International Journal of Minerals, Metallurgy and Materials

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Cluster-based composition rules for ternary alloy systems

Chuang Dong, Qing Wang, Weirong Chen, Qingyu Zhang, Jianbing Qiang, Yingmin Wang

2007, 14(S1): 1-3. doi: 10.1016/S1005-8850(07)60096-6

中文摘要(264) PDF(17) SpringerLink

摘要:
The cluster-based composition rule in ternary alloy systems including quasicrystals, bulk metallic glasses, crystalline phases and Lave phases-related body-centered cubic (BCC) solid solution forming systems was summarized. The so-called cluster line in a ternary phase diagram refers to a straight composition line linking a specific binary cluster to the third element. The composition ranges of quasicrystals and bulk metallic glasses can be determined by the direct use of cluster lines, where two cluster lines intersect at the optimum phase forming composition. Furthermore, the alloys on the cluster line in Laves phase-related BCC solid solution alloy systems have larger hydrogen storage capacities.

Materials

Influence of flux treatment on the glass forming ability of Pd-Si binary alloys

Na Chen, Kefu Yao, Fang Ruan

2007, 14(S1): 4-7. doi: 10.1016/S1005-8850(07)60097-8

中文摘要(218) PDF(10) SpringerLink

摘要:
Pd₈₁Si₁₉ amorphous alloys were prepared by combination methods of melt spinning and B₂O₃ flux treatment. A comparison between the ribbons prepared from the fluxed ingots and the non-fluxed ones has been carried out. The result reveals that after fluxing treatment the glass transition temperature of the as-prepared glassy ribbons is reduced while the initial crystallization temperature is enhanced. It results in that the supercooled liquid region (defined as the difference between the initial crystallization temperature and the glass transition temperature) of the glassy alloy treated with fluxing technology has been increased from 31 to 42 K. This shows that fluxing technique can enhance the glass forming ability (GFA) of the binary alloy and improve the thermal stability of supercooled liquid of the glassy alloy.

Materials

Critical serrated flow features during nanoindentation in La-based bulk metallic glasses

Wei Peng, Taihua Zhang, Yuan Liu, Lei Li, Bingchen Wei

2007, 14(S1): 8-12. doi: 10.1016/S1005-8850(07)60098-X

中文摘要(227) PDF(8) SpringerLink

摘要:
La_57.6Al_17.5(Cu,Ni)_24.9 and La₆₄Al₁₄(Cu,Ni)₂₂ bulk metallic glasses (BMGs) were prepared by copper-mould casting method. Plastic deformation behavior of the two BMGs at various loading rates was studied by nanoindentation. The results showed that the La_57.6Al_17.5(Cu,Ni)_24.9 BMG with a glass transition temperature of 423 K exhibited prominent serrated flow at low loading rates, whereas less pronounced serrated flow at high rates during nanoindentation. In contrast, the La₆₄Al₁₄(Cu,Ni)₂₂ BMG with a glass transition temperature of 401 K exhibited prominent serrated flow at high loading rates. The different rate dependency of serrated flow in the two La-based BMGs is related to the different glass transition temperature, and consequently the degree of viscous flow during indentation at room temperature. A smoother flow occurs in the alloy with relatively lower glass transition temperature, due to the relaxation of stress concentration.

Materials

Glass forming ability, microstructure and magnetic property of NdAlNiCuFe alloys

Zhi Zhang, Zhaolong Wang, Dongman Yu, Chunling Chen

2007, 14(S1): 13-18. doi: 10.1016/S1005-8850(07)60099-1

中文摘要(178) PDF(6) SpringerLink

摘要:
The glass forming ability (GFA), microstructure and magnetic property in (Nd₆₀Al₁₀Ni₁₀)Cu_20-xFe_x (0≤x≤ 20) alloys were investigated by using X-ray diffraction (XRD), differential scanning calorimetry (DSC), high resolution transmission electron microscopy (HRTEM) and magnetic property measurement. It is shown that the GFA of the alloys decreases with Fe content. The samples for bulk cylinders with x≤10 show a distinct endothermic peak in the DSC traces due to a glass transition in the range of 421-438 K. With further increasing Fe, the glass transition is masked by the crystallization. The microstructure of the Nd-based alloy can change progressively from full glassy state into composite state with nanocrystalline particles in the glassy matrix indicating the glass forming ability degrades with increasing Fe. The average size of nanocrystals increases with Fe and the distribution changes from homogenous to heterogeneous. The magnetic property varies from paramagnetic to hard magnetic when the Fe content increases up to about 4at% indicating that the magnetic property is related to the metastable phases.

Materials

Bulk glass formation in ternary Cu-Zr-Ti system

Hua Men, Junying Fu, Chaoli Ma, Shujie Pang, Tao Zhang

2007, 14(S1): 19-22. doi: 10.1016/S1005-8850(07)60100-5

中文摘要(249) PDF(8) SpringerLink

摘要:
The formation of bulk metallic glasses (BMGs) in ternary Cu-Zr-Ti system was investigated by a copper mold casting method. The nature of the amorphous phase was verified by X-ray diffraction (XRD) and differential scanning calorimetry (DSC). It was demonstrated that the BMGs could be formed in a broad composition range in this system. Cu₅₀Zr_42.5Ti_7.5, Cu₆₀Zr_27.5Ti_12.5, Cu₆₀Zr₃₀Ti₁₀ and Cu₆₀Zr_32.5Ti_7.5 alloys exhibit strong glass-forming ability (GFA), and fully glassy rods of 5 mm in diameter can be obtained. In the center region of the ternary diagram, however, the GFA of the alloys was degraded due to the presence of Laves phase. The degradation of the GFA results from easy nucleation of the Laves phase in the undercooled liquid.

