ion release of different BMGs were determined in PPb (ng/mL) level with inductively coupled plasma mass spectrometry (ICP-MS) after being immersed in artificial body fluid at 37 degrees C for 20 days. It was found that the addition of Nb considerably reduced the ion release of all kinds of metals of the base system. This is probably attributed to the promoting effect of Nb on a rapid formation of highly protective film.

Zr{sub 61}Ti{sub 2}Cu{sub 25}Al{sub 12} metallic glass for potential use in dental implants: Biocompatibility assessment by in vitro cellular responses

Energy Technology Data Exchange (ETDEWEB)

Li, Jing [School of Stomatology, China Medical University, 117 Nanjing North Sreet, Shenyang, 110002 (China); Shi, Ling-ling; Zhu, Zhen-dong; He, Qiang [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang, 110016 (China); Ai, Hong-jun, E-mail: aih0620@yahoo.com.cn [School of Stomatology, China Medical University, 117 Nanjing North Sreet, Shenyang, 110002 (China); Xu, Jian, E-mail: jianxu@imr.ac.cn [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang, 110016 (China)

2013-05-01

In comparison with titanium and its alloys, Zr{sub 61}Ti{sub 2}Cu{sub 25}Al{sub 12} (ZT1) bulk metallic glass (BMG) manifests a good combination of high strength, high fracture toughness and lower Young's modulus. To examine its biocompatibility required for potential use in dental implants, this BMG was used as a cell growth subtract for three types of cell lines, L929 fibroblasts, human umbilical vein endothelial cells (HUVEC), and osteoblast-like MG63 cells. For a comparison, these cell lines were in parallel cultured and grown also on commercially pure titanium (CP-Ti) and Ti6–Al4–V alloy (Ti64). Cellular responses on the three metals, including adhesion, morphology and viability, were characterized using the SEM visualization and CCK-8 assay. Furthermore, real-time RT-PCR was used to measure the activity of integrin β, alkaline phosphatase (ALP) and type I collagen (COL I) in adherent MG63 cells. As indicated, in all cases of three cell lines, no significant differences in the initial attachment and viability/proliferation were found between ZT1, CP-Ti, and Ti64 until 5 d of incubation period. It means that the biocompatibility in cellular response for ZT1 BMG is comparable to Ti and its alloys. For gene expression of integrin β, ALP and COL I, mRNA level from osteoblast cells grown on ZT1 substrates is significantly higher than that on the CP-Ti and Ti64. It suggests that the adhesion and differentiation of osteoblasts grown on ZT1 are even superior to those on the CP-Ti and Ti64 alloy, then promoting bone formation. The good biocompatibility of ZT1 BMG is associated with the formation of zirconium oxide layer on the surface and good corrosion-resistance in physiological environment. Quantitative analysis of Real-time PCR for MG63 cells cultured on Zr{sub 61}Ti{sub 2}Cu{sub 25}Al{sub 12} BMG, CP-Ti, and Ti64 as well as plastic as a control at several incubation periods. Relative amounts of (a) integrin β, (b) ALP, and (c) COL I (*p < 0

Thermal stability and mechanical properties of the TiCuZrPd glasses with 10, 14 and 20 at.% Pd

Energy Technology Data Exchange (ETDEWEB)

Sypien, Anna, E-mail: a.sypien@imim.pl [Institute of Metallurgy and Materials Science PAS, Reymonta 25 St., 30-059 Kraków (Poland); Czeppe, Tomasz, E-mail: t.czeppe@imim.pl [Institute of Metallurgy and Materials Science PAS, Reymonta 25 St., 30-059 Kraków (Poland); Garzel, Grzegorz, E-mail: g.garzel@imim.pl [Institute of Metallurgy and Materials Science PAS, Reymonta 25 St., 30-059 Kraków (Poland); Litynska-Dobrzynska, Lidia, E-mail: l.litynsk@imim.pl [Institute of Metallurgy and Materials Science PAS, Reymonta 25 St., 30-059 Kraków (Poland); Latuch, Jerzy, E-mail: jlatuch@inmat.pw.edu.pl [Warsaw University of Technology, Warsaw (Poland); Chinh, N.Q., E-mail: chinh@metal.elte.hu [Eötvös University, Budapest (Hungary)

2014-12-05

Highlights: • Metallic glasses Ti{sub 40}Zr{sub 10}Cu{sub 40−x}Pd{sub 10+x} with x = 0, 4 and 10, were investigated. • The DSC, TMA, Hv{sub 10} and depth-sensing indentation method were applied. • The TMA was performed on ribbons in the modulated constant load tensile mode. • Thermal evolution of the materials ductility was identified by dL/dTL{sub 0} function. • High macro- and nanohardness increasing after crystallization were determined. - Abstract: Metallic glasses of the composition Ti{sub 40}Zr{sub 10}Cu{sub 40−x}Pd{sub 10+x} with x = 0, 4 and 10, were investigated from the point of view of the thermal stability, crystallization and hardness. The samples in the form of melt spun ribbons and rods 2.8 mm in diameter, were characterized by differential scanning calorimetry (DSC), Thermo-Mechanical Analysis (TMA), macro-Vickers hardness (MHv{sub 10}) and depth-sensing indentation measurements. The TMA experiments were performed on ribbons in the modulated constant load tensile mode. The processes of relaxation, glass transition and crystallization were observed with DSC and transmission electron microscopy (TEM). The relative length changes rates as a function of temperature (dL/dTL{sub 0}) showed influence of the thermal stability of the amorphous phase on the materials ductility. High ductility was available in the wide range of temperature including primary crystallization range. Vickers-macrohardness of BMG was about 5500 MPa and nanohardness was about 9300 MPa, increasing after crystallization completion by about 18%. At small nanoindentation rates deformed amorphous phase revealed local plastic instability resulting from the shear bands formation.

Tribological behavior of the kinetic sprayed Ni59Ti16Zr20Si2Sn3 bulk metallic glass

International Nuclear Information System (INIS)

Choi, Hanshin; Jo, Hyungho; An, Kyoungjun; Yoon, Sanghoon; Lee, Changhee

2007-01-01

Gas atomized amorphous Ni 59 Ti 16 Zr 20 Si 2 Sn 3 feedstock particles were fed into warm gas dynamics and they were successfully overlaid onto the mild steel substrate. Through the X-ray diffractometry and differential scanning calorimetry, it could be confirmed that thermally activated processes such as crystallization and in-flight particle oxidation were effectively suppressed during the modified kinetic spraying process. In order to evaluate the tribological behavior of the kinetic sprayed Ni 59 Ti 16 Zr 20 Si 2 Sn 3 BMG coating, a partially crystallized coating and a fully crystallized coating were prepared by isothermal heat treatments

Application of Zr/Ti-Pic in the adsorption process of Cu(II), Co(II) and Ni(II) using adsorption physico-chemical models and thermodynamics of the process; Aplicacao de Zr/Ti-PILC no processo de adsorcao de Cu(II), Co(II) e Ni(II) utilizando modelos fisico-quimicos de adsorcao e termodinamica do processo

Energy Technology Data Exchange (ETDEWEB)

Guerra, Denis Lima; Airoldi, Claudio [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Inst. de Quimica. Dept. de Quimica Inorganica]. E-mail: dlguerra@iqm.unicamp.br; Lemos, Vanda Porpino; Angelica, Romulo Simoes [Universidade Federal do Para (UFPa), Belem (Brazil); Viana, Rubia Ribeiro [Universidade Federal do Mato Grosso (UFMT), Cuiaba (Brazil). Inst. de Ciencias Exatas e da Terra. Dept. de Recursos Minerais

2008-07-01

The aim of this investigation is to study how Zr/Ti-Pic adsorbs metals. The physico-chemical proprieties of Zr/Ti-Pic have been optimized with pillarization processes and Cu(II), Ni(II) and Co(II) adsorption from aqueous solution has been carried out, with maximum adsorption values of 8.85, 8.30 and 7.78 x-1 mmol g{sup -1}, respectively. The Langmuir, Freundlich and Temkin adsorption isotherm models have been applied to fit the experimental data with a linear regression process. The energetic effect caused by metal interaction was determined through calorimetric titration at the solid-liquid interface and gave a net thermal effect that enabled the calculation of the exothermic values and the equilibrium constant. (author)

Preparation of Zr50Al15-xNi10Cu25Yx amorphous powders by mechanical alloying and thermodynamic calculation

International Nuclear Information System (INIS)

Long, Woyun; Li, Jing; Lu, Anxian

2013-01-01

Amorphous Zr 50 Al 15-x Ni 10 Cu 25 Y x powders were fabricated by mechanical alloying at a low rotation speed from commercial pure element powders. The beneficial effect of Al partially substituted by Y in Zr 50 Al 15 Ni 10 Cu 25 on glass-forming ability was investigated. The as-milled powders were characterized by X-ray diffraction and transmission electron microscopy. The results show that partial substitution of Al by Y can improve the glass-forming ability of Zr 50 Al 15 Ni 10 Cu 25 Y alloy. Thermodynamic calculation of equivalent free energy shows that Zr 50 Al 13.8 Ni 10 Cu 25 Y 1.2 alloy has the highest glass-forming ability, which is in good agreement with the report of orthogonal experiments. (author)

NiTiCu/AlN/NiTiCu shape memory thin film heterostructures for vibration damping in MEMS

Energy Technology Data Exchange (ETDEWEB)

Kaur, Navjot; Kaur, Davinder, E-mail: dkaurfph@iitr.ernet.in

2014-03-25

Highlights: • Fabrication of NiTiCu/AlN/NiTiCu heterostructure using dc/rf magnetron sputtering. • Exhibits highest hardness (38 GPa) and elastic modulus (187 GPa). • Enhanced dissipation of mechanical energy (E{sub d} = 5.7 N J). • High damping capacity (0.052) and figure of merit (∼0.62). • Can be applied for vibration damping in MEMS. -- Abstract: Shape memory alloy (NiTiCu) thin films coupled with piezoelectric AlN layer produce an intelligent material for vibration damping. In the present study pure NiTiCu, NiTiCu/AlN and NiTiCu/AlN/NiTiCu heterostructures have been deposited on Si substrate using magnetron sputtering technique. By the use of the interfaces and shape memory effect provided by NiTiCu layers, the damping capacity can be increased along with increase in stiffness and mechanical hardness. The heterostructures were characterized in terms of structural, electrical, morphological and mechanical properties by X-ray diffraction (XRD), four probe resistivity method, atomic force microscopy, field emission scanning electron microscopy, and nanoindentation. The NiTiCu/AlN/NiTiCu heterostructure exhibit enhanced mechanical and damping properties as compared to NiTiCu/AlN and pure NiTiCu. This enhancement in hardness and damping of the heterostructure could be attributed to the shape memory effect of NiTiCu, intrinsic piezoelectricity of AlN and increased number of interfaces in heterostructure that help in dissipation of mechanical vibrations. The findings of this work provide additional impetus for the application of these heterostructures in emerging fields of nanotechnology and microelectro mechanical (MEMS) devices.

NiTiCu/AlN/NiTiCu shape memory thin film heterostructures for vibration damping in MEMS

International Nuclear Information System (INIS)

Kaur, Navjot; Kaur, Davinder

2014-01-01

Highlights: • Fabrication of NiTiCu/AlN/NiTiCu heterostructure using dc/rf magnetron sputtering. • Exhibits highest hardness (38 GPa) and elastic modulus (187 GPa). • Enhanced dissipation of mechanical energy (E d = 5.7 N J). • High damping capacity (0.052) and figure of merit (∼0.62). • Can be applied for vibration damping in MEMS. -- Abstract: Shape memory alloy (NiTiCu) thin films coupled with piezoelectric AlN layer produce an intelligent material for vibration damping. In the present study pure NiTiCu, NiTiCu/AlN and NiTiCu/AlN/NiTiCu heterostructures have been deposited on Si substrate using magnetron sputtering technique. By the use of the interfaces and shape memory effect provided by NiTiCu layers, the damping capacity can be increased along with increase in stiffness and mechanical hardness. The heterostructures were characterized in terms of structural, electrical, morphological and mechanical properties by X-ray diffraction (XRD), four probe resistivity method, atomic force microscopy, field emission scanning electron microscopy, and nanoindentation. The NiTiCu/AlN/NiTiCu heterostructure exhibit enhanced mechanical and damping properties as compared to NiTiCu/AlN and pure NiTiCu. This enhancement in hardness and damping of the heterostructure could be attributed to the shape memory effect of NiTiCu, intrinsic piezoelectricity of AlN and increased number of interfaces in heterostructure that help in dissipation of mechanical vibrations. The findings of this work provide additional impetus for the application of these heterostructures in emerging fields of nanotechnology and microelectro mechanical (MEMS) devices

Electronic structure of Pd42.5Ni7.5Cu30P20, an excellent bulk metallic glass former: Comparison to the Pd40Ni40P20 reference glass

International Nuclear Information System (INIS)

Hosokawa, S.; Sato, H.; Happo, N.; Mimura, K.; Tezuka, Y.; Ichitsubo, T.; Matsubara, E.; Nishiyama, N.

2007-01-01

In-house photoemission and inverse-photoemission spectra (PES and IPES) were measured on Pd 42.5 Ni 7.5 Cu 30 P 20 and Pd 40 Ni 40 P 20 bulk metallic glasses in order to clarify the origin of excellent glass-forming ability from the viewpoint of electronic structure. Minima are observed for both the metallic glasses at a slightly higher energy than the Fermi level. Incident photon-energy dependent PES spectra were obtained using synchrotron radiation and the Pd 4d partial density of states (DOS) was estimated from the PES data. Soft X-ray emission spectra were also measured near the Ni and Cu 2p 3/2 absorption edges to evaluate, respectively, the Ni and Cu 3d partial DOS in the valence band. The Pd 4d and the Ni and Cu 3d partials in the conduction band were obtained from X-ray absorption spectra around the Pd 3p 3/2 and Ni and Cu 2p 3/2 absorption edges, respectively. It was found that the Pd 4d partial DOS near the Fermi energy largely decreases and becomes localized by replacing the Ni atoms with the Cu atoms, which may be closely related to the excellent glass-forming ability of the Pd 42.5 Ni 7.5 Cu 30 P 20 bulk metallic glass due to a selective formation of Pd-P covalent bonds

Brazing of Cu with Pd-based metallic glass filler

Energy Technology Data Exchange (ETDEWEB)

Terajima, Takeshi [Joining and Welding Research Institute, Osaka University, 11-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan)], E-mail: terajima@jwri.osaka-u.ac.jp; Nakata, Kazuhiro [Joining and Welding Research Institute, Osaka University, 11-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Matsumoto, Yuji [Materials and Structures Laboratory, Tokyo Institute of Technology (Japan); Zhang, Wei; Kimura, Hisamichi; Inoue, Akihisa [Institute for Materials Research, Tohoku University (Japan)

2008-02-25

Metallic glass has several unique properties, including high mechanical strength, small solidification shrinkage, small elastic modulus and supercooling state, all of which are well suited as a residual stress buffer for metal and ceramic joining. In the present preliminary study, we demonstrated brazing of Cu rods with Pd{sub 40}Cu{sub 30}Ni{sub 10}P{sub 20} metallic glass filler. The brazing was carried out at 873 K for 1 min in a vacuum atmosphere (1 x 10{sup -3} Pa), and then the specimens were quenched at the rate of 30 K/s by blowing He. The metallic glass brazing of Cu using Pd{sub 40}Cu{sub 30}Ni{sub 10}P{sub 20} filler was successful, with the exception that several voids remained in the filler. According to micro-focused X-ray diffraction, no diffraction patterns were observed at both the center of the Pd{sub 40}Cu{sub 30}Ni{sub 10}P{sub 20} filler and the Cu/Pd{sub 40}Cu{sub 30}Ni{sub 10}P{sub 20} interface. The result showed that the Cu specimens were joined with Pd{sub 40}Cu{sub 30}Ni{sub 10}P{sub 20} filler in the glassy state. The tensile fracture strength of the brazed specimens ranged from 20 to 250 MPa. The crack extension from the voids in the Pd{sub 40}Cu{sub 30}Ni{sub 10}P{sub 20} filler may have caused the results to be uneven and very low compared to the strength of Pd-based bulk metallic glass.

Designing porous metallic glass compact enclosed with surface iron oxides

Energy Technology Data Exchange (ETDEWEB)

Cho, Jae Young; Park, Hae Jin; Hong, Sung Hwan; Kim, Jeong Tae; Kim, Young Seok; Park, Jun-Young; Lee, Naesung [Hybrid Materials Center (HMC), Faculty of Nanotechnology and Advanced Materials Engineering, Sejong University, 209 Neungdong-ro, Gwangjin-gu, Seoul 143-747 (Korea, Republic of); Seo, Yongho [Graphene Research Institute (GRI) & HMC, Faculty of Nanotechnology and Advanced Materials Engineering, Sejong University, 209 Neungdong-ro, Gwangjin-gu, Seoul 143-747 (Korea, Republic of); Park, Jin Man, E-mail: jinman_park@hotmail.com [Global Technology Center, Samsung Electronics Co., Ltd, 129 Samsung-ro, Yeongtong-gu, Suwon-si, Gyeonggi-do 443-742 (Korea, Republic of); Kim, Ki Buem, E-mail: kbkim@sejong.ac.kr [Hybrid Materials Center (HMC), Faculty of Nanotechnology and Advanced Materials Engineering, Sejong University, 209 Neungdong-ro, Gwangjin-gu, Seoul 143-747 (Korea, Republic of)

2015-06-25

Highlights: • Porous metallic glass compact was developed using electro-discharge sintering process. • Uniform PMGC can only be achieved when low electrical input energy was applied. • Functional iron-oxides were formed on the surface of PMGCs by hydrothermal technique. - Abstract: Porous metallic glass compact (PMGC) using electro-discharge sintering (EDS) process of gas atomized Zr{sub 41.2}Ti{sub 13.8}Cu{sub 12.5}Ni{sub 10}Be{sub 22.5} metallic glass powder was developed. The formation of uniform PMGC can only be achieved when low electrical input energy was applied. Functional iron-oxides were formed on the surface of PMGCs by hydrothermal technique. This finding suggests that PMGC can be applied in the new area such as catalyst via hydrothermal technique and offer a promising guideline for using the metallic glasses as a potential functional application.

Research on Zr50Al15-xNi10Cu25Yx amorphous alloys prepared by mechanical alloying with commercial pure element powders

International Nuclear Information System (INIS)

Long Woyun; Ouyang Xueqiong; Luo Zhiwei; Li Jing; Lu Anxian

2011-01-01

Amorphous Zr 50 Al 15-x Ni 10 Cu 25 Y x alloy powders were fabricated by mechanical alloying at low vacuum with commercial pure element powders. The effects on glass forming ability of Al partial substituted by Y in Zr 50 Al 15 Ni 10 Cu 25 and thermal stability of Si 3 N 4 powders addition were investigated. The as-milled powders were characterized by X-ray diffraction, scanning electron microscopy and differential scanning calorimeter. The results show that partial substitution of Al can improve the glass forming ability of Zr 50 Al 15 Ni 10 Cu 25 alloy. Minor Si 3 N 4 additions raise the crystallization activation energy of the amorphous phase and thus improve its thermal stability. -- Research Highlights: → ZrAlNiCu amorphous alloys can be synthesized by MA in low cost. → Appropriate amount of Al substituted by Y in ZrAlNiCu alloy can improve its glass forming ability. → A second phase particle addition helps to improve the thermal stability of the amorphous matrix.

Transient Liquid Phase Bonding of Cu-Cr-Zr-Ti Alloy Using Ni and Mn Coatings: Microstructural Evolution and Mechanical Properties

Science.gov (United States)

Venkateswaran, T.; Ravi, K. R.; Sivakumar, D.; Pant, Bhanu; Janaki Ram, G. D.

2017-08-01

High-strength copper alloys are used extensively in the regenerative cooling parts of aerospace structures. Transient liquid phase (TLP) bonding of a Cu-Cr-Zr-Ti alloy was attempted in the present study using thin layers of elemental Ni and Mn coatings applied by electroplating. One of the base metals was given a Ni coating of 4 µm followed by a Mn coating of 15 µm, while the other base metal was given only the Ni coating (4 µm). The bonding cycle consisted of the following: TLP stage—heating to 1030 °C and holding for 15 min; homogenization stage—furnace cooling to 880 °C and holding for 2 h followed by argon quenching to room temperature. Detailed microscopy and electron probe microanalysis analysis of the brazed joints were carried out. The braze metal was found to undergo isothermal solidification within the 15 min of holding time at 1030 °C. At the end of TLP stage, the braze metal showed a composition of Cu-17Ni-9Mn (wt.%) at the center of the joint with a steep gradient in Ni and Mn concentrations from the center of the braze metal to the base metal interfaces. After holding for 2 h at 880 °C (homogenization stage), the compositional gradients were found to flatten significantly and the braze metal was found to develop a homogeneous composition of Cu-11Ni-7Mn (wt.%) at the center of the joint. In lap-shear tests, failures were always found to occur in the base metal away from the brazed region. The copper alloy base metal was found to undergo significant grain coarsening due to high-temperature exposure during brazing and, consequently, suffer considerable reduction in yield strength.

Analysis of atomic mobility in a Cu38Zr46Ag8Al8 bulk metallic glass

International Nuclear Information System (INIS)

Qiao, J.C.; Pelletier, J.M.

2013-01-01

Highlights: ► Atomic mobility in Cu 38 Zr 46 Ag 8 Al 8 bulk metallic glass have been investigated by DMA. ► Loss factor is directly connected to the energy lost during application of the stress. ► Structural relaxation and crystallization induces a decrease of the atomic mobility. ► The concentration of quasi-point defects links to atomic mobility in metallic glasses. - Abstract: Atomic mobility in as-cast and annealed Cu 38 Zr 46 Ag 8 Al 8 bulk metallic glass samples is analyzed by performing dynamic mechanical analysis. The loss factor is directly connected to the energy lost during application of the stress. Structural relaxation process and crystallization lead to a decrease of the atomic mobility in the bulk metallic glass. A physical model, based on the concept of quasi point defects is introduced, to describe the atomic mobility. Movements in amorphous materials are correlated. The correlation factor χ reflects the atomic mobility in bulk metallic glasses: structural relaxation and crystallization lead to a decrease of χ, implying the reduction of atomic mobility. The evolution of elastic, visco-elastic and viscoplastic components after structural relaxation and partial crystallization state during the mechanical response has been obtained. Compared with as-cast state, structural relaxation induced an increase of elastic component and a decrease of visco-elastic component in the metallic glass.

The Effect of Ag Addition on the Enhancement of the Thermal and Mechanical Properties of CuZrAl Bulk Metallic Glasses

Directory of Open Access Journals (Sweden)

Tsan-Man Chung

2016-09-01

Full Text Available In this study, the thermal and mechanical properties of Cu50−xZr43Al7Agx (x = 0, 3, 4, 5, 6 bulk metallic glasses (BMGs are investigated by using an X-ray diffractometer (XRD, a differential scanning calorimeter (DSC, differential thermal analysis (DTA, a Vickers hardness tester, a material test system (MTS, scanning electron microscopy (SEM, and transmission electron microscopy (TEM. Cu50−xZr43Al7Agx (x = 0, 3, 4, 5, 6 BMGs were made by arc-melting and an injection casting process. The results revealed that the glass transition temperature (Tg and the crystallization temperature (Tx of CuZrAl alloy decreased with the Ag addition. Hence, the supercooled liquid region and γ of Cu45Zr43Al7Ag5 alloy increased to 76 K and 0.42, respectively. The thermal stability and glass forming ability of CuZrAlAg BMG alloys were enhanced by the microalloyed Ag content. The room temperature compressive fracture strength and strain measured of Cu47Zr43Al7Ag3 were about 2200 MPa and 2.1%, respectively. The distribution of vein patterns and the formation of nanocrystalline phases on the fracture surface of Cu47Zr43Al7Ag3 alloy can be observed by SEM and TEM to be significant, indicating a typical ductile fracture behavior and an improved plasticity of alloys with the addition of microalloyed Ag from 0 to 6 atom %.

Crystallization of Pd40CU30Ni10P20 bulk metallic glass with and without pressure

DEFF Research Database (Denmark)

Yang, B.; Jiang, Jianzhong; Zhuang, Yanxin

2007-01-01

The glass-transition behavior of Pd40Cu30Ni10P20 bulk metallic glass was investigated by differential scanning calorimetry (DSC) and X-ray powder diffraction (XRD). The effect of pressure on the crystallization behavior of Pd40Cu30Ni10P20 bulk glass was studied by in situ high-pressure and high...

Glass formation and crystallization in Zr based alloys

International Nuclear Information System (INIS)

Dey, G. K.

2011-01-01

Metallic glasses have come in to prominence in recent times because their nanocrystalline atomic arrangement imparts many useful and unusual properties to these metallic solids. Though these have been produced for the last four decades, the necessity of rapid solidification at cooling rates of 10 5 K/sec or higher for their production, have restricted their geometry to thin ribbons and prevented their application to many areas despite their excellent properties. It has been shown in recent investigations that, many Zr base multicomponent alloys can be obtained in glassy state by cooling at much lower rate typically 10 2 to 10 3 K/sec. This has enabled production of these alloys in the glassy stat in bulk. By now, bulk metallic glasses have been produced in Mg, Ln, Zr, Fe, Pd-Cu, Pd-Fe, Ti and Ni- based alloys. Production of these glasses in bulk has opened avenue for their application in many areas where their excellent mechanical properties an corrosion resistance can be exploited. The transformation of the amorphous phase in these alloys to one or more crystalline phases, is an interesting phase transformation and can lead to formation of crystals in a variety of morphologies and a wide range of crystal sizes, including nanometer size crystals or nanocrystals. The bulk amorphous alloys exhibit higher fracture stress, combined with higher hardness and lower young's modulus than those of any crystalline alloy. The Zr- and Ti-based bulk amorphous alloy exhibit high bending and flexural strength values which are typically 2.0 to 2.5 time higher than those for crystalline counterparts. The composites of bulk metallic glass containing crystalline phases have been found to have special properties. This has been demonstrated in the case of composites of bulk metallic glass and tungsten wires wit the glass forming the matrix. Such a composite has a very high impact strength and is especially suitable for application as an armour penetrator in various types of shells used

Length scale-dependent structural relaxation in Zr{sub 57.5}Ti{sub 7.5}Nb{sub 5}Cu{sub 12.5}Ni{sub 10}Al{sub 7.5} metallic glass

Energy Technology Data Exchange (ETDEWEB)

Scudino, S., E-mail: s.scudino@ifw-dresden.de [IFW Dresden, Institut für Komplexe Materialien, Helmholtzstraße 20, D-01069 Dresden (Germany); Stoica, M. [IFW Dresden, Institut für Komplexe Materialien, Helmholtzstraße 20, D-01069 Dresden (Germany); Kaban, I. [IFW Dresden, Institut für Komplexe Materialien, Helmholtzstraße 20, D-01069 Dresden (Germany); TU Dresden, Institut für Werkstoffwissenschaft, D-01062 Dresden (Germany); Prashanth, K.G. [IFW Dresden, Institut für Komplexe Materialien, Helmholtzstraße 20, D-01069 Dresden (Germany); Vaughan, G.B.M. [European Synchrotron Radiation Facilities ESRF, BP 220, 38043 Grenoble (France); Eckert, J. [IFW Dresden, Institut für Komplexe Materialien, Helmholtzstraße 20, D-01069 Dresden (Germany); TU Dresden, Institut für Werkstoffwissenschaft, D-01062 Dresden (Germany)

2015-08-05

Highlights: • Structural relaxation of metallic glasses studied by high-energy X-ray diffraction. • Free volume is not uniformly distributed across the atoms. • Annihilation of free volume (i.e. shrinking) during heating is observed in the MRO. • Increase of free volume (i.e. expansion) during heating occurs in the SRO. • First diffraction maximum in reciprocal space describes structural changes in MRO. - Abstract: Structural relaxation in ball-milled Zr{sub 57.5}Ti{sub 7.5}Nb{sub 5}Cu{sub 12.5}Ni{sub 10}Al{sub 7.5} glassy powders has been investigated by in-situ high-energy X-ray diffraction. The studies in reciprocal and real space reveal a contrasting behavior between medium- (MRO) and short-range order (SRO). The free volume is not uniformly distributed across the atoms: annihilation of free volume (i.e. shrinking) during heating is observed in the MRO, whereas an increase of free volume (i.e. expansion) occurs in the SRO, implying a denser SRO in the as-milled powder compared to the structurally relaxed material. This behavior is in agreement with the concepts of free volume and anti-free volume and can be attributed to the change of the coordination number in the first nearest-neighbor shell. Finally, the results demonstrate that the first diffuse diffraction maximum in reciprocal space is a reliable indicator to evaluate the structural changes occurring in the MRO.

Devitrification behavior and glass-forming ability of Cu-Zr-Ag alloys

International Nuclear Information System (INIS)

Louzguine-Luzgin, Dmitri V.; Xie, Guoqiang; Zhang, Wei; Inoue, Akihisa

2007-01-01

This paper presents an influence of Ag addition on the glass-forming ability and devitrification behavior of Cu-Zr glassy alloys on heating. The crystallization kinetics and structure changes in Cu 45 Zr 45 Ag 10 and Cu 35 Zr 45 Ag 20 glassy alloys on heating were studied by X-ray diffraction, transmission electron microscopy, differential scanning and isothermal calorimetry methods. Based on the results obtained one can assume that the improvement of the glass-forming ability of the Cu-Zr alloys by the addition of Ag is connected with a particular crystallization mechanism and a higher reduced glass-transition temperature of the Cu 45 Zr 45 Ag 10 ternary alloy compared to the binary Cu 55 Zr 45 counterpart. As observed in the present work crystallization of the Cu-Zr-Ag alloys is found to cause embitterment of the samples and should be avoided as these alloys are considered to be used as structural materials. The Cu 35 Zr 45 Ag 20 alloy shows possible submicron-scale phase separation upon annealing

Effects of B Addition on Glass Formation, Mechanical Properties and Corrosion Resistance of the Zr66.7- x Ni33.3B x ( x = 0, 1, 3, and 5 at.%) Metallic Glasses

Science.gov (United States)

Xu, Jing; Niu, Jiazheng; Zhang, Zitang; Ge, Wenjuan; Shang, Caiyun; Wang, Yan

2016-02-01

The effects of B addition on glass formation, mechanical properties and electrochemical corrosion of Zr66.7- x Ni33.3B x ( x = 0, 1, 3, and 5 at.%) glassy ribbons have been investigated. The results reveal that the B addition can improve the glass forming ability and obviously raise the thermal stability of the Zr-Ni-B metallic glasses. The 1 at.% B addition exhibits the most positive effect on enhancing the microhardness of Vickers-type (HV) by 13.83%. In addition, Zr63.7Ni33.3B3 possesses the best plasticity in the nanoindentation test. The electrochemical test and microstructural observation show that the moderate B addition effectively enhances the corrosion resistance of the Zr-Ni-B metallic glasses in different solutions. The 3 at.% B addition is beneficial to improve the corrosion resistance in the 0.5 M NaCl solution. But in the 1 M HCl and 2 M NaOH solutions, the better effect is induced by the 1 and 5 at.% B addition. Moreover, the Zr-Ni-B metallic glasses exhibit active dissolution behavior in the chloride- and hydrogen-containing solutions, but passivation occurs in the 2 M NaOH solution.

Anti-irradiation performance against helium bombardment in bulk metallic glass (Cu{sub 47}Zr{sub 45}Al{sub 8}){sub 98.5}Y{sub 1.5}

Energy Technology Data Exchange (ETDEWEB)

Mei, Xianxiu, E-mail: xxmei@dlut.edu.cn [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Dalian University of Technology, Ministry of Education, Dalian 116024 (China); Wang, Bin; Dong, Chuang; Gong, Faquan; Wang, Younian [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Dalian University of Technology, Ministry of Education, Dalian 116024 (China); Wang, Zhiguang [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

2013-07-15

Highlights: ► This paper used He{sup 2+} ion-irradiated metallic glass (Cu{sub 47}Zr{sub 45}Al{sub 8}){sub 98.5}Y{sub 1.5} and the W metal with the energy of 500 keV. ► There was no significant irradiation damage phenomenon on the surface of metallic glass at different irradiation fluences. ► For irradiated W, the peeling, delamination and flaking appeared numerously at fluences of 1 × 10{sup 18} and 2 × 10{sup 18} ions/cm{sup 2}. ► The resistance to He{sup 2+} irradiation of metallic glass (Cu{sub 47}Zr{sub 45}Al{sub 8}){sub 98.5}Y{sub 1.5} was superior to the one in W metal. -- Abstract: In order to compare the resistance to He{sup 2+} ion induced irradiation between metallic glass and polycrystal W metal, this paper used different fluences of He{sup 2+} ion-irradiated metallic glass (Cu{sub 47}Zr{sub 45}Al{sub 8}){sub 98.5}Y{sub 1.5} and polycrystal W with an energy of 500 keV. The SRIM simulation calculation results showed that the range (1.19 μm) of He{sup 2+} in metallic glass was greater than the one (0.76 μm) in polycrystal W. The SEM analysis showed that there was no significant irradiation damage phenomenon on the surface of metallic glass, and there was only a damage layer 1.45 μm away from the surface when the fluence reached 2 × 10{sup 18} ions/cm{sup 2}. For W, there were surface peeling, flaking and other surface damages at a fluence of 1 × 10{sup 18} ions/cm{sup 2}; when the fluence increased to 2 × 10{sup 18} ions/cm{sup 2}, multilayer detachment phenomenon appeared. The surface root mean square roughness of metallic glass (Cu{sub 47}Zr{sub 45}Al{sub 8}){sub 98.5}Y{sub 1.5} first increased and then decreased with the increase of fluence. The surface reflectivity of (Cu{sub 47}Zr{sub 45}Al{sub 8}){sub 98.5}Y{sub 1.5} decreased with the increase of fluence. Through detection by XRD, it was found that (Cu{sub 47}Zr{sub 45}Al{sub 8}){sub 98.5}Y{sub 1.5} always maintained amorphous phase after different fluences of radiation. The

Study of the glass forming ability of Cu60Zr32,5Ti7,5 alloy by molecular dynamics

International Nuclear Information System (INIS)

Schimidt, C.S.; Lima, L.V.; Bastos, I.N.; Aliaga, L.C.R.

2016-01-01

This article presents the results of molecular dynamics simulation of Cu 60 Zr 32.5 Ti 7.5 alloy through the open source code LAMMPS. Amorphous samples were produced by quenching the metallic molten from 2300K to 200K at cooling rates of 50, 5 and 0.5K/ps. The pair distribution functions of both the liquid and solid were calculated and compared at different temperatures. The topology of short-range order was analyzed using the Voronoi tessellation method, which determined the presence of Cu-centered icosahedral clusters as the prevailing in the amorphous state at 300K. Moreover, the sample was submitted to uniaxial tensile tests at strain rate of 10ps -1 , in order to investigate the mechanical behavior of the metallic glass. The result of the stress-strain curve showed that applied loads lead to the plastic regime. However, the presences of shear bands, typical in the experimental testing, were not observed. Moreover, the evolution of the viscosity above the glass transition temperature and the fragility of the alloy were determined. The solidus and liquidus temperatures were determined and a good agreement with experimental data was found. (author)

Preparation of Zr50Al15− xNi10Cu25Yx amorphous powders by ...

Indian Academy of Sciences (India)

The as-milled powders were characterized by X-ray diffraction and transmission electron microscopy. The results show that partial substitution of Al by Y can improve the glass-forming ability of Zr50Al15Ni10Cu25 alloy. Thermodynamic calculation of equivalent free energy shows that Zr50Al13.8Ni10Cu25Y1.2 alloy has the ...

Catalytic hydrotreatment of fast pyrolysis oil using bimetallic Ni-Cu catalysts on various supports

NARCIS (Netherlands)

Ardiyanti, A. R.; Khromova, S. A.; Venderbosch, R. H.; Yakovlev, V. A.; Melian-Cabrera, I. V.; Heeres, H. J.

2012-01-01

Bimetallic Ni-Cu catalysts on various Supports (CeO2-ZrO2, ZrO2, SiO2, TiO2, rice husk carbon, and Sibunite) with metal contents ranging from 7.5 to 9.0 (Ni) and 3.1-3.6 wt.% (Cu) for the inorganic supports and 17.1-17.8 (Ni) and 7.1-7.8 (Cu) for the carbon supports were synthesised and screened for

Effect of the Cu and Ni content on the crystallization temperature and crystallization mechanism of La–Al–Cu(Ni metallic glasses

Directory of Open Access Journals (Sweden)

Peiyou Li

2016-02-01

Full Text Available The effect of the Cu and Ni content on the crystallization mechanism and the crystallization temperatures of La–Al–Cu(Ni metallic glasses (MGs was studied by differential scanning calorimetry (DSC. The experimental results have shown that the DSC curves obtained for the La–Al–Cu and La–Al–Ni MGs exhibit two and three crystallization temperatures, respectively. The crystallization temperatures of the La–Al–Cu and La–Al–Ni MGs result from the merging and splitting of thermal events related to the corresponding eutectic atomic pairs in the La72Cu28 and La81.6Al18.4 MGs, and La72Ni28 and La81.6Al18.4 MGs, respectively. In addition, Al- and Ni-containing clusters with weak or strong atomic interaction in the Al–Ni atomic pairs strongly affect the crystallization mechanism and thus the crystallization temperature of La–Al–Ni MGs. This study provides a novel understanding of the relation between the crystallization temperature and the underlying crystallization mechanisms in La–Al–Cu(Ni MGs.

Two-phase quasi-equilibrium in β-type Ti-based bulk metallic glass composites

Science.gov (United States)

Zhang, L.; Pauly, S.; Tang, M. Q.; Eckert, J.; Zhang, H. F.

2016-01-01

The microstructural evolution of cast Ti/Zr-based bulk metallic glass composites (BMGCs) containing β-Ti still remains ambiguous. This is why to date the strategies and alloys suitable for producing such BMGCs with precisely controllable volume fractions and crystallite sizes are still rather limited. In this work, a Ti-based BMGC containing β-Ti was developed in the Ti-Zr-Cu-Co-Be system. The glassy matrix of this BMGC possesses an exceptional glass-forming ability and as a consequence, the volume fractions as well as the composition of the β-Ti dendrites remain constant over a wide range of cooling rates. This finding can be explained in terms of a two-phase quasi-equilibrium between the supercooled liquid and β-Ti, which the system attains on cooling. The two-phase quasi-equilibrium allows predicting the crystalline and glassy volume fractions by means of the lever rule and we succeeded in reproducing these values by slight variations in the alloy composition at a fixed cooling rate. The two-phase quasi-equilibrium could be of critical importance for understanding and designing the microstructures of BMGCs containing the β-phase. Its implications on the nucleation and growth of the crystalline phase are elaborated. PMID:26754315

Direct observation of radial distribution change during tensile deformation of metallic glass by high energy X-ray diffraction method

Energy Technology Data Exchange (ETDEWEB)

Nasu, Toshio, E-mail: nasu@kekexafs.kj.yamagata-u.ac.j [Faculty of Education, Arts and Science, Yamagata University, 1-4-12 Kojirakawa, Yamagata, Yamagata, 990-8560 (Japan); Sasaki, Motokatsu [Faculty of Education, Arts and Science, Yamagata University, 1-4-12 Kojirakawa, Yamagata, Yamagata, 990-8560 (Japan); Usuki, Takeshi; Sekine, Mai [Faculty of Science, Yamagata University, Yamagata 990-8560 (Japan); Takigawa, Yorinobu; Higashi, Kenji [Graduate School of Engineering, Osaka Prefecture University, Sakai 599-8531 (Japan); Kohara, Shinji [Japan Synchrotron Radiation Research Institute, Harima Science Garden City, Sayo town, Hyogo 679-5198 (Japan); Sakurai, Masaki; Wei Zhang; Inoue, Akihisa [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan)

2009-08-26

The purpose of this research is to investigate the micro-mechanism of deformation behavior of metallic glasses. We report the results of direct observations of short-range and medium-range structural change during tensile deformation of metallic glasses by high energy X-ray diffraction method. Cu{sub 50}Zr{sub 50} and Ni{sub 30}Zr{sub 70} metallic glass samples in the ribbon shape (1.5 mm width and 25 mum) were made by using rapid quenching method. Tensile deformation added to the sample was made by using special equipment adopted for measuring the high energy X-ray diffraction. The peaks in pair distribution function g(r) for Cu{sub 50}Zr{sub 50} and N{sub 30}iZr{sub 70} metallic glasses move zigzag into front and into rear during tensile deformation. These results of direct observation on atomic distribution change for Cu{sub 50}Zr{sub 50} and Ni{sub 30}Zr{sub 70} metallic glass ribbons during tensile deformation suggest that the micro-relaxations occur.

Zr61Ti2Cu25Al12 metallic glass for potential use in dental implants: biocompatibility assessment by in vitro cellular responses.

Science.gov (United States)

Li, Jing; Shi, Ling-ling; Zhu, Zhen-dong; He, Qiang; Ai, Hong-jun; Xu, Jian

2013-05-01

In comparison with titanium and its alloys, Zr61Ti2Cu25Al12 (ZT1) bulk metallic glass (BMG) manifests a good combination of high strength, high fracture toughness and lower Young's modulus. To examine its biocompatibility required for potential use in dental implants, this BMG was used as a cell growth subtract for three types of cell lines, L929 fibroblasts, human umbilical vein endothelial cells (HUVEC), and osteoblast-like MG63 cells. For a comparison, these cell lines were in parallel cultured and grown also on commercially pure titanium (CP-Ti) and Ti6-Al4-V alloy (Ti64). Cellular responses on the three metals, including adhesion, morphology and viability, were characterized using the SEM visualization and CCK-8 assay. Furthermore, real-time RT-PCR was used to measure the activity of integrin β, alkaline phosphatase (ALP) and type I collagen (COL I) in adherent MG63 cells. As indicated, in all cases of three cell lines, no significant differences in the initial attachment and viability/proliferation were found between ZT1, CP-Ti, and Ti64 until 5d of incubation period. It means that the biocompatibility in cellular response for ZT1 BMG is comparable to Ti and its alloys. For gene expression of integrin β, ALP and COL I, mRNA level from osteoblast cells grown on ZT1 substrates is significantly higher than that on the CP-Ti and Ti64. It suggests that the adhesion and differentiation of osteoblasts grown on ZT1 are even superior to those on the CP-Ti and Ti64 alloy, then promoting bone formation. The good biocompatibility of ZT1 BMG is associated with the formation of zirconium oxide layer on the surface and good corrosion-resistance in physiological environment. Copyright © 2013 Elsevier B.V. All rights reserved.

Combination of a Nd:YAG laser and a liquid cooling device to (Zr53Cu30Ni9Al8)Si0.5 bulk metallic glass welding

International Nuclear Information System (INIS)

Wang, H.S.; Chen, H.G.; Jang, J.S.C.; Chiou, M.S.

2010-01-01

Research highlights: → A liquid cooling device (LCD) helps to produce a lower initial welding temperature. → A lower initial welding temperature leads to a faster welding thermal cycle (WTC). → A faster WTC produces a crystallization free weld for a laser welded Zr-based BMG. - Abstract: Using pre-selected welding parameters, a crystallization-free weld for (Zr 53 Cu 30 Ni 9 Al 8 )Si 0.5 bulk metallic glass (BMG) was successfully produced by adopting a Nd:YAG pulse laser in combination with a liquid cooling device (LCD). When a LCD was employed, a faster cooling rate and shorter retention time for the crystallization temperature interval were produced, thus, no crystallization was observed in the weld fusion zone (WFZ) or heat affected zone (HAZ). The hardness in those areas did not differ significantly in comparison to the parent material (PM). For the room temperature laser weld (LCD was not employed), HAZ crystallization seemed unavoidable, although no crystallization occurred within the WFZ. The major crystalline phase in the HAZ was identified as Zr 2 Cu. When the precipitates were greater in the crystallized area (i.e., HAZ), cracks were more likely to form, thus, hardness in the area was decreased.

Containerless Measurement of Thermophysical Properties of Ti-Zr-Ni Alloys

Science.gov (United States)

Hyers, Robert; Bradshaw, Richard C.; Rogers, Jan C.; Rathz, Thomas J.; Lee, Geun W.; Gangopadhyay, Anup K.; Kelton, Kenneth F.

2004-01-01

The surface tension, viscosity, density, and thermal expansion of Ti-Zr-Ni alloys were measured for a number of compositions by electrostatic levitation methods. Containerless methods greatly reduce heterogeneous nucleation, increasing access to the undercooled liquid regime at finite cooling rates. The density and thermal expansion are measured optically, while the surface tension and viscosity are measured by the oscillating drop method. The measured alloys include compositions which form a metastable quasicrystal phase from the undercooled liquid, and alloys close to the composition of several multi-component bulk metallic glass-forming alloys. Measurements of surface tension show behavior typical of transition metals at high temperature, but a sudden decrease in the deeply undercooled liquid for alloys near the quasicrystal-forming composition range, but not for compositions which form the solid-solution phase first.

Welding of CuZr-based metallic glasses on air; Soldagem ao ar de ligas vitreas baseadas em Cu e Zr

Energy Technology Data Exchange (ETDEWEB)

Batalha, W.; Gargarella, P.; Kiminami, C.S., E-mail: wbatalha@dema.ufscar.br [Universidade Federal de Sao Carlos (UFSCar), SP (Brazil). Departamento de Engenharia de Materiais

2016-07-01

Metallic glass alloys have been studied aiming at its exceptional mechanical properties. This alloys processing's requires high cooling rates, which diminishes the sample's size. There by welding these samples without the loss of amorphous structure is a good alternative. The DEMa group has developed a technique based on Joule effect heating. By applying pressure and electric current, reaching temperatures of super cold liquids (the temperature between crystallizing and vitric transition), the vitric metal has it’s viscosity reduced and sample binding occur. The objective of this paper was to weld samples of cylindrical geometry of 2 and 3 mm in diameter and 4 mm in length of the compositions Cu46Zr42Al7Y5 and (Cu47Zr45Al8)98Y2. The process was done using 2 copper electrodes under(over) argon flux. The samples were later analysed by microscopy, differential scanning calorimetry and X ray diffraction. The results showed that this kind of welding process is possible since crystal formation on the welding region did not occur and there were no faults like cracks or porosity. (author)

Modification of the Ti40Cu36Zr10Pd14 BMG Crystallization Mechanism with Heating Rates 10-140 K/min

Science.gov (United States)

Czeppe, T.; Sypien, A.; Wierzbicka-Miernik, A.

2016-12-01

The article presents investigations of Ti40Cu36Zr10Pd14 bulk metallic glass crystallization process heated with the rates of 10, 60, 100 and 140 K/min. High heating rates experiments were performed in a new type of differential scanning calorimeter equipped with a fast responding thermal sensor. Phase composition and microstructure were studied with x-ray diffraction and transmission electron microscopy. The observed crystallization proceeded in two separate steps. Applied high rates of heating/cooling resulted in the crystallization of only one CuTi phase, replacing typical multi-phase crystallization. The microstructure after crystallization was polycrystalline with some amount of amorphous phase retained. Kinetic parameters were determined with the use of the Kissinger and Friedman iso-conversional analysis and Matusita-Sakka iso-kinetic model. The kinetic analysis supplies results concerning autocatalytically activated mechanism of primary crystallization with decreasing activation energy and small density of quenched-in nuclei, in good agreement with previous structural investigations. The mechanism of secondary crystallization required dense nuclei site, increasing activation energy and large nucleation frequency. The amorphous phase of Ti40Cu36Zr10Pd14 BMG revealed high thermal stability against crystallization. Application of high heating rates in DSC experiments might be useful for the determination of mechanism and kinetic parameters in investigations of metallic glasses crystallization, giving reasonable results.

Characterization of a glass frit free TiCuAg-thick film metallization applied on aluminium nitride

International Nuclear Information System (INIS)

Reicher, R.; Smetana, W.; Adlassnig, A.; Schuster, J. C.; Gruber, U.

1997-01-01

The metallization of aluminium nitride substrates by glass frit free Ti CuAg-thick film pastes were investigated. Adhesion properties of the conductor paste were tested by measuring tensile strength and compared with commercial Cu-thick film pastes (within glass frit). Also numerical analysis of temperature-distribution and thermal extension of metallized aluminium nitride ceramic, induced by a continuous and a pulsed working electronic device were made with a finite element program. (author)

Liquid -to-glass transition in bulk glass-forming Cu55-xZr45Agx alloys using molecular dynamic simulations

Directory of Open Access Journals (Sweden)

Celtek M.

2011-05-01

Full Text Available We report results from molecular dynamics (MD studies concerning the microscopic structure of the ternary, bulk metallic glass-forming Cu55-x Zr45Agx (x=0,10,20 alloys using tight-binding potentials. Understanding of the nature of Glass Forming Ability (GFA of studied alloys, GFA parameters, glass transition temperature (T-g, melting temperature (T-m, reduced glass transition temperature (T-g/T-m, the supercooled liquid region and other parameters were simulated and compared with experiments. The computed pair distribution functions reproduce well experimental x-ray data of Inoue and co-workers. Structure analysis of the Cu-Zr-Ag alloy based on MD simulation will be also presented

Characteristics of slowly cooled Zr-Al-Cu-Ni bulk samples with different oxygen content

International Nuclear Information System (INIS)

Gebert, A.; Eckert, J.; Bauer, H.-D.; Schultz, L.

1998-01-01

Bulk samples of the glass-forming Zr 65 Al 7.5 Cu 17.5 Ni 10 and Zr 55 Al 10 Cu 30 Ni 5 alloys with 3 mm diameter were prepared by die casting into a copper mould. The oxygen content of the samples was varied between 0.26 at.% and 0.73 at.% by adjusting the oxygen partial pressure in the argon atmosphere upon casting. Characterization of the microstructure of as-cast samples and of specimens continuously heated to 873 K was carried out by X-ray diffraction (XRD), optical microscopy (OM) and transmission electron microscopy (TEM). Thermal stability was investigated by constant-rate differential scanning calorimetry (DSC). The phase formation and the thermal stability of the slowly cooled zirconium-based bulk samples are essentially influenced by the oxygen content of the material. Furthermore, the sensitivity to oxygen depends on the composition of the alloy. In bulk Zr 65 Al 7.5 Cu 17.5 Ni 10 samples only small oxygen traces induce nucleation and crystal growth during slow cooling whereas Zr 55 Al 10 Cu 30 Ni 5 samples are completely amorphous for all oxygen contents investigated. The processes of the oxygen-induced phase formation are discussed in detail also with respect to the results obtained for the heat treated samples. With increasing oxygen content the thermal stability deteriorates, as it is obvious from a diminution of the supercooled liquid region (ΔT x = T x - T g ) which is mainly due to a reduction of the crystallization temperature T x . Furthermore, the thermal behaviour of Zr 65 Al 7.5 Cu 17.5 Ni 10 and Zr 55 Al 10 Cu 30 Ni 5 reveals significant differences. (orig.)

Insights on the Role of Copper Addition in the Corrosion and Mechanical Properties of Binary Zr-Cu Metallic Glass Coatings

Directory of Open Access Journals (Sweden)

Junlei Tang

2017-12-01

Full Text Available The effect of copper addition on the corrosion resistance and mechanical properties of binary Zr100–xCux (x = 30, 50, 80, 90 at.% glassy coatings was investigated by means of electrochemical measurements, scanning electron microscopy (SEM, energy dispersive analysis spectroscopy (EDS, X-ray photoelectron spectroscopy (XPS and nano-indentation techniques. The corrosion resistance in 0.01 M deaerated H2SO4 solution and the mechanical properties of the Zr-Cu glassy coatings depend considerably upon the copper content in the glassy matrix. The top surfaces of the Zr-Cu coatings with lower Cu content were covered by a compact protective ZrO2 passive film. The competition between the oxidation of Zr atoms (ZrO2 film formation and the oxidation–dissolution of Cu atoms assumed the most important role in the electrochemical behavior of the Zr-Cu glassy coatings. The generation of ZrO2 on the surface benefited the formation of passive film; and the corrosion resistance of the metallic glass coatings depended on the coverage degree of ZrO2 passive film. The evolution of free volume affected both the mechanical and corrosion behaviors of the Zr-Cu glassy coatings.

Preparation and characterization of Zr-based bulk metallic glasses in form of plate

International Nuclear Information System (INIS)

Pilarczyk, Wirginia

2014-01-01

Highlights: • Zr-based BMGs in form of plate was successful produced by die pressure casting method. • Many techniques have been used to characterize the structure of Zr 55 Cu 30 Ni 5 Al 10 alloy. • The calculated GFA parameters show that the alloy exhibits satisfactory GFA. • The studies reveal that tested as-cast Zr-based alloy is in amorphous state. - Abstract: Zr-based bulk metallic glasses present an interesting combination of physical, chemical and mechanical properties. During the last decade, intensive progress has been made and a number of applications have been suggested for these materials. In order to successfully apply these materials, it is necessary to accurately characterize their structure, thermal stability and other properties accurately. The aim of the presented work is the manufacturing, examination of the structure of selected Zr-based bulk metallic alloys and confirmation of an amorphous structure using X-ray analysis, microscopic observation and thermal analysis. In this work, the Zr-based bulk metallic glasses in form of plate was successful produced by die pressure casting method. Designed scientific station for casting zirconium based amorphous alloys in the form of plates and rods with selected dimensions is in our university a comprehensive method for achieving amorphous materials which enables us to maintain repeatability of as-cast samples with the amorphous structure and the assumed dimensions range. The diffraction pattern and exothermic reaction as well as the fracture surface morphology reveal that studied as-cast Zr-based alloy is in amorphous state. The calculated GFA parameters show that the alloy exhibits satisfactory glass-forming ability in form of studied plate. These obtained values can suggest that studied alloys are suitable materials for further planned practical application at welding process. The success of Zr-based bulk metallic glasses production in form of plate with obtained sizes is important for future

Preparation and characterization of Zr-based bulk metallic glasses in form of plate

Energy Technology Data Exchange (ETDEWEB)

Pilarczyk, Wirginia, E-mail: wirginia.pilarczyk@polsl.pl

2014-12-05

Highlights: • Zr-based BMGs in form of plate was successful produced by die pressure casting method. • Many techniques have been used to characterize the structure of Zr{sub 55}Cu{sub 30}Ni{sub 5}Al{sub 10} alloy. • The calculated GFA parameters show that the alloy exhibits satisfactory GFA. • The studies reveal that tested as-cast Zr-based alloy is in amorphous state. - Abstract: Zr-based bulk metallic glasses present an interesting combination of physical, chemical and mechanical properties. During the last decade, intensive progress has been made and a number of applications have been suggested for these materials. In order to successfully apply these materials, it is necessary to accurately characterize their structure, thermal stability and other properties accurately. The aim of the presented work is the manufacturing, examination of the structure of selected Zr-based bulk metallic alloys and confirmation of an amorphous structure using X-ray analysis, microscopic observation and thermal analysis. In this work, the Zr-based bulk metallic glasses in form of plate was successful produced by die pressure casting method. Designed scientific station for casting zirconium based amorphous alloys in the form of plates and rods with selected dimensions is in our university a comprehensive method for achieving amorphous materials which enables us to maintain repeatability of as-cast samples with the amorphous structure and the assumed dimensions range. The diffraction pattern and exothermic reaction as well as the fracture surface morphology reveal that studied as-cast Zr-based alloy is in amorphous state. The calculated GFA parameters show that the alloy exhibits satisfactory glass-forming ability in form of studied plate. These obtained values can suggest that studied alloys are suitable materials for further planned practical application at welding process. The success of Zr-based bulk metallic glasses production in form of plate with obtained sizes is

Structure, phase composition and microhardness of vacuum-arc multilayered Ti/Al, Ti/Cu, Ti/Fe, Ti/Zr nano-structures with different periods

Energy Technology Data Exchange (ETDEWEB)

Demchishin, A.V., E-mail: ademch@meta.ua [Institute of Problems in Material Science, NASU, Kiev (Ukraine); Gnilitskyi, I., E-mail: iaroslav.gnilitskyi@unimore.it [DISMI – Department of Sciences and Methods for Engineering, University of Modena and Reggio Emilia, Reggio Emilia (Italy); Orazi, L., E-mail: leonardo.orazi@unimore.it [DISMI – Department of Sciences and Methods for Engineering, University of Modena and Reggio Emilia, Reggio Emilia (Italy); Ascari, A., E-mail: a.ascari@unibo.it [DIN – Department of Industrial Engineering, University of Bologna, Bologna (Italy)

2015-07-01

Highlights: • Multilayer coatings of Ti/Fe, Ti/Al, Ti/Cu and Ti/Zr are generated. • Microstructure and morphology of the different systems are investigated. • XR diffraction analysis was performed to investigate phases composition. • Effects of inter metallic phases on microhardess are investigated. • Correlations between parameters and layer thickness are outlined. - Abstract: The microstructure, phase composition and microhardness of multilayered Ti/Al, Ti/Cu, Ti/Fe and Ti/Zr condensates produced on stainless steel substrates via vacuum-arc evaporation of pure metals were studied. The sublayer periods (Λ) were regulated in the range 80–850 nm by varying the vacuum discharge current and the duration of the successive depositions of metallic plasma onto the substrates while maintaining the total deposition time constant. The regularity of the obtained nanostructures was investigated by scanning and transmission electron microscopy while phase compositions were identified with X-ray diffraction (XRD) analysis in order to evidence the presence of interdiffusion and the amount of intermetallics. Condensates cross sections were mechanically characterized by means of microhardness tests. Measurements were correlated to the periods and to the presence of intermetallics.

Structure, phase composition and microhardness of vacuum-arc multilayered Ti/Al, Ti/Cu, Ti/Fe, Ti/Zr nano-structures with different periods

International Nuclear Information System (INIS)

Demchishin, A.V.; Gnilitskyi, I.; Orazi, L.; Ascari, A.

2015-01-01

Highlights: • Multilayer coatings of Ti/Fe, Ti/Al, Ti/Cu and Ti/Zr are generated. • Microstructure and morphology of the different systems are investigated. • XR diffraction analysis was performed to investigate phases composition. • Effects of inter metallic phases on microhardess are investigated. • Correlations between parameters and layer thickness are outlined. - Abstract: The microstructure, phase composition and microhardness of multilayered Ti/Al, Ti/Cu, Ti/Fe and Ti/Zr condensates produced on stainless steel substrates via vacuum-arc evaporation of pure metals were studied. The sublayer periods (Λ) were regulated in the range 80–850 nm by varying the vacuum discharge current and the duration of the successive depositions of metallic plasma onto the substrates while maintaining the total deposition time constant. The regularity of the obtained nanostructures was investigated by scanning and transmission electron microscopy while phase compositions were identified with X-ray diffraction (XRD) analysis in order to evidence the presence of interdiffusion and the amount of intermetallics. Condensates cross sections were mechanically characterized by means of microhardness tests. Measurements were correlated to the periods and to the presence of intermetallics

Characteristic of improved fatigue performance for Zr-based bulk metallic glass matrix composites

International Nuclear Information System (INIS)

Qiao, J.W.; Huang, E.W.; Wang, G.Y.; Yang, H.J.; Liang, W.; Zhang, Y.; Liaw, P.K.

2013-01-01

Zr 58.5 Ti 14.3 Nb 5.2 Cu 6.1 Ni 4.9 Be 11.0 bulk metallic glass matrix composites exhibit improved four-point-bending fatigue endurance with a fatigue limit of 567 MPa, compared to that under the tension–tension fatigue, due to the high-volume-fractioned dendrites, which can effectively blunt the fatigue-induced cracks. Illuminated by high-energy synchrotron X-ray at 200 and 100 K, the corresponding diffraction peaks, such as (110), (200), and (211) shift rightward to small lattice spacings, compared to those at 298 K. However, the peak widths at 100 K and 200 K are almost identical to that of room temperature. Since an identical fatigue specimen was measured under room temperature, 200 K, and 100 K, the invariant of the peak widths reveal the fact of the irreversible microstructure developments induced by fatigue. Even if the fatigue fracture stress is distinguishingly lower than the yielding strength, the deformation of dendrites locally prevails, evidenced by the occurrence of dislocations

Phase transformations in Zr-29.56 at.% Cu-19.85 at.% Ni melt-spun high-temperature shape memory alloy

International Nuclear Information System (INIS)

Firstov, G.S.; Koval, Yu.N.; Van Humbeeck, J.; Portier, R.; Vermaut, P.; Ochin, P.

2006-01-01

The present paper focuses on the phase transformations during crystallization of the melt-spun Zr-29.56 at.% Cu-19.85 at.% Ni high-temperature shape memory alloy (HTSMA). This alloy exhibits a martensitic transformation in the bulk polycrystalline state at temperatures above crystallization of the metallic glass with the same composition. The crystallization kinetics were investigated by differential scanning calorimetry. The intermediate and final products of crystallization for this HTSMA were studied by means of transmission electron microscopy. The chain of the transformations starting from crystallization and ending at martensitic transformation will be described. Perspectives of the thin film production of Zr-based HTSMA will be discussed

Phase transformations in Zr-29.56 at.% Cu-19.85 at.% Ni melt-spun high-temperature shape memory alloy

Energy Technology Data Exchange (ETDEWEB)

Firstov, G.S. [Institute for Metal Physics, National Academy of Sciences, 36 Vernadsky blvd., UA-03680, Kiev-142 (Ukraine)]. E-mail: gfirst@imp.kiev.ua; Koval, Yu.N. [Institute for Metal Physics, National Academy of Sciences, 36 Vernadsky blvd., UA-03680, Kiev-142 (Ukraine); Van Humbeeck, J. [Department MTM, Catholic University of Leuven, Kasteelpark Arenberg 44, B-3001 Heverlee (Leuven) (Belgium); Portier, R. [Laboratoire de Metallurgie Structurale ENSCP, 11 rue Pierre et Marie Curie, 75231 Paris Cedex 05 (France); Vermaut, P. [Laboratoire de Metallurgie Structurale ENSCP, 11 rue Pierre et Marie Curie, 75231 Paris Cedex 05 (France); Ochin, P. [Centre d' Etudes de Chimie Metallurgique-CNRS UPR2801, 15 rue Georges Urbain, 94407 Vitry-sur-Seine (France)

2006-11-25

The present paper focuses on the phase transformations during crystallization of the melt-spun Zr-29.56 at.% Cu-19.85 at.% Ni high-temperature shape memory alloy (HTSMA). This alloy exhibits a martensitic transformation in the bulk polycrystalline state at temperatures above crystallization of the metallic glass with the same composition. The crystallization kinetics were investigated by differential scanning calorimetry. The intermediate and final products of crystallization for this HTSMA were studied by means of transmission electron microscopy. The chain of the transformations starting from crystallization and ending at martensitic transformation will be described. Perspectives of the thin film production of Zr-based HTSMA will be discussed.

High-temperature deformation of dispersion-strengthened Cu-Zr-Ti-C alloys

International Nuclear Information System (INIS)

Palma, Rodrigo H.; Sepulveda, Aquiles; Espinoza, Rodrigo; Dianez, M. Jesus; Criado, Jose M.; Sayagues, M. Jesus

2005-01-01

The hot mechanical behaviour and microstructure of Cu-5 vol.% TiC, Cu-5 vol.% ZrO 2 and Cu-2.5 vol.% TiC-2.5 vol.% ZrO 2 alloys prepared by reaction milling were studied. After a test of 1 h annealing at 1173 K, the Cu-5 vol.% ZrO 2 alloy presented the lower softening resistance to annealing, while the other two ones kept their initial room-temperature hardness (about 2 GPa). Hot-compression tests at 773 and 1123 K, at initial true strain rates of 0.85 x 10 -3 and 0.85 x 10 -4 s -1 were performed. The Cu-2.5 vol.% TiC-2.5 vol.% ZrO 2 and the Cu-5 vol.% ZrO 2 alloys were the strongest and softest materials, respectively. Moreover, by electron microscopy, nanometric TiC and micrometric particles were detected in the Cu-5 vol.% TiC and Cu-5 vol.% ZrO 2 alloys, respectively. A possible explanation for the observed behaviour of these materials is proposed. In the compression tests, it was also found that strain rate has a low effect on flow stress, as it has been previously observed by various authors in dispersion-strengthened alloys deformed at high temperatures

Investigation of crystallization kinetics and deformation behavior in supercooled liquid region of CuZr-based bulk metallic glass

Energy Technology Data Exchange (ETDEWEB)

Yang, Ke; Fan, Xinhui; Li, Bing; Li, Yanhong; Wang, Xin; Xu, Xuanxuan [Xi' an Technological Univ. (China). School of Material and Chemical Engineering

2017-08-15

In this paper, a systematic study of crystallization kinetics and deformation behavior is presented for (Cu{sub 50}Zr{sub 50}){sub 94}Al{sub 6} bulk metallic glass in the supercooled liquid region. Crystallization results showed that the activation energy for (Cu{sub 50}Zr{sub 50}){sub 94}Al{sub 6} was calculated using the Arrhenius equation in isothermal mode and the Kissinger-Akahira-Sunose method in non-isothermal mode. The activation energy was quite high compared with other bulk metallic glasses. Based on isothermal transformation kinetics described by the Johson-Mehl-Avrami model, the average Avrami exponent of about 3.05 implies a mainly diffusion controlled three-dimensional growth with an increasing nucleation rate during the crystallization. For warm deformation, the results showed that deformation behavior, composed of homogeneous and inhomogeneous deformation, is strongly dependent on strain rate and temperature. The homogeneous deformation transformed from non-Newtonian flow to Newtonian flow with a decrease in strain rate and an increase in temperature. It was found that the crystallization during high temperature deformation is induced by heating. The appropriate working temperature/strain rate combination for the alloy forming, without in-situ crystallization, was deduced by constructing an empirical deformation map. The optimum process condition for (Cu{sub 50}Zr{sub 50}){sub 94}Al{sub 6} can be expressed as T∝733 K and ∝ ε 10{sup -3} s{sup -1}.

Microstructural evolution of Ni57Nb33Zr5Co5 metallic glass

Energy Technology Data Exchange (ETDEWEB)

Dulnee, S.; Gargarella, P.; Kiminami, C.S. [Universidade Federal de Sao Carlos (UFSCar), SP (Brazil); Kaufman, M. [Colorado School of Mines, (United States)

2016-07-01

Full text: The Ni57Nb33Zr5Co5 metallic glass is a promising alloy to be used as bipolar plates in proton exchange membrane (PEM) fuel cells. It is important to know which phase forms in this alloy under different cooling rates in order to investigate its influence in the thermal stability and mechanical properties of this alloy. In this work, different rapid solidified samples were prepared and their phase formation and microstructure were investigated by X ray diffraction (XRD), differential scanning calorimetry (DSC), optical microscopy, and scanning electron microscopy (SEM). It is found that in the samples with the highest cooling rate (ribbons) a fully glassy structure is attained. For the lower cooling rate samples (ingot, 2mm and 3 mm diameter rods), an complete crystalline structure forms with the presence of the equilibrium phases of Ni3(Nb,Zr) and Nb7Ni6 as primary phase or in an eutectic structure. As for the samples with an intermediate cooling rate (1 mm diameter rods) a polymorphic solidification occurs. Crystals of a metastable phase with spherical morphology precipitate in a glassy matrix with virtually the same composition and the spherical morphology is connected with the absence of constitutional undercooling during solidification. (author)

Is Cu60Ti10Zr30 a bulk glass-forming alloy?

DEFF Research Database (Denmark)

Jiang, Jianzhong; Saida, J.; Kato, H.

2003-01-01

. Nanocrystals with a significant volume fraction are randomly distributed in the amorphous matrix. The copper element is enriched in nanocrystals while a slightly high zirconium content is found in the matrix. We classify that the Cu60Ti10Zr30 alloy prepared by both of the aforementioned methods...

H-Phase Precipitation and Martensitic Transformation in Ni-rich Ni-Ti-Hf and Ni-Ti-Zr High-Temperature Shape Memory Alloys

Science.gov (United States)

Evirgen, A.; Pons, J.; Karaman, I.; Santamarta, R.; Noebe, R. D.

2018-03-01

The distributions of H-phase precipitates in Ni50.3Ti29.7Hf20 and Ni50.3Ti29.7Zr20 alloys formed by aging treatments at 500 and 550 °C or slow furnace cooling and their effects on the thermal martensitic transformation have been investigated by TEM and calorimetry. The comparative study clearly reveals faster precipitate-coarsening kinetics in the NiTiZr alloy than in NiTiHf. For precipitates of a similar size of 10-20 nm in both alloys, the martensite plates in Ni50.3Ti29.7Zr20 have larger widths and span a higher number of precipitates compared with the Ni50.3Ti29.7Hf20 alloy. However, for large H-phase particles with hundreds of nm in length, no significant differences in the martensitic microstructures of both alloy systems have been observed. The martensitic transformation temperatures of Ni50.3Ti29.7Hf20 are 80-90 °C higher than those of Ni50.3Ti29.7Zr20 in the precipitate-free state and in the presence of large particles of hundreds on nm in length, but this difference is reduced to only 10-20 °C in samples with small H-phase precipitates. The changes in the transformation temperatures are consistent with the differences in the precipitate distributions between the two alloy systems observed by TEM.

Moessbauer and transport studies of amorphous and icosahedral Zr-Ni-Cu-Ag-Al alloys

International Nuclear Information System (INIS)

Stadnik, Z.M.; Rapp, O.; Srinivas, V.; Saida, J.; Inoue, A.

2002-01-01

The alloy Zr 65 Al 7.5 Ni 10 Cu 7.3 Fe 0.2 Ag 10 in the amorphous and icosahedral states, and the bulk amorphous alloy Zr 65 Al 7.5 Ni 10 Cu 7.5 Ag 10 , have been studied with 57 Fe Moessbauer spectroscopy, electrical resistance and magnetoresistance techniques. The average quadrupole splitting in both alloys decreases with temperature as T 3/2 . The average quadrupole splitting in the icosahedral alloy is the largest ever reported for a metallic system. The lattice vibrations of the Fe atoms in the amorphous and icosahedral alloys are well described by a simple Debye model, with the characteristic Moessbauer temperatures of 379(29) and 439(28) K, respectively. Amorphous alloys Zr 65 Al 7. )5Ni 10 Cu 7.5 Ag 10 and Zr 65 Al 7.5 Ni 10 Cu 7.3 Fe 0.2 Ag 10 have been found to be superconducting with the transition temperature, T c , of about 1.7 K. The magnitude of Tc and the critical field slope at Tc are in agreement with previous work on Zr-based amorphous superconductors, while the low-temperature normal state resistivity is larger than typical results for binary and ternary Zr-based alloys. The resistivity of icosahedral Zr 65 Al 7.5 Ni 10 Cu 7.3 Fe 0.2 Ag 10 is larger than that for the amorphous ribbon of the same composition, as inferred both from direct measurements on the ribbons and from the observed magnetoresistance. However the icosahedral sample is non-superconducting in the measurement range down to 1.5 K. The results for the resistivity and the superconducting T c both suggest a stronger electronic disorder in the icosahedral phase than in the amorphous phase. (author)

Fabricating Zr-Based Bulk Metallic Glass Microcomponent by Suction Casting Using Silicon Micromold

Directory of Open Access Journals (Sweden)

Zhijing Zhu

2014-08-01

Full Text Available A suction casting process for fabricating Zr55Cu30Al10Ni5 bulk metallic glass microcomponent using silicon micromold has been studied. A complicated BMG microgear with 50 μm in module has been cast successfully. Observed by scanning electron microscopy and laser scanning confocal microscopy, we find that the cast microgear duplicates the silicon micromold including the microstructure on the surface. The amorphous state of the microgear is confirmed by transmission election microscopy. The nanoindentation hardness and elasticity modulus of the microgear reach 6.5 GPa and 94.5 GPa. The simulation and experimental results prove that the suction casting process with the silicon micromold is a promising one-step method to fabricate bulk metallic glass microcomponents with high performance for applications in microelectromechanical system.

Study of the glass forming ability of Cu{sub 60}Zr{sub 32,5}Ti{sub 7,5} alloy by molecular dynamics; Formacao de fase amorfa na liga Cu{sub 60}Zr{sub 32,5}Ti{sub 7,5} por dinamica molecular

Energy Technology Data Exchange (ETDEWEB)

Schimidt, C.S.; Lima, L.V.; Bastos, I.N.; Aliaga, L.C.R., E-mail: camilaschimidt17@gmail.com [Universidade do Estado do Rio de Janeiro (UERJ), Nova Friburgo, RJ (Brazil). Departamento de Materiais

2016-07-01

This article presents the results of molecular dynamics simulation of Cu{sub 60}Zr{sub 32.5}Ti{sub 7.5} alloy through the open source code LAMMPS. Amorphous samples were produced by quenching the metallic molten from 2300K to 200K at cooling rates of 50, 5 and 0.5K/ps. The pair distribution functions of both the liquid and solid were calculated and compared at different temperatures. The topology of short-range order was analyzed using the Voronoi tessellation method, which determined the presence of Cu-centered icosahedral clusters as the prevailing in the amorphous state at 300K. Moreover, the sample was submitted to uniaxial tensile tests at strain rate of 10ps{sup -1}, in order to investigate the mechanical behavior of the metallic glass. The result of the stress-strain curve showed that applied loads lead to the plastic regime. However, the presences of shear bands, typical in the experimental testing, were not observed. Moreover, the evolution of the viscosity above the glass transition temperature and the fragility of the alloy were determined. The solidus and liquidus temperatures were determined and a good agreement with experimental data was found. (author)

A molecular dynamics analysis of internal friction effects on the plasticity of Zr65Cu35 metallic glass

International Nuclear Information System (INIS)

Feng, Shidong; Qi, Li; Zhao, Fengli; Pan, Shaopeng; Li, Gong; Ma, Mingzhen; Liu, Riping

2015-01-01

Highlights: • Effects of internal friction on plasticity is investigated at the atomic level. • The simulations allow reproduction of images of internal friction evolution. • The simulation results are in good agreement with experiments and theories. • This simulation can predict the deformation mode with different internal friction. - Abstract: The effects of internal friction (IF) on Zr 65 Cu 35 metallic glass plasticity are investigated through molecular dynamics simulations. Results show that the Voronoi polyhedron 〈0, 3, 6, 3〉 increases as IF increases, thereby effectively inhibiting localized deformation and improving metallic glass plasticity. The simulations allow reproduction of images of IF evolution in metallic glasses subjected to isothermal annealing at 730 K and 850 K respectively, which can help explain the experimental observations. IF could be adjusted by selecting suitable annealing temperatures and cooling rates. The results of this work provide a strong foundation for future metallic glass designs

In vitro corrosion and biocompatibility screening of sputtered Ti{sub 40}Cu{sub 36}Pd{sub 14}Zr{sub 10} thin film metallic glasses on steels

Energy Technology Data Exchange (ETDEWEB)

Subramanian, B., E-mail: subramanianb3@gmail.com

2015-02-01

The growth of multi-component thin film metallic glasses (TFMGs) of Ti{sub 40}Cu{sub 36}Pd{sub 14}Zr{sub 10} (at.%) alloys fabricated using magnetron sputtering on bioimplantable 316L stainless steel substrates has been investigated. The vapor–solid quenching during sputtering enables the amorphous phases to be formed. The amorphous films consist of a single glassy phase, as evidenced by a broad hump and no detectable crystalline peaks as observed from XRD and selective area electron diffraction (SAED) patterns. The average surface roughness (Ra) of the coated film as observed from AFM was 0.3 nm. Nanohardness of about 7.7 GPa and Young's modulus of 110 GPa were measured from nanoindentation analysis. The potentiodynamic polarization and impedance measurements showed that coated stainless steel substrates have higher corrosion resistance compared to uncoated SS substrate in simulated body fluid (SBF) solution. The cytotoxicity studies using L929 fibroblast cells showed that these coatings were non-cytotoxic in nature. The interactions between the coated surface and bacteria were investigated by agar diffusion method, solution suspension and wet interfacial contact methods. - Highlights: • Ti-based TFMG coated specimen showed superior corrosion resistance. • Ti-based TFMG coated SS 316L specimen was non-cytotoxic in nature. • Antimicrobial activity of Ti-based TFMG was noticed.

Cavitation resistance of surface composition "Steel-Ni-TiNi-TiNiZr-cBNCo", formed by High-Velocity Oxygen-Fuel spraying

Science.gov (United States)

Blednova, Zh. M.; Dmitrenko, D. V.; Balaev, E. U. O.

2018-01-01

The object of the study is a multilayered surface composition "Steel - a Multicomponent material with Shape Memory Effect - a wear-resistant layer" under conditions of cavitation effects in sea water. Multicomponent TiNi-based coatings with addition of alloying elements such as Zr in an amount up to 10% mass, allow to create a composite material with a gradient of properties at the interface of layers, which gives new properties to coatings and improves their performance significantly. The use of materials with shape memory effect (SME) as surface layers or in the composition of surface layered compositions allows to provide an effective reaction of materials to the influence of external factors and adaptation to external influences. The surface composite layer cBN-10%Co has high hardness and strength, which ensures its resistance to shock cyclic influences of collapsing caverns. The increased roughness of the surface of a solid surface composite in the form of strong columnar structures ensures the crushing of vacuum voids, redistributing their effect on the entire surface, and not concentrating them in certain zones. In addition, the gradient structure of the multilayer composite coating TiNi-Ti33Ni49Zr18-cBN-10%Co Co makes it possible to create conditions for the relaxation of stresses created by the variable impact load of cavitation caverns and the manifestation of compensating internal forces due to thermo-elastic martensitic transformations of SME materials. The cavitation resistance of the coating TiNi-Ti33Ni49Zr18-cBN-10%Co according to the criterion of mass wear is 15-20 times higher than that of the base material without coating and 10-12 times higher than that of the TiNi-TiNiZr coating. The proposed architecture of the multifunctional gradient composition, "steel-Ni-TiNi- Ti33Ni49Zr18-cBN-10%Co", each layer of which has its functional purpose, allows to increase the service life of parts operating under conditions of cavitation-fatigue loading in

Thin and Flexible Fe-Si-B/Ni-Cu-P Metallic Glass Multilayer Composites for Efficient Electromagnetic Interference Shielding.

Science.gov (United States)

Zhang, Jijun; Li, Jiawei; Tan, Guoguo; Hu, Renchao; Wang, Junqiang; Chang, Chuntao; Wang, Xinmin

2017-12-06

Thin and flexible materials that can provide efficient electromagnetic interference (EMI) shielding are urgently needed, especially if they can be easily processed and withstand harsh environments. Herein, layer-structured Fe-Si-B/Ni-Cu-P metallic glass composites have been developed by simple electroless plating Ni-Cu-P coating on commercial Fe-Si-B metallic glasses. The 0.1 mm-thick composite shows EMI shielding effectiveness of 40 dB over the X-band frequency range, which is higher than those of traditional metals, metal oxides, and their polymer composites of larger thickness. Most of the applied electromagnetic waves are proved to be absorbed rather than bounced back. This performance originates from the combination of a superior soft magnetic property, excellent electrical conductivity, and multiple internal reflections from multilayer composites. In addition, the flexible composites also exhibit good corrosion resistance, high thermal stability, and excellent tensile strength, making them suitable for EMI shielding in harsh chemical or thermal environments.

Hot Embossing of Zr-Based Bulk Metallic Glass Micropart Using Stacked Silicon Dies

Directory of Open Access Journals (Sweden)

Zhijing Zhu

2015-01-01

Full Text Available We demonstrated hot embossing of Zr65Cu17.5Ni10Al7.5 bulk metallic glass micropart using stacked silicon dies. Finite element simulation was carried out, suggesting that it could reduce the stress below 400 MPa in the silicon dies and enhance the durability of the brittle silicon dies when using varying load mode (100 N for 60 s and then 400 N for 60 s compared with using constant load mode (200 N for 120 s. A micropart with good appearance was fabricated under the varying load, and no silicon die failure was observed, in agreement with the simulation. The amorphous state of the micropart was confirmed by differential scanning calorimeter and X-ray diffraction, and the nanohardness and Young’s modulus were validated close to those of the as-cast BMG rods by nanoindentation tests. The results proved that it was feasible to adopt the varying load mode to fabricate three-dimensional Zr-based bulk metallic glass microparts by hot embossing process.

Evolution of the electrical properties of amorphous Ni24Zr76 and Ni35Ti65 as a result of structural relaxation and crystallization

International Nuclear Information System (INIS)

Pelletier, J.M.; Fouquet, F.; Hillairet, J.

1986-01-01

Experimental results are given for the resistivity and the thermopower of two metallic glasses, Ni 24 Zr 76 and Ni 35 Ti 65 , together with the temperature dependences of these physical parameters, between 4 K (or 78 K) and crystallization temperature. In the as-quenched state the observed profiles are in qualitative agreement with the Mooij empirical law, but they agree only in part with the Ziman theory. The modifications which occur in response to successive thermal treatments are analyzed in terms of structural relaxation and crystallization processes. As expected the respective evolutions of the two electrical properties studied are found to be very closely related. It is shown that they can adequately be used to monitor the evolution of the volume fraction of crystallinity during the aging of amorphous metallic alloys. (author)

Structural behavior of Pd40Cu30Ni10P20 bulk metallic glass below and above the glass transition

DEFF Research Database (Denmark)

Mattern, N.; Hermann, H.; Roth, S.

2003-01-01

The thermal behavior of the structure of Pd40Cu30Ni10P20 bulk metallic glass has been investigated in situ through the glass transition by means of high-temperature x-ray synchrotron diffraction. The dependence of the x-ray structure factor S(q) of the Pd40Cu30Ni10P20 glass on temperature follows...... the Debye theory up to the glass transition with a Debye temperature theta=296 K. Above the glass transition temperature T-g, the temperature dependence of S(q) is altered, pointing to a continuous development of structural changes in the liquid with temperature. The atomic pair correlation functions g......(r) indicate changes in short-range-order parameters of the first and the second neighborhood with temperature. The temperature dependence of structural parameters is different in glass and in supercooled liquid, with a continuous behavior through the glass transition. The nearest-neighbor distance decreases...

Molecular dynamics simulation of nanotribology properties of CuZr metallic glasses

Energy Technology Data Exchange (ETDEWEB)

Wu, Cheng-Da [Chung Yuan Christian University, Department of Mechanical Engineering, Taoyuan City (China)

2016-04-15

The effects of scratch depth, scratch speed, and alloy composition on the mechanical deformation and nanotribology properties of CuZr metallic glasses are studied using molecular dynamics simulations based on the second-moment approximation of the many-body tight-binding potential. These effects are investigated in terms of atomic trajectories, slip vectors, friction force, normal force, and friction coefficient. The simulation results show that a few shear transformation zones independently develop at the contact area between the probe tip and the film. Pileup occurs in the nanoscratch process but not during nanoindentation at a depth of 2.4 nm. There are two areas on the surface where the atoms have high slip vector values during nanoscratching. These areas form due to the removal of atoms that piled up around the probe tip and those behind the probe tip, respectively. Both the friction force and the normal force increase with increasing scratch depth and scratch speed. Friction coefficients decrease with increasing scratch depth, scratch speed, and Zr content in films. (orig.)

Heating and structural disordering effects of the nonlinear viscous flow in a Zr55Al10Ni5Cu30 bulk metallic glass

International Nuclear Information System (INIS)

Kato, Hidemi; Inoue, Akihisa; Chen, H.S.

2003-01-01

The heat evolution of stress-induced structural disorder, ΔH s (ε), of a Zr 55 Al 10 Ni 5 Cu 30 bulk metallic glass (BMG) during compressive constant ram-velocity deformation at the glass transition region (T g =680 K) was deduced from in situ measurements of temperature change of the deforming sample. At the transition from the linear to nonlinear viscoelasticity, the behavior of viscosity change with strain, η(ε), is qualitatively consistent with the enthalpy evolution of the structural disordering, ΔH s (ε), but not with the temperature change, ΔT(ε). It is concluded that the initial softening deformation is due to the stress-induced structural disordering. The change in the nonlinearity, -log η-tilde ≡-log η /η N , is found to be proportional to the ΔH s and the slope of ΔH s (-log η-tilde) can be estimated to 400 J/mol, where η N is the Newtonian viscosity. On the other hand, the temperature raise, ΔT(ε), is pronouncedly delayed as compared with the η (ε) and ΔH s (ε) at the transition, but is determined by a product of stress and plastic strain-rate, σ·ε p , and is nearly proportional to it at the steady state. The slope of ΔT(σ·ε p ) can be estimated to 5.2x10 -2 K mol/W

In-situ ductile metal/bulk metallic glass matrix composites formed by chemical partitioning

Science.gov (United States)

Kim, Choong Paul; Hays, Charles C.; Johnson, William L.

2004-03-23

A composite metal object comprises ductile crystalline metal particles in an amorphous metal matrix. An alloy is heated above its liquidus temperature. Upon cooling from the high temperature melt, the alloy chemically partitions, forming dendrites in the melt. Upon cooling the remaining liquid below the glass transition temperature it freezes to the amorphous state, producing a two-phase microstructure containing crystalline particles in an amorphous metal matrix. The ductile metal particles have a size in the range of from 0.1 to 15 micrometers and spacing in the range of from 0.1 to 20 micrometers. Preferably, the particle size is in the range of from 0.5 to 8 micrometers and spacing is in the range of from 1 to 10 micrometers. The volume proportion of particles is in the range of from 5 to 50% and preferably 15 to 35%. Differential cooling can produce oriented dendrites of ductile metal phase in an amorphous matrix. Examples are given in the Zr--Ti--Cu--Ni--Be alloy bulk glass forming system with added niobium.

Electrochemical characterization of Zr-based thin film metallic glass in hydrochloric aqueous solution

International Nuclear Information System (INIS)

Chuang, Ching-Yen; Liao, Yi-Chia; Lee, Jyh-Wei; Li, Chia-Lin; Chu, Jinn P.; Duh, Jenq-Gong

2013-01-01

Recently thin film metallic glass represents a class of promising engineering materials for structural applications. In this work, the Zr-based thin film metallic glass (TFMG) was fabricated on the Si and AISI 420 substrates using a Zr–Cu–Ni–Al alloy and pure Zr metal targets by a pulsed DC magnetron sputtering system. The chemical compositions, crystalline structures, microstructures and corrosion behavior in hydrochloric (HCl) aqueous solutions of Zr-based TFMGs were investigated. The results showed that the surface morphologies of Zr-based TFMG were very smooth. A compact and dense structure without columnar structure was observed. The amorphous structure of Zr-based TFMG was characterized by the X-ray diffractometer and transmission electron microscopy analyses. After the potentiodynamic polarization test, the better corrosion resistance was achieved for the Zr-based TFMG coated AISI 420 in 1 mM HCl aqueous solution. Based on the surface morphologies and chemical analysis results of the corroded surfaces, the pitting, crevice corrosion and filiform corrosion were found. The corrosion mechanisms of the Zr-based TFMG were discussed in this work. - Highlights: ► Zr-based thin film metallic glass with amorphous structure. ► Better corrosion resistance of Zr-based thin film metallic glass observed. ► Pitting, crevice and filiform corrosion reactions revealed. ► The Cu-rich corrosion products found in the pit. ► Nanowire and flaky corrosion products formed adjacent to the filiform corrosion path

On the kinetic and thermodynamic fragility of the Pt{sub 60}Cu{sub 16}Co{sub 2}P{sub 22} and Pt{sub 57.3}Cu{sub 14.6}Ni{sub 5.3}P{sub 22.8} bulk metallic glasses

Energy Technology Data Exchange (ETDEWEB)

Gallino, Isabella, E-mail: i.gallino@mx.uni-saarland.de [Saarland University, Department of Materials Science and Engineering, Campus C6.3, 66123 Saarbruecken (Germany); Gross, Oliver [Saarland University, Department of Materials Science and Engineering, Campus C6.3, 66123 Saarbruecken (Germany); Dalla Fontana, Giulia [Department of Chemistry IFM and NIS, University of Torino, V. Giuria 7, 10125 Torino (Italy); Evenson, Zach; Busch, Ralf [Saarland University, Department of Materials Science and Engineering, Campus C6.3, 66123 Saarbruecken (Germany)

2014-12-05

Highlights: • The studied Pt–Cu–(Ni,Co)–P glasses are more fragile than Zr-based alloys. • They show large increases in the C{sub p} at T{sub g} and small barriers for cooperative rearrangements of atoms. • They have fragility parameters among the lowest reported for BMG systems (D{sup *} = 10–12). • They crystallize into a state that melts with distinctly high entropy of fusion. • The microscopic origin of their fragility seems different than that for Zr- and Pd-based BMGs. - Abstract: The investigations in this study focus on bulk metallic glass (BMG) alloy families based on noble metals like Pt, which are more kinetically fragile than Zr-based BMG systems. Thermophysical properties have been investigated by calorimetry and thermal mechanical analyses for the determination of the specific heat capacity and viscosity, respectively. For the Pt{sub 60}Cu{sub 16}Co{sub 2}P{sub 22} and Pt{sub 57.3}Cu{sub 14.6}Ni{sub 5.3}P{sub 22.8} BMG compositions consistent Vogel–Fulcher–Tammann (VFT) fits of the viscosity measurements are established, and the temperature dependence of the configurational entropy is calculated from thermodynamic data. Fits to the Adam–Gibbs equation are performed using this configurational entropy change. Their fragile nature is compared to that of Zr-based alloys in terms of structural considerations.

Microstructural evolution in decomposition of amorphous Zr41Ti14Cu12.5Ni10Be22.5 alloy, as investigated by small-angle neutron scattering

International Nuclear Information System (INIS)

Liu Junming; Hahn-Meitner-Inst. Berlin, Bereich, NM; Nanjing Univ.

1997-01-01

Small angle neutron scattering (SANS) has been applied to investigate decomposition kinetics and microstructural evolution in amorphous Zr 41 Ti 14 Cu 12.5 Ni 10 Be 22.5 . It is detected that immediately after the alloy is submitted into the supercooled liquid range, phase separation develops rapidly in the early stage, leaving a sluggish coarsening stage. The decomposed alloy finally achieves a roughly regular microstructure which consists of one particle-like supercooled liquid phase embedded in the similarly disordered matrix. The morphology of the particles as a function of time is evaluated, predicting a bar-like pattern. Strong temperature dependence of the phase separation is observed. (orig.)

Glass-forming ability and crystallization behavior of some binary and ternary Ni-based glassy alloys

International Nuclear Information System (INIS)

Louzguine-Luzgin, Dmitri V.; Louzguina-Luzgina, Larissa V.; Xie Guoqiang; Li Song; Zhang Wei; Inoue, Akihisa

2008-01-01

The purpose of the current paper is to study the influence of Ti, V, Nb, Al, Sn and Pd additions on the glass-forming ability, formation of a supercooled liquid region and a devitrification process of some Ni-Zr glassy alloys as well as to compare the results with those obtained for similar Cu-based alloys studied earlier. The Ni-based glassy alloys were investigated by using X-ray diffraction, differential scanning and isothermal calorimetries. Although the studied Ni-based alloys showed high values of the reduced glass-transition temperature of about 0.6, their glass-forming ability is quite low. This fact may be explained by low stability of the supercooled liquid against crystallization and formation of the equilibrium intermetallic compounds with a high growth rate compared to those observed in similar Cu-based alloys studied earlier. Relatively low thermal conductivity of Ni-based alloys is also found to be another factor limiting their glass-forming ability

Improving High-Temperature Tensile and Low-Cycle Fatigue Behavior of Al-Si-Cu-Mg Alloys Through Micro-additions of Ti, V, and Zr

Science.gov (United States)

Shaha, S. K.; Czerwinski, F.; Kasprzak, W.; Friedman, J.; Chen, D. L.

2015-07-01

High-temperature tensile and low-cycle fatigue tests were performed to assess the influence of micro-additions of Ti, V, and Zr on the improvement of the Al-7Si-1Cu-0.5Mg (wt pct) alloy in the as-cast condition. Addition of transition metals led to modification of microstructure where in addition to conventional phases present in the Al-7Si-1Cu-0.5Mg base, new thermally stable micro-sized Zr-Ti-V-rich phases Al21.4Si4.1Ti3.5VZr3.9, Al6.7Si1.2TiZr1.8, Al2.8Si3.8V1.6Zr, and Al5.1Si35.4Ti1.6Zr5.7Fe were formed. The tensile tests showed that with increasing test temperature from 298 K to 673 K (25 °C to 400 °C), the yield stress and tensile strength of the present studied alloy decreased from 161 to 84 MPa and from 261 to 102 MPa, respectively. Also, the studied alloy exhibited 18, 12, and 5 pct higher tensile strength than the alloy A356, 354 and existing Al-Si-Cu-Mg alloy modified with additions of Zr, Ti, and Ni, respectively. The fatigue life of the studied alloy was substantially longer than those of the reference alloys A356 and the same Al-7Si-1Cu-0.5Mg base with minor additions of V, Zr, and Ti in the T6 condition. Fractographic analysis after tensile tests revealed that at the lower temperature up to 473 K (200 °C), the cleavage-type brittle fracture for the precipitates and ductile fracture for the matrix were dominant while at higher temperature fully ductile-type fracture with debonding and pull-out of cracked particles was identified. It is believed that the intermetallic precipitates containing Zr, Ti, and V improve the alloy performance at increased temperatures.

Development of Fe-B Based Bulk Metallic Glasses: Morphology of Residual Phases in Fe50Ni16Mo6B18Zr10 Glass

Directory of Open Access Journals (Sweden)

Tiburce A. Aboki

2013-04-01

Full Text Available Iron-boron based bulk metallic glasses (BMG development has been initiated using Fe40Ni38Mo4B18 as precursor. Addition of zirconium up to 10 atomic % along with the reduction of Ni proportion improves the glass forming ability (GFA, which is optimum when Ni is suppressed in the alloy. However melting instability occurred during the materials fabrication resulting in the formation of residual crystalline phases closely related to the amorphous phase. Microstructure study shows an evolution from amorphous structure to peculiar acicular structure, particularly for Fe50Ni16Mo6B18Zr10, suggesting the amorphous structure as interconnected atomic sheets like “atomic mille feuilles” whose growth affects the alloys’ GFA.

Microstructural Characteristics and Mechanical Properties of an Electron Beam-Welded Ti/Cu/Ni Joint

Science.gov (United States)

Zhang, Feng; Wang, Ting; Jiang, Siyuan; Zhang, Binggang; Feng, Jicai

2018-05-01

Electron beam welding experiments of TA15 titanium alloy to GH600 nickel superalloy with and without a copper sheet interlayer were carried out. Surface appearance, microstructure and phase constitution of the joint were examined by optical microscopy, scanning electron microscopy and x-ray diffraction analysis. Mechanical properties of Ti/Ni and Ti/Cu/Ni joint were evaluated based on tensile strength and microhardness tests. The results showed that cracking occurred in Ti/Ni electron beam weldment for the formation of brittle Ni-Ti intermetallics, while a crack-free electron beam-welded Ti/Ni joint can be obtained by using a copper sheet as filler metal. The addition of copper into the weld affected the welding metallurgical process of the electron beam-welded Ti/Ni joint significantly and was helpful for restraining the formation of Ti-Ni intermetallics in Ti/Ni joint. The microstructure of the weld was mainly characterized by a copper-based solid solution and Ti-Cu interfacial intermetallic compounds. Ti-Ni intermetallic compounds were almost entirely suppressed. The hardness of the weld zone was significantly lower than that of Ti/Ni joint, and the tensile strength of the joint can be up to 282 MPa.

Crystallization behavior and the thermal properties of Zr63Al7.5Cu17.5Ni10B2 bulk amorphous alloy

International Nuclear Information System (INIS)

Jang, J.S.C.; Chang, L.J.; Jiang, Y.T.; Wong, P.W.

2003-01-01

The ribbons of amorphous Zr 63 Al 7.5 Cu 17.5 Ni 10 B 2 alloys with 0.1 mm thickness were prepared by melt spinning method. The thermal properties and micro structural development during the annealing of amorphous alloy have been investigated by a combination of differential thermal analysis, differential scanning calorimetry, high-temperature optical microscope, X-ray diffractometry and TEM. The glass transition temperature for the Zr 63 Al 7.5 Cu 17.5 Ni 10 B 2 alloys are measured about 645 K (372 C). This alloy also obtains a large temperature interval ΔT x about 63 K. Meanwhile, the calculated T rg for Zr 63 Al 7.5 Cu 17.5 Ni 10 B 2 alloy presents the value of 0.57. The activation energy of crystallization for the alloy Zr 63 Al 7.5 Cu 17.5 Ni 10 B 2 was about 370± 10 kJ/mole as determined by the Kissinger and Avrami plot, respectively. These values are about 20% higher than the activation energy of crystallization for the Zr 65 Al 7.5 Cu 17.5 Ni 10 alloy (314 kJ/mol.). This implies that the boron additions exhibit the effect of improving the thermal stability for the Zr-based alloy. The average value of the Avrami exponent n were calculated to be 1.75±0.15 for Zr 63 Al 7.5 Cu 17.5 Ni 10 B 2 alloy. This indicates that this alloy presents a crystallization process with decreasing nucleation rate. (orig.)

Amorphous-to-Cu51Zr14 phase transformation in Cu60Ti20Zr20 alloy

International Nuclear Information System (INIS)

Cao, Q P; Zhou, Y H; Horsewell, A; Jiang, J Z

2003-01-01

The kinetics of an amorphous-to-Cu 51 Zr 14 phase transformation in an as-cast Cu 60 Ti 20 Zr 20 rod have been investigated by differential scanning calorimetry. The relative volume fractions of the transferred crystalline phase as a function of annealing time, obtained at 713, 716, 723, 728, and 733 K, have been analysed in detail using 14 nucleation and growth models together with the JMA model. A time-dependent nucleation process is revealed. A steady-state nucleation rate of the order of 10 22 - 10 23 nuclei m -3 s -1 in the temperature range 713-733 K and an activation energy of the order of 550 kJmol -1 for the phase transformation in the as-cast Cu 60 Ti 20 Zr 20 rod were detected, for which some possible reasons are suggested

Grain Refinement and Mechanical Properties of Cu-Cr-Zr Alloys with Different Nano-Sized TiCp Addition.

Science.gov (United States)

Zhang, Dongdong; Bai, Fang; Wang, Yong; Wang, Jinguo; Wang, Wenquan

2017-08-08

The TiC p /Cu master alloy was prepared via thermal explosion reaction. Afterwards, the nano-sized TiC p /Cu master alloy was dispersed by electromagnetic stirring casting into the melting Cu-Cr-Zr alloys to fabricate the nano-sized TiC p -reinforced Cu-Cr-Zr composites. Results show that nano-sized TiC p can effectively refine the grain size of Cu-Cr-Zr alloys. The morphologies of grain in Cu-Cr-Zr composites changed from dendritic grain to equiaxed crystal because of the addition and dispersion of nano-sized TiC p . The grain size decreased from 82 to 28 μm with the nano-sized TiC p content. Compared with Cu-Cr-Zr alloys, the ultimate compressive strength (σ UCS ) and yield strength (σ 0.2 ) of 4 wt% TiC p -reinforced Cu-Cr-Zr composites increased by 6.7% and 9.4%, respectively. The wear resistance of the nano-sized TiCp-reinforced Cu-Cr-Zr composites increased with the increasing nano-sized TiCp content. The wear loss of the nano-sized TiC p -reinforced Cu-Cr-Zr composites decreased with the increasing TiC p content under abrasive particles. The eletrical conductivity of Cu-Cr-Zr alloys, 2% and 4% nano-sized TiCp-reinforced Cu-Cr-Zr composites are 64.71% IACS, 56.77% IACS and 52.93% IACS, respectively.

Hydrogen-induced high damping of bulk metallic glasses

International Nuclear Information System (INIS)

Hasegawa, M.

2009-01-01

There are two important topics concerned with the recent researches on the damping materials of hydrogenated metallic glasses (HMGs). One is the mechanism of the high hydrogen-induced internal friction of HMGs. The other is the materials processing of 'bulk' HMGs for engineering. This article describes the summary of our recent studies on these topics. The first one is closely related to the local structure of the metallic glasses. Therefore, our recent results on the intermediate-range local structure of the simple two Zr-based metallic glasses are described, which has been clarified by the Voronoi analysis using the experimental data of the neutron diffraction measurements. The hydrogen-induced internal friction of HMGs is also discussed on the basis of these recent results of the local structure of the metallic glasses. In terms of the second topic, the first successful preparation of heavily hydrogenated Zr-based bulk HMG rods without hydrogen-induced surface embrittlement is described. They are prepared by a powder-compact-melting and liquid-casting process using Zr-Al-Ni-Cu metallic glass and ZrH 2 powders as the starting materials. It has been found that they have high damping properties.

Electron beam welding of dissimilar metals

International Nuclear Information System (INIS)

Metzger, G.; Lison, R.

1976-01-01

Thirty-three two-memeber combinations of dissimilar metals were electron beam welded as square-groove butt joints in 0.08 and 0.12 in. sheet material. Many joints were ''braze welded'' by offsetting the electron beam about 0.02 in. from the butt joint to achieve fusion of the lower melting point metal, but no significant fusion of the other member of the pair. The welds were evaluated by visual and metallographic examination, transverse tensile tests, and bend tests. The welds Ag/Al, Ag/Ni15Cr7Fe, Cu/Ni15Cr7Fe, Cu/V, Cu20Ni/Ni15Cr7Fe, Fe18Cr8Ni/Ni, Fe18Cr8Ni/Ni15Cr7Fe, Nb/Ti, Nb/V, Ni/Ni15Cr7Fe, and Cb/V10Ti were readily welded and weld properties were excellent. Others which had only minor defects included the Ag/Cu20Ni, Ag/Ti, Ag/V, Cu/Fe18Cr8Ni, Cu/V10Ti, Cu20Ni/Fe18Cr8Ni, and Ti/Zr2Sn welds. The Cu/Ni weld had deep undercut, but was in other respects excellent. The mechanical properties of the Ag/Fe18Cr8Ni weld were poor, but the defect could probably be corrected. Difficulty with cracking was experienced with the Al/Ni and Fe18Cr8Ni/V welds, but sound welds had excellent mechanical properties. The remaining welds Al-Cu, Al/Cu20Ni, Al/Fe18Cr8Ni, Al/Ni15Cr7Fe, Cu20Ni/V, Cu20Ni/V10Ti, Cb/Zr2Sn, Ni/Ti, Ni15Cr7Fe/V, Ni15Cr7Fe/V10Ti, and Ti/V were unsuccessful, due to brittle phases, primarily at the weld metal-base metal interface. In addition to the two-member specimens, several joints were made by buttering. Longitudinal weld specimens of the three-member combination Al/Ni/Fe18Cr8Ni and the five member combination Fe18Cr8Ni/V/Cb/Ti/Zr2Sn showed good tensile strength and satisfactory elongation. 6 tables, 16 figures

Effect of Si addition on glass-forming ability and mechanical properties of Cu-Zr-Al bulk metallic glass

International Nuclear Information System (INIS)

Malekan, M.; Shabestari, S.G.; Zhang, W.; Seyedein, S.H.; Gholamipour, R.; Makino, A.; Inoue, A.

2010-01-01

Research highlights: The Cu 50 Zr 43 Al 7 alloy has a surprising GFA, and the glassy rods with diameter of 10 mm have been produced in this research. It has not been reported that the Cu-based glassy rods (Cu ≥ 50 at.%) to be produced with the critical diameter greater than 10 mm. The novelty of this research is that the glass formation has been improved and the critical diameter increased to 12 mm for the alloy having x = 1 with the addition of Si. Different criteria are used to evaluate the influence of Si content on the GFA, and the possible mechanisms involved in the achievement of this GFA are also discussed. - Abstract: The effect of Si addition on the glass-forming ability (GFA) and mechanical properties of (Cu 50 Zr 43 Al 7 ) 100-x Si x (x = 0, 0.5, 1, 1.5 and 2 at.%) alloys were investigated. The GFA of Cu 50 Zr 43 Al 7 alloy is improved by addition of a small amount of Si, and the critical diameter for glass formation increases from 10 mm for the alloy with x = 0-12 mm for the alloy with x = 1 when prepared using copper mold casting. Different criteria are used to evaluate the influence of Si content on the GFA, and the possible mechanisms involved in the achievement of this GFA are also discussed. In the uniaxial compression, the bulk glassy alloys exhibit a limited plastic strain of less than 1%, but the compressive fracture strength and Young's modulus were obtained in high values of 1969-2129 MPa and 101-144 GPa, respectively. Fracture surface and shear bands of samples were studied by using scanning electron microscopy (SEM).

Magnetron sputtered Cu{sub 3}N/NiTiCu shape memory thin film heterostructures for MEMS applications

Energy Technology Data Exchange (ETDEWEB)

Kaur, Navjot; Choudhary, Nitin [Indian Institute of Technology Roorkee, Roorkee, Functional Nanomaterials Research Lab, Department of Physics and Centre of Nanotechnology (India); Goyal, Rajendra N. [Indian Institute of Technology, Roorkee, Department of Chemistry (India); Viladkar, S. [Indian Institute of Technology Roorkee, Roorkee, Functional Nanomaterials Research Lab, Department of Physics and Centre of Nanotechnology (India); Matai, I.; Gopinath, P. [Indian Institute of Technology, Roorkee, Centre for Nanotechnology (India); Chockalingam, S. [Indian Institute of Technology, Guwahati, Department of Biotechnology (India); Kaur, Davinder, E-mail: dkaurfph@iitr.ernet.in [Indian Institute of Technology Roorkee, Roorkee, Functional Nanomaterials Research Lab, Department of Physics and Centre of Nanotechnology (India)

2013-03-15

In the present study, for the first time, Cu{sub 3}N/NiTiCu/Si heterostructures were successfully grown using magnetron sputtering technique. Nanocrystalline copper nitride (Cu{sub 3}N with thickness {approx}200 nm) thin films and copper nanodots were subsequently deposited on the surface of 2-{mu}m-thick NiTiCu shape memory thin films in order to improve the surface corrosion and nickel release properties of NiTiCu thin films. Interestingly, the phase transformation from martensite phase to austenite phase has been observed in Cu{sub 3}N/NiTiCu heterostructures with corresponding change in texture and surface morphology of top Cu{sub 3}N films. Field emission scanning electron microscopy and atomic force microscope images of the heterostructures reveals the formation of 20-nm-sized copper nanodots on NiTiCu surface at higher deposition temperature (450 Degree-Sign C) of Cu{sub 3}N. Cu{sub 3}N passivated NiTiCu films possess low corrosion current density with higher corrosion potential and, therefore, better corrosion resistance as compared to pure NiTiCu films. The concentration of Ni released from the Cu{sub 3}N/NiTiCu samples was observed to be much less than that of pure NiTiCu film. It can be reduced to the factor of about one-ninth after the surface passivation resulting in smooth, homogeneous and highly corrosion resistant surface. The antibacterial and cytotoxicity of pure and Cu{sub 3}N coated NiTiCu thin films were investigated through green fluorescent protein expressing E. coli bacteria and human embryonic kidney cells. The results show the strong antibacterial property and non cytotoxicity of Cu{sub 3}N/NiTiCu heterostructure. This work is of immense technological importance due to variety of BioMEMS applications.

Tensile behavior of Cu50Zr50 metallic glass nanowire with a B2 crystalline precipitate

Science.gov (United States)

Sepulveda-Macias, Matias; Amigo, Nicolas; Gutierrez, Gonzalo

2018-02-01

A molecular dynamics study of the effect of a single B2-CuZr precipitate on the mechanical properties of Cu50Zr50 metallic glass nanowires is presented. Four different samples are considered: three with a 2, 4 and 6 nm radii precipitate and a precipitate-free sample. These systems are submitted to uniaxial tensile test up to 25% of strain. The interface region between the precipitate and the glass matrix has high local atomic shear strain, activating shear transformation zones, which concentrates in the neighborhood of the precipitate. The plastic regime is dominated by necking, and no localized shear band is observed for the samples with a 4 and 6 nm radii precipitate. In addition, the yield stress decreases as the size of the precipitate increases. Regarding the precipitate structure, no martensitic phase transformation is observed, since neither the shear band hit the precipitate nor the stress provided by the tensile test is enough to initiate the transformation. It is concluded that, in contrast to the case when multiple precipitates are present in the sample, a single precipitate concentrates the shear strain around its surface, eventually causing the failure of the nanowire.

Creep behaviour of a casting titanium carbide reinforced AlSi12CuNiMg piston alloy at elevated temperatures; Hochtemperaturkriechverhalten der schmelzmetallurgisch hergestellten dispersionsverstaerkten Kolbenlegierung AlSi12CuNiMg

Energy Technology Data Exchange (ETDEWEB)

Michel, S.; Scholz, A. [Zentrum fuer Konstruktionswerkstoffe, TU Darmstadt (Germany); Tonn, B. [Institut fuer Metallurgie, TU Clausthal (Germany); Zak, H.

2012-03-15

This paper deals with the creep behaviour of the titanium carbide reinforced AlSi12CuNiMg piston alloy at 350 C and its comparison to the conventional AlSi12Cu4Ni2MgTiZr piston alloy. With only 0,02 vol-% TiC reinforcement the creep strength and creep rupture strength of the AlSi12CuNiMg piston alloy are significantly improved and reach the level of the expensive AlSi12Cu4Ni2MgTiZr alloy. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Formation and Applications of Bulk Glassy Alloys in Late Transition Metal Base System

International Nuclear Information System (INIS)

Inoue, Akihisa; Shen Baolong

2006-01-01

This paper reviews our recent results of the formation, fundamental properties, workability and applications of late transition metal (LTM) base bulk glassy alloys (BGAs) developed since 1995. The BGAs were obtained in Fe-(Al,Ga)-(P,C,B,Si), Fe-(Cr,Mo)-(C,B), Fe-(Zr,Hf,Nb,Ta)-B, Fe-Ln-B(Ln=lanthanide metal), Fe-B-Si-Nb and Fe-Nd-Al for Fe-based alloys, Co-(Ta,Mo)-B and Co-B-Si-Nb for Co-based alloys, Ni-Nb-(Ti,Zr)-(Co,Ni) for Ni-based alloys, and Cu-Ti-(Zr,Hf), Cu-Al-(Zr,Hf), Cu-Ti-(Zr,Hf)-(Ni,Co) and Cu-Al-(Zr,Hf)-(Ag,Pd) for Cu-based alloys. These BGAs exhibit useful properties of high mechanical strength, large elastic elongation and high corrosion resistance. In addition, Fe- and Co-based glassy alloys have good soft magnetic properties which cannot be obtained for amorphous and crystalline type magnetic alloys. The Fe- and Ni-based BGAs have already been used in some application fields. These LTM base BGAs are promising as new metallic engineering materials

Alloy with metallic glass and quasi-crystalline properties

Science.gov (United States)

Xing, Li-Qian; Hufnagel, Todd C.; Ramesh, Kaliat T.

2004-02-17

An alloy is described that is capable of forming a metallic glass at moderate cooling rates and exhibits large plastic flow at ambient temperature. Preferably, the alloy has a composition of (Zr, Hf).sub.a Ta.sub.b Ti.sub.c Cu.sub.d Ni.sub.e Al.sub.f, where the composition ranges (in atomic percent) are 45.ltoreq.a.ltoreq.70, 3.ltoreq.b.ltoreq.7.5, 0.ltoreq.c.ltoreq.4, 3.ltoreq.b+c.ltoreq.10, 10.ltoreq.d.ltoreq.30, 0.ltoreq.e.ltoreq.20, 10.ltoreq.d+e.ltoreq.35, and 5.ltoreq.f.ltoreq.15. The alloy may be cast into a bulk solid with disordered atomic-scale structure, i.e., a metallic glass, by a variety of techniques including copper mold die casting and planar flow casting. The as-cast amorphous solid has good ductility while retaining all of the characteristic features of known metallic glasses, including a distinct glass transition, a supercooled liquid region, and an absence of long-range atomic order. The alloy may be used to form a composite structure including quasi-crystals embedded in an amorphous matrix. Such a composite quasi-crystalline structure has much higher mechanical strength than a crystalline structure.

Degradation of Zr-based bulk metallic glasses used in load-bearing implants: A tribocorrosion appraisal.

Science.gov (United States)

Zhao, Guo-Hua; Aune, Ragnhild E; Mao, Huahai; Espallargas, Nuria

2016-07-01

Owing to the amorphous structure, Bulk Metallic Glasses (BMGs) have been demonstrating attractive properties for potential biomedical applications. In the present work, the degradation mechanisms of Zr-based BMGs with nominal compositions Zr55Cu30Ni5Al10 and Zr65Cu18Ni7Al10 as potential load-bearing implant material were investigated in a tribocorrosion environment. The composition-dependent micro-mechanical and tribological properties of the two BMGs were evaluated prior to the tribocorrosion tests. The sample Zr65-BMG with a higher Zr content exhibited increased plasticity but relatively reduced wear resistance during the ball-on-disc tests. Both BMGs experienced abrasive wear after the dry wear test under the load of 2N. The cross-sectional subsurface structure of the wear track was examined by Focused Ion Beam (FIB). The electrochemical properties of the BMGs in simulated body fluid were evaluated by means of potentiodynamic polarization and X-ray Photoelectron Spectroscopy (XPS). The spontaneous passivation of Zr-based BMGs in Phosphate Buffer Saline solution was mainly attributed to the highly concentrated zirconium cation (Zr(4+)) in the passive film. The tribocorrosion performance of the BMGs was investigated using a reciprocating tribometer equipped with an electrochemical cell. The more passive nature of the Zr65-BMG had consequently a negative influence on its tribocorrosion resistance, which induced the wear-accelerated corrosion and eventually speeded-up the degradation process. It has been revealed the galvanic coupling was established between the depassivated wear track and the surrounding passive area, which is the main degradation mechanism for the passive Zr65-BMG subjected to the tribocorrosion environment. Copyright © 2015 Elsevier Ltd. All rights reserved.

Fracture resistance of dental nickel–titanium rotary instruments with novel surface treatment: Thin film metallic glass coating

Directory of Open Access Journals (Sweden)

Chih-Wen Chi

2017-05-01

Conclusion: The novel surface treatment of Ti-Zr-B thin film metallic glass on dental NiTi rotary files can effectively improve the fatigue fracture resistance by offering a smooth coated surface with amorphous microstructure.

Magnetic and electronic properties of the Cu-substituted Weyl semimetal candidate ZrCo2Sn.

Science.gov (United States)

Kushwaha, S K; Wang, Zhijun; Kong, Tai; Cava, Robert

2018-01-04

We report that the partial substitution of Cu for Co has a significant impact on the magnetic properties of the Heusler-phase Weyl fermion candidate ZrCo₂Sn. Polycrystalline samples of ZrCo_2-xCu_xSn (x = 0.0 to 1.0) exhibited a linearly decreasing ferromagnetic transition temperature and similarly decreasing saturated magnetic moment on increasing Cu substitution x. Materials with Cu contents near x = 1 and several other quaternary materials synthesized at the same x (ZrCoT'Sn (T' = Rh, Pd, Ni)) display what appears to be non-ferromagnetic magnetization behavior with spin glass characteristics. Electronic structure calculations suggest that the half-metallic nature of unsubstituted ZrCo₂Sn is disrupted significantly by the Cu substitutions, leading to the breakdown of the magnetization vs. electron count guidelines usually followed by Heusler phases, and a more typical metallic non-spin-polarized electronic structure at high x. © 2018 IOP Publishing Ltd.

Resistance to He{sup 2+} irradiation damage in metallic glass Ta{sub 38}Ni{sub 62}

Energy Technology Data Exchange (ETDEWEB)

Hou, Wenjing [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116024 (China); Mei, Xianxiu, E-mail: xxmei@dlut.edu.cn [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116024 (China); Zhang, Xiaonan; Wang, Yingmin; Qiang, Jianbing [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116024 (China); Sun, Jianrong [Institute of Modern Physics, The Chinese Academy of Sciences, Lanzhou 730000 (China); Wang, Younian [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116024 (China)

2016-10-15

Highlights: • Metallic glass Ta{sub 38}Ni{sub 62} irradiated by different fluence of He{sup 2+} remained amorphous. • The helium bubble layer appeared at the end of ion range 1.01 μm away from surface. • Helium bubbles were larger in the layer center and reduced to top and bottom sides. • No significant damage appeared in the surface of metallic glass Ta{sub 38}Ni{sub 62}. • Ta{sub 38}Ni{sub 62} better resisted to He{sup 2+} irradiation than W and V{sub 87.5}Cr{sub 4.17}Ti{sub 4.17}Nb{sub 4.17}. - Abstract: Metallic glass Ta{sub 38}Ni{sub 62} strips, metallic W, and V{sub 87.5}Cr{sub 4.17}Ti{sub 4.17}Nb{sub 4.17} alloy were irradiated using a 500 keV He{sup 2+} ion beam at different fluence to compare the metallic glass resistance to irradiation. Metallic glass Ta{sub 38}Ni{sub 62} remained amorphous at different He{sup 2+} irradiation fluence. Transmission electron microscopy analysis revealed the presence of helium bubbles at the end of the range of helium ions in the metallic glass. No significant damage resulted in the metallic glass surface, and the root mean square roughness increased nonlinearly with the increase in fluence. At 1 × 10{sup 18} ions/cm{sup 2}, metallic W appeared in larger sunken areas on the surface and V{sub 87.5}Cr{sub 4.17}Ti{sub 4.17}Nb{sub 4.17} alloy experienced multi-layer flaking. The metallic glass Ta{sub 38}Ni{sub 62} resistance to He{sup 2+} ion beam irradiation was better than that of metallic W, and that of the V{sub 87.5}Cr{sub 4.17}Ti{sub 4.17}Nb{sub 4.17} alloy was the poorest.

A study on crystalline phases present in the as-solidified and crystallized microstructures in Zr53Cu21Al10Ni8Ti8 alloy

International Nuclear Information System (INIS)

Neogy, S.; Tewari, R.; Srivastava, D.; Dey, G.K.

2011-01-01

In the present study the as-solidified and crystallized microstructures of Zr 53 Cu 21 Al 10 Ni 8 Ti 8 alloy have been examined in detail. Solidification was carried out by melt spinning, suction casting and copper mould casting techniques. The last technique yielded a partially crystalline microstructure, whereas, the other two techniques resulted in amorphous microstructures. (author)

Study of inelastic deformation mechanisms in metal glass volume

International Nuclear Information System (INIS)

Bakaj, S.A.; Neklyudov, I.M.; Savchenko, V.I.; Ehkert, Yu.

2001-01-01

The results of investigations of the mechanical properties and internal friction of the bulk amorphous alloy Zr 53.5 Ti 5 Cu 17.5 Ni 14.6 Al 10.4 within the temperature range from the room temperature up to glass-transition temperature are reported. The yield stress and transition from homogeneous to inhomogeneous plastic deformation are investigated. The temperature dependence of low-frequency internal friction, Q -1 (T), in the amplitude-independent limit of oscillations is obtained. The temperature range within which the homogeneous plastic deformation is observed under compression stress is determined. The superplasticity of the amorphous alloy is revealed at the temperature which is 100K lower than the glass-transition temperature. The lowest temperature, at which the superplasticity is revealed, turns to be an edge of the temperature range where Q -1 (T) increases fast. The microscopic nature of the observed phenomena are interpreted on the base of the polycluster model of the metallic glasses

Origin of nondetectable x-ray diffraction peaks in nanocomposite CuTiZr alloys

DEFF Research Database (Denmark)

Jiang, Jianzhong; Kato, H.; Ohsuna, T.

2003-01-01

Microscopic structures of Cu60Ti10+xZr30-x (x=0 and 10) alloys have been investigated by transmission electron microscopy, x-ray diffraction (XRD) and differential scanning calorimeter (DSC). In the Cu60Ti10Zr30 samples annealed at 708 K for times ranging from 0 to 130 min, where the enthalpy...... of the first exothermic peak decreases by 80%, the corresponding XRD patterns still look similar to that for the as-prepared sample. However, the simulated XRD patterns for the pure Cu51Zr14 phase, which is the crystalline phase formed during the first exothermic reaction, with small grain sizes and defects...... clearly show a broadened amorphous-like feature. This might be the reason that no diffraction peaks from the nanocrystalline component were detected in the XRD patterns recorded for the as-cast or as-spun Cu60Ti10+xZr30-x (x=0 and 10) alloys and for the alloys annealed at lower temperatures, in which...

Nanocrystallization in Cu-Zr-Al-Sm Bulk Metallic Glasses

Science.gov (United States)

Sikan, Fatih; Yasar, Bengisu; Kalay, Ilkay

2018-04-01

The effect of rare-earth element (Sm) microalloying on the thermal stability and crystallization kinetics of melt-spun ribbons and suction-cast rods of Zr48Cu38.4Al9.6Sm4 alloy were investigated using differential scanning calorimetry (DSC), X-ray diffraction (XRD), transmission electron microscopy (TEM), and atom probe tomography (APT). The XRD results of constant heating rate annealing indicated that amorphous Zr48Cu38.4Al9.6Sm4 melt-spun ribbons devitrifies into Cu2Sm at 673 K (400 °C). The sequence continues with the precipitation of Cu10Zr7 and then these two phases coexist. XRD and TEM studies on 1 mm diameter as suction-cast rods indicated the precipitation of 30-nm-mean size Cu2Sm crystals during solidification. TEM investigation of the isothermal crystallization sequence of melt-spun ribbons and 1-mm-diameter suction-cast rods revealed the precipitation of Cu2Sm nanocrystals at the onset of crystallization and the restriction of the growth of these nanocrystals up to 10 nm diameter with further annealing. APT analysis of 1-mm-diameter suction-cast rods showed that the limited growth of Cu2Sm nanocrystals is due to sluggish diffusion of Sm and Al-Zr pile up at the interface.

Incorporation of defects into the central atoms model of a metallic glass

International Nuclear Information System (INIS)

Lass, Eric A.; Zhu Aiwu; Shiflet, G.J.; Joseph Poon, S.

2011-01-01

The central atoms model (CAM) of a metallic glass is extended to incorporate thermodynamically stable defects, similar to vacancies in a crystalline solid, within the amorphous structure. A bond deficiency (BD), which is the proposed defect present in all metallic glasses, is introduced into the CAM equations. Like vacancies in a crystalline solid, BDs are thermodynamically stable entities because of the increase in entropy associated with their creation, and there is an equilibrium concentration present in the glassy phase. When applied to Cu-Zr and Ni-Zr binary metallic glasses, the concentration of thermally induced BDs surrounding Zr atoms reaches a relatively constant value at the glass transition temperature, regardless of composition within a given glass system. Using this 'critical' defect concentration, the predicted temperatures at which the glass transition is expected to occur are in good agreement with the experimentally determined glass transition temperatures for both alloy systems.

Thermal expansion of amorphous Zr65Al7.5Cu17.5Ni10 in the vicinity of the glass transition

International Nuclear Information System (INIS)

Geier, N.; Weiss, M.; Moske, M.; Samwer, K.

2000-01-01

The thermal expansion of non-crystalline Zr 65 Al 7.5 Cu 17.5 Ni 10 has been studied in the range of the glass transition and in the undercooled liquid using a dilatometric device. The measuring technique used permits reliable experimental results up to 40 K above the glass transition temperature. The linear thermal expansion coefficient obtained is almost constant in the glassy state with a value of 8.0 x 10 -6 K -1 . It discontinuously increases at the glass transition temperature yielding a value of 20.0 x 10 -6 K -1 in the undercooled liquid. The results are compared with specific heat measurements of the amorphous material in this temperature range and are interpreted in the framework of a cluster model. (orig.)

Investigation on Explosive Welding of Zr53Cu35Al12 Bulk Metallic Glass with Crystalline Copper

Science.gov (United States)

Feng, Jianrui; Chen, Pengwan; Zhou, Qiang

2018-05-01

A Zr53Cu35Al12 bulk metallic glass (BMG) was welded to a crystalline Cu using explosive welding technique. The morphology and the composition of the composite were characterized using optical microscopy, scanning electron microscopy, energy-dispersive x-ray spectroscopy and transmission electron microscopy. The investigation indicated that the BMG and Cu were tightly joined together without visible defects, and a thin diffusion layer appeared at the interface. The captured jet at the end of the welding region mostly comes from the Cu side. Amorphous and partially crystallized structures have been observed within the diffusion layer, but the BMG in close proximity to the interface still retains its amorphous state. Nanoindentation tests reveal that the interface exhibits an increment in hardness compared with the matrix on both sides.

Behavior of high resistance to He{sup 2+} induced irradiation damage in metallic glass

Energy Technology Data Exchange (ETDEWEB)

Wang, Bin [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116024 (China); Mei, Xianxiu, E-mail: xxmei@dlut.edu.cn [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116024 (China); Hou, Wenjing; Wang, Younian [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116024 (China); Wang, Zhiguang [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Dong, Chuang [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, Dalian 116024 (China)

2013-10-01

Highlights: •Metallic glasses and W were irradiated with 500 keV He{sup 2+} at different fluences. •Metallic glasses could maintain amorphous state at different irradiation fluences. •The resistance to He{sup 2+} irradiation of metallic glasses was superior to the one in W metal. •Cu- and Zr-based metallic glasses had better resistance to He{sup 2+} irradiation. -- Abstract: This study details the irradiation of various metallic glasses ((Cu{sub 47}Zr{sub 45}Al{sub 8}){sub 98.5}Y{sub 1.5}, Zr{sub 64}Cu{sub 17.8}Ni{sub 10.7}Al{sub 7.5}, Co{sub 61.2}B{sub 26.2}Si{sub 7.8}Ta{sub 4.8}) and metallic W using He{sup 2+} ions with an energy of 500 keV at irradiation fluences of 2 × 10{sup 17}, 1 × 10{sup 18} and 2 × 10{sup 18} ions/cm{sup 2} to investigate the radiation-resistant properties of these metallic glasses compared to the conventional irradiation-resistant material W. These three metallic glasses were able to maintain an amorphous state during these irradiation fluences. There was no significant irradiation damage at the low irradiation fluence. When the irradiation fluence was increased to 2 × 10{sup 18} ions/cm{sup 2}, a damage layer appeared up to a distance corresponding to the range of the ions away from the surfaces of the Cu- and Zr-based metallic glasses without any visible damage on the surface. Significant surface stripping damage appeared in the Co-based metallic glass. Relatively speaking, surface layer peeling appeared in metallic W along the crystal boundary at a fluence of 1 × 10{sup 18} ions/cm{sup 2}. When the fluence was increased to 2 × 10{sup 18} ions/cm{sup 2}, multilayer peeling, stripping, etc. appeared. The roughness of the Cu- and Zr-based metallic glass showed further smoothing with increasing fluence, while the opposite occurred in the Co-based metallic glass. Within the wavelength range of 400–1700 nm, after irradiation of He{sup 2+} at a fluence of 1 × 10{sup 18} ions/cm{sup 2}, the reflectance of the Cu-based and Co

Excellent plasticity of a new Ti-based metallic glass matrix composite upon dynamic loading

Energy Technology Data Exchange (ETDEWEB)

Wu, R.F. [Laboratory of Applied Physics and Mechanics of Advanced Materials, College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing 100081 (China); Jiao, Z.M. [Institute of Applied Mechanics and Biomedical Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Wang, Y.S.; Wang, Z. [Laboratory of Applied Physics and Mechanics of Advanced Materials, College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Wang, Z.H.; Ma, S.G. [Institute of Applied Mechanics and Biomedical Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Qiao, J.W., E-mail: qiaojunwei@gmail.com [Laboratory of Applied Physics and Mechanics of Advanced Materials, College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing 100081 (China)

2016-11-20

Quasi-static and dynamic compressive properties of in-situ Ti{sub 60}Zr{sub 14}V{sub 12}Cu{sub 4}Be{sub 10} bulk metallic glass matrix composites containing ductile dendrites were investigated. Upon quasi-static compressive loading, the composite exhibits a high fracture strength of ~2,600 MPa, combined with a considerable plasticity of ~40% at room temperature. However, upon dynamic loading, an excellent plasticity of ~16% can be obtained due to the abundant dislocations and severe lattice distortions within dendrites and multiplication of shear bands within the glass matrix analyzed by transmission-electron microscopy. A constitutive relationship is obtained by Johnson-Cook plasticity model, which is employed to model the dynamic flow stress behavior. In addition, under dynamic compression, the adiabatic temperature rise increases with increasing strain rates, resulting in that the softening effect within the glass matrix is obviously enhanced during deformation.

L-shell photoabsorption spectroscopy for solid metals: Ti, V, Cr, Fe, Ni, Cu

International Nuclear Information System (INIS)

Del Grande, N.K.

1989-01-01

Synchrotron radiation measurements of near-threshold and broad-range (400--1500 eV) absolute photoabsorption cross sections were made for five transition metals with ±10% overall uncertainties. Fine structure details of 2p-3d autoionizing resonances are shown with better than 1.0 eV resolution for solid metals: Ti, V, Cr, Fe, Ni, and Cu. Fine structure similar to what we measured can be produced using a multi-configuration Dirac Fock (MCDF) model if a statistical distribution is assumed for the initial atomic states. Calculations were performed in intermediate coupling with configuration interactions by Mau H. Chen. The results are compared with other experimental work and theoretical methodologies. 18 refs., 7 figs

Mechanical Properties of TiTaHfNbZr High-Entropy Alloy Coatings Deposited on NiTi Shape Memory Alloy Substrates

Science.gov (United States)

Motallebzadeh, A.; Yagci, M. B.; Bedir, E.; Aksoy, C. B.; Canadinc, D.

2018-04-01

TiTaHfNbZr high-entropy alloy (HEA) thin films with thicknesses of about 750 and 1500 nm were deposited on NiTi substrates by RF magnetron sputtering using TiTaHfNbZr equimolar targets. The thorough experimental analysis on microstructure and mechanical properties of deposited films revealed that the TiTaHfNbZr films exhibited amorphous and cauliflower-like structure, where grain size and surface roughness increased concomitant with film thickness. More importantly, the current findings demonstrate that the TiTaHfNbZr HEA films with mechanical properties of the same order as those of the NiTi substrate constitute promising biomedical coatings effective in preventing Ni release.

Mechanical Properties of TiTaHfNbZr High-Entropy Alloy Coatings Deposited on NiTi Shape Memory Alloy Substrates

Science.gov (United States)

Motallebzadeh, A.; Yagci, M. B.; Bedir, E.; Aksoy, C. B.; Canadinc, D.

2018-06-01

TiTaHfNbZr high-entropy alloy (HEA) thin films with thicknesses of about 750 and 1500 nm were deposited on NiTi substrates by RF magnetron sputtering using TiTaHfNbZr equimolar targets. The thorough experimental analysis on microstructure and mechanical properties of deposited films revealed that the TiTaHfNbZr films exhibited amorphous and cauliflower-like structure, where grain size and surface roughness increased concomitant with film thickness. More importantly, the current findings demonstrate that the TiTaHfNbZr HEA films with mechanical properties of the same order as those of the NiTi substrate constitute promising biomedical coatings effective in preventing Ni release.

Effect of TiC Additions on the Formation and Microstructural Evolution of Zr66.7Ni33.3Amorphous Alloys%TiC掺杂对Zr66.7Ni33.3非晶形成及结构演化影响的研究

Institute of Scientific and Technical Information of China (English)

耿浩然; 王艳; 王英姿; 夏琳燕

2012-01-01

We used Zr66.7 Ni33.3 binary alloys as base alloys and selected the intermetallic compound TiC as additional particles. The influence of TiC addition on the microstructural evolution induced by mechanical alloying has been investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and differential scanning calorimetry (DSC). The experimental results show that the proper addition of TiC (5wt%) not only shortens the starting time of the amarphization reaction, but also improves the glass forming ability (GFA) of Zr-Ni alloy powders and greatly enhances the mechanical stability of the amorphous composites. Based upon the EDX analysis, we have found that the diffusion of TiC among the atoms of Zr and Ni is inhomogeneous, leading to the increase of the disorder degree of atoms in local regions. Therefore, the TiC addition improves the GFA and stability of the Zr-Ni alloys. The DSC results demonstrate that the effect of the addition of 3 wt% TiC is better than that of the addition of 5 wt% TiC on the improvement of thermal stability of the amorphous phase, suggesting that there is no correlation between thermal stability and mechanical stability of MA induced Zr-Ni-based amorphous alloys.%利用机械合金化法,以Zr66.7Ni33.3合金粉末作为基体,选择TiC作为掺杂物,研究其对机械合金化诱导合金粉末显微结构演化行为的影响.研究发现,掺杂适量的TiC粉末可使Ti和C原子在Zr-Ni间发生不均匀扩散,导致局域范围内原子排列的无序度增大,从而提高非晶形成能力和机械稳定性,其中5wt％ TiC的掺杂效果最佳.此外,3wt％TiC掺杂导致非晶相的热稳定性优于5wt％TiC的掺杂效果,说明机械合金化合成Zr-Ni基非晶合金粉末的机械稳定性和其热稳定性之间无相关性.

Welding of Zr-based bulk metallic glasses

International Nuclear Information System (INIS)

Elahi, M.

2010-01-01

Recently, many bulk metallic glass (BMG) materials with high specific strength, hardness and superior corrosion resistance have been developed and the maximum thickness of some Zr-based BMGs have reached several tenths of millimeters. Nevertheless, homogeneous glassy BMGs are not thick enough to be used for structural applications. In order to extend the engineering applications of BMG materials, BMG welding technologies needed to be developed. Specifically, the welding technologies of dissimilar materials such as BMG materials to crystalline alloys are to be developed. The functional use of the specific properties of each material in dissimilar material combination provides flexible design possibilities for products. In this project electron beam welding is employed to join BMG with BMG of different composition as well as with different crystalline materials (i.e. Hastealoy C-276, Inconel-625 and pure Ti metal). Defects free weld joint was achieved in BMG-BMG welding. Some cracks were produced in melt zone of BMG-Ti and BMG-Hastealoy C-276 welding while at joint they fuse properly with BMG. Inconel-625 could not properly weld with BMG. In all cases, hardness of melt zone was found to be higher than the base metals and the heat affected zone (HAZ). (author)

Structural Origin of the Enhanced Glass-Forming Ability Induced by Microalloying Y in the ZrCuAl Alloy

Directory of Open Access Journals (Sweden)

Gu-Qing Guo

2016-03-01

Full Text Available In this work, the structural origin of the enhanced glass-forming ability induced by microalloying Y in a ZrCuAl multicomponent system is studied by performing synchrotron radiation experiments combined with simulations. It is revealed that the addition of Y leads to the optimization of local structures, including: (1 more Zr-centered and Y-centered icosahedral-like clusters occur in the microstructure; (2 the atomic packing efficiency inside clusters and the regularity of clusters are both enhanced. These structural optimizations help to stabilize the amorphous structure in the ZrCuAlY system, and lead to a high glass-forming ability (GFA. The present work provides an understanding of GFAs in multicomponent alloys and will shed light on the development of more metallic glasses with high GFAs.

AC Calorimetry and Thermophysical Properties of Bulk Glass-Forming Metallic Liquids

Science.gov (United States)

Johnson, William L.

2000-01-01

Thermo-physical properties of two bulk metallic glass forming alloys, Ti34Zr11Cu47Ni8 (VIT 101) and Zr57Nb5Ni12.6Al10CU15.4 (VIT 106), were investigated in the stable and undercooled melt. Our investigation focused on measurements of the specific heat in the stable and undercooled liquid using the method of AC modulation calorimetry. The VIT 106 exhibited a maximum undercooling of 140 K in free radiative cooling. Specific heat measurements could be performed in stable melt down to an undercooling of 80 K. Analysis of the specific heat data indicate an anomaly near the equilibrium liquidus temperature. This anomaly is also observed in y the temperature dependencies of the external relaxation time, the specific volume, and the surface tension; it is tentatively attributed to a phase separation in the liquid state. The VIT 101 specimen exhibited a small undercooling of about 50 K. Specific heat measurements were performed in the stable and undercooled melt. These various results will be combined with ground based work such as the measurement of T-T-T curves in the electrostatic levitator and low temperature viscosity and specific heat measurements for modeling the nucleation kinetics of these alloys.

Glass forming in La2O3-TiO2-ZrO2 ternary system by containerless processing

Science.gov (United States)

Kaneko, Masashi; Kentei Yu, Yu; Kumar, Vijaya; Masuno, Atsunobu; Inoue, Hiroyuki; Odawara, Osamu; Yoda, Shinichi

The containerless processing is an appropriate method to create new glasses, because it sup-presses nucleation at the boundary between liquid and crucible during solidification and it enables molten samples to be solidified without crystallization. Recently, we have succeeded in forming BaTi2 O5 glass in the bulk state by using an aerodynamic levitation furnace. BaTi2 O5 glass includes no traditional glass network former and it possesses high electric permittivity [1, 2]. From the point of view of optical application, BaTi2 O5 glass has high refractive indices over 2.1. BaTi2 O5 glass, however, vitrify only in a small sphere, and it crystallize when its diameter exceed 1.5 mm. In order to synthesize new titanate oxide glasses which possess higher refractive indices and larger diameter than BaTi2 O5 , La and Zr can be used as substitutive components. When Ba is replaced with La, refractive indices are expected to increase because of the heavier element. The addition of a third element is thought to be effective for enhance-ment of glass formation ability and Zr can be a candidate because Ti and Zr are homologous. In this research, we have succeeded in forming new bulk glass in La2 O3 -TiO2 -ZrO2 ternary system by means of the aerodynamic levitation furnace. We investigated the glass forming region, thermal properties and optical properties of La2 O3 -TiO2 -ZrO2 glass. Glass transition temperature, crystallization temperature, density, refractive indices and transmittance spectra were varied depending on the chemical composition. Reference [1] J. Yu et al, "Fabrication of BaTi2O5 Glass-Ceramics with Unusual Dielectric Properties during Crystallization", Chem-istry of Materials, 18 (2006) 2169-2173. [2] J. Yu et al., "Comprehensive Structural Study of Glassy and Metastable Crystalline BaTi2O5", Chemistry of Materials, 21 (2009) 259-263.

Effects of configurational changes on electrical resistivity during glass-liquid transition of two bulk metal-alloy glasses

Energy Technology Data Exchange (ETDEWEB)

Aji, D. P. B.; Johari, G. P., E-mail: joharig@mcmaster.ca [Department of Materials Science and Engineering, McMaster University, Hamilton, Ontario L8S 4L7 (Canada)

2014-12-14

Consequences of increase in structural fluctuations on heating Pd{sub 40}Ni{sub 10}Cu{sub 30}P{sub 20} and Zr{sub 46.75}Ti{sub 8.25}Cu{sub 7.5}Ni{sub 10}Be{sub 27.5} through their glass to liquid transition range were investigated by measuring the electrical resistivity, ρ, an electron scattering property. The temperature coefficient of resistivity (TCR = (1/ρ) dρ/dT) of the liquid and glassy states is negative. The plots of their ρ against T in the T{sub g} (glass to liquid transition) range show a gradual change in the slope similar to the change observed generally for the plots of the density, elastic modulus, and refractive index. As fluctuations in the melt structure involve fewer configurations on cooling, ρ increases. In the energy landscape description, the melt's structure explores fewer minima with decrease in T, vibrational frequencies increase, and electron scattering and ρ increase. Plots of (−dρ/dT) against T resemble the plot of the specific heat of other glasses and show a sub-T{sub g} feature and a rapid rise at T near T{sub g}. Analysis shows that the magnitude of negative TCR is dominated by change in the phonon characteristics, and configurational fluctuations make it more negative. The TCR of the liquid and glassy states seems qualitatively consistent with the variation in the structure factor in Ziman's model for pure liquid metals as extended by Nagel to metal alloys and used to explain the negative TCR of a two-component metal glass.

Application of amorphous filler metals in production of fusion reactor high heat flux components

Energy Technology Data Exchange (ETDEWEB)

Kalin, B A [Moskovskij Inzhenerno-Fizicheskij Inst., Moscow (Russian Federation); Fedotov, V T [Moskovskij Inzhenerno-Fizicheskij Inst., Moscow (Russian Federation); Grigoriev, A E [Moskovskij Inzhenerno-Fizicheskij Inst., Moscow (Russian Federation); Sevriukov, O N [Moskovskij Inzhenerno-Fizicheskij Inst., Moscow (Russian Federation); Pliushev, A N [Moskovskij Inzhenerno-Fizicheskij Inst., Moscow (Russian Federation); Skuratov, L A [Moskovskij Inzhenerno-Fizicheskij Inst., Moscow (Russian Federation); Polsky, V I [Moskovskij Inzhenerno-Fizicheskij Inst., Moscow (Russian Federation); Yakushin, V L [Moskovskij Inzhenerno-Fizicheskij Inst., Moscow (Russian Federation); Virgiliev, Yu S [State Research Institute of Graphite, Electrodnaya St. 2, 115524 Moscow (Russian Federation); Vasiliev, V L [TRINITI, Troitsk, 142092 Moscow District (Russian Federation); Tserevitinov, S S [TRINITI, Troitsk, 142092 Moscow District (Russian Federation)

1995-03-01

Amorphous ribbon-type filler metals represent a promising facility for fastening heterogeneous materials together. The advantage results from the homogeneity of element and phase compositions and the strictly specified geometrical dimensions of such fillers. Amorphous fillers Zr-Ti-Fe-Be, Zr-Ti-Ni-Cu and Ti-Zr-Ni-Cu and microcrystalline fillers Al-Si and Cu-Sn-Mn-In-Ni were produced by quenching at a rate of about 10{sup 6}Ks{sup -1}. Brazing of graphite with metals (Cu+MPG-6, Cu+RGT, Mo+MIG-1, V+MIG-1, V+RGT) was accomplished using ribbon-type fillers. Two types of metal-based samples were produced in the form of plates and rakes. The rakes were made by brazing three small graphite bars to the metal, the 2mm space between the bars being 0.25 of the bar height. The results of metallographic studies of the brazing zone and of tests on brazed structures treated by pulsed energy fluxes are discussed. (orig.).

Short-to-Medium-Range Order and Atomic Packing in Zr48Cu36Ag8Al8 Bulk Metallic Glass

Directory of Open Access Journals (Sweden)

Yong Xu

2016-10-01

Full Text Available Due to its excellent glass-forming ability (GFA, the Zr48Cu36Al8Ag8 bulk metallic glass (BMG is of great importance in glass transition investigations and new materials development. However, due to the lack of detailed structural information, the local structure and atomic packing of this alloy is still unknown. In this work, synchrotron measurement and reverse Monte Carlo simulation are performed on the atomic configuration of a Zr-based bulk metallic glass. The local structure is characterized in terms of bond pairs and Voronoi tessellation. It is found that there are mainly two types of bond pairs in the configuration, as the body-centered cubic (bcc-type and icosahedral (ico-type bond pairs. On the other hand, the main polyhedra in the configuration are icosahedra and the bcc structure. That is, the bcc-type bond pairs, together with the ico-type bond pairs, form the bcc polyhedra, introducing the distortion in bcc clusters in short range. However, in the medium range, the atoms formed linear or planar structures, other than the tridimensional clusters. That is, the medium-range order in glass is of 1D or 2D structure, suggesting the imperfect ordered packing feature.

Structural stability of Pd40Cu30Ni10P20 metallic glass in supercooled liquid region

International Nuclear Information System (INIS)

Jiang, J.Z.; Saksl, K.

2004-01-01

Phase separation of bulk and ribbon Pd 40 Cu 30 Ni 10 P 20 glasses, annealed in the supercooled liquid region at ambient pressure and high pressures, has been studied by means of differential scanning calorimetry (DSC) and X-ray diffraction techniques. DSC measurements show only one glass transition event in all annealed samples, indicating that no phase separation occurs in the alloy annealed in the supercooled liquid region. Phase analyses reveal at least six crystalline phases in the crystallized sample: monoclinic, tetragonal Cu 3 Pd-like, rhombohedral, fcc-Ni 2 Pd 2 P, fcc-(Ni, Pd) solid solution, and body-centered tetragonal (bct) Ni 3 P-like phases. Annealing treatments under external pressures in the vicinity of the glass transition temperature neither induce phase separation nor alter the glass transition temperature of the Pd 40 Cu 30 Ni 10 P 20 bulk glass

Evidence of icosahedral short-range order in Zr70Cu30 and Zr70Cu29Pd1 metallic glasses

DEFF Research Database (Denmark)

Saksl, K.; Franz, H.; Jovari, P.

2003-01-01

Change in local atomic environment during crystallization of Zr-based glassy alloys was studied by extended x-ray absorption fine structure (EXAFS) spectroscopy. The formation of icosahedral quasicrystalline phase followed by crystallization of tetragonal CuZr2 has been observed in the Zr70Cu29Pd1...... glassy alloy during annealing up to 850 K. On the other hand, the binary Zr70Cu30 alloy shows a single glassy to crystalline CuZr2 phase transformation. The local atomic environment of as-quenched Zr70Cu30 alloy is matched to an icosahedral local atomic configuration, which is similar to that of the as......-quenched Zr70Cu29Pd1 alloy and the alloy annealed at 593 K containing icosahedral phase. Considering that the supercooled liquid region appears prior to crystallization in the Zr70Cu30 glassy alloy, the observed results support the theory claiming a strong correlation between the existence of local...

Tuning apparent friction coefficient by controlled patterning bulk metallic glasses surfaces

Science.gov (United States)

Li, Ning; Xu, Erjiang; Liu, Ze; Wang, Xinyun; Liu, Lin

2016-12-01

Micro-honeycomb structures with various pitches between adjacent cells were hot-embossed on Zr35Ti30Cu8.25Be26.75 bulk metallic glass surface. The effect of pitch geometry on the frictional behavior of metallic glass surface was systematically investigated. The results revealed that all textured metallic glass surfaces show a reduction in friction coefficient compared to smooth surface. More intriguingly, the friction coefficient first decreased and then increased gradually with increasing pitches. Such unique behavior can be understood fundamentally from the perspective of competing effects between contact area and local stress level with increasing pitches. This finding not only enhance the in-depth understanding of the mechanism of the significant role of surface topography on the frictional behavior of metallic glass surface, but also opens a new route towards other functional applications for bulk metallic glasses.

Damping characteristics of a Ti40.5Ni49.5Zr10 shape memory alloy

International Nuclear Information System (INIS)

Hsieh, S.F.; Wu, S.K.

2005-01-01

Ti 40.5 Ni 49.5 Zr 10 alloy undergoes B2-bar B19' martensitic transformation. Damping capacities of B19' and B2 phases of this alloy are lower than those of Ti 51 Ni 49 alloy due to Zr atoms solid-soluted hardening. Transformation temperatures of this alloy decrease, but transformation peak heights Q max -1 increase with increasing aging time at 300 o C due to the formation of finer (001) M twins for specimens aged longer. The Q max -1 peaks of the slightly cold-rolled Ti 40.5 Ni 49.5 Zr 10 alloy are higher than those of the as-annealed alloy, which may be because the thinner twins are induced by small deformation

Structure of as cast L12 compounds in Al3Zr-base alloys containing Cu and Mn

International Nuclear Information System (INIS)

Virk, I.S.; Varin, R.A.

1991-01-01

It was first shown that the low symmetry, tetragonal DO 23 crystal structure of Al 3 Zr intermetallic can be changed to the related cubic L1 2 crystal structure by alloying with Ni (Al 5 NiZr 2 ) and Cu(Al 5 CuZr 2 ). It has been reported that previous work has successfully modified Al 3 Zr with Fe, Cu, Cr and Ni obtaining nearly single phase materials with L1 2 structure. However, they only studied the microstructure and mechanical properties of Fe - modified intermetallic (Al-6at% Fe-25at% Zr). The purpose of the paper is to describe and interpret experimental observations on the microstructure of Al 5 CuZr 2 and Al 66 Mn 9 Zr 25 (at.%) modifications of base Al 3 Zr intermetallic. The one modified with Mn has not been reported in literature although its Al 3 Ti - base counterpart has recently been successfully produced (3, 4)