Materials

Thermal stability and glass-forming ability of Y-Ce-Co-Al bulk metallic glasses

Jun Li, Xueshan Xiao, Yuanda Dong

2007, 14(S1): 23-25. doi: 10.1016/S1005-8850(07)60101-7

中文摘要(219) PDF(8) SpringerLink

摘要:
The thermal stability and glass-forming ability of Y_56-xCe_xCo₂₀Al₂₄ (x=15, 20, 25, 28, 38, 41, 44) bulk metallic glasses with a diameter of 5 mm were investigated by differential scanning calorimetry and X-ray diffraction. The results show that the thermal stability of the alloys decreases with the addition of Ce. It has the best glass-forming ability when x=25, whose calculated values can reach about 30 mm in diameter. The effect of Ce element could be explained on the view of Miedema’s theory and electronegativity difference of amorphous alloys.

Materials

A cluster line approach to finding new Fe-B-Y-Nb-Zr bulk metallic glasses

Nigel Pemberton-Pigott, Qing Wang, Weirong Chen, Qingyu Zhang, Jiang Wu, Yanhui Li, Jianbing Qiang, Chuang Dong

2007, 14(S1): 26-30. doi: 10.1016/S1005-8850(07)60102-9

中文摘要(341) PDF(6) SpringerLink

摘要:
The glass forming ability of the [(Fe_12/13Y_1/13)_100-xB_x]₉₆Nb₂Zr₂ (x=9–26) system was investigated using a series of cluster lines. Three types of clusters, an icosahedron (Fe₁₂Y), a capped Archimedes anti-prism (Fe₈B₃) and a capped trigonal prism (Fe₉B), as well as a binary eutectic (Fe₈₃B₁₇) were considered. Bulk glassy alloy rods of 3 mm in diameter were synthesized using a copper mold suction-casting method. The glass transition temperature was observed for all samples in the boron range of 15.9at%-25.7at%, with the alloy at 15.9at% of boron having the best thermal properties. The ferrous-based bulk metallic glasses (BMG) obtained have high reduced glass transition temperatures with the maximum reaching 0.63 and large supercooled liquid regions with the maximum reaching 111 K. Magnetic testing revealed a large value of coercive force and remanent magnetization, being 11 kA/m and 0.1 T, respectively.

Materials

Effects of Ta addition on the microstructure and mechanical properties of Ti₄₀Zr₂₅Ni₈Cu₉Be₁₈ amorphous alloy

Jinna Mei, Jinshan Li, Hongchao Kou, Rui Hu, Hengzhi Fu, Lian Zhou

2007, 14(S1): 31-35. doi: 10.1016/S1005-8850(07)60103-0

中文摘要(259) PDF(7) SpringerLink

摘要:
The effects of Ta addition on the microstructure and mechanical properties of Ti₄₀Zr₂₅Ni₈Cu₉Be₁₈ bulk amorphous alloy were investigated by using X-ray diffraction (XRD), transmission electron microscopy (TEM), scan electron microscopy (SEM) and compressive testing. As a result, the addition of Ta (0-8at%) prompted the successive precipitation of quasicrystalline phase, CuTi₂ phase and bcc β-Ti solid solution. Additionally, the addition of less Ta content (3at%-5at%) led to the formation of amorphous matrix/nanoquasicrystal/CuTi₂ complex phase structure; and nanoquasicrystals, as reinforcement precipitates, improved the fracture strength of Ti-Zr-Ni-Cu-Be-Ta alloys, which led to the high compressive fracture strength 1856 MPa of Ta₅ alloy. With increasing Ta content (5at%-8at%), although the ductile dendritic β-Ti solid solution was precipitated, the strength and plasticity decreased to a great extent resulting from the growth of quasicrystalline phase and CuTi₂ phase.

Materials

Formation and thermal stability of Cu-Zr-Al-Er bulk metallic glasses with high glass-forming ability

Junying Fu, Hua Men, Shujie Pang, Chaoli Ma, Tao Zhang

2007, 14(S1): 36-38. doi: 10.1016/S1005-8850(07)60104-2

中文摘要(259) PDF(8) SpringerLink

摘要:
The formation and thermal stabilities of Cu_46.25Zr_46.25-xAl_7.5Er_x (x=0 to 8) bulk metallic glasses (BMGs) were investigated. The addition of a small amount of Er (2at%) for replacing Zr effectively improves the glass-forming ability of Cu_46.25Zr_46.25Al_7.5 alloy, and the glassy rod with a diameter of at least 12 mm can be formed. The glass transition temperature (T_g), temperature interval of supercooled liquid region △T_x (=T_x-T_g), and reduced glass transition temperature T_rg (=T_g/T_l) of Cu_46.25Zr_44.25Al_7.5Er₂ glassy alloy are 699 K, 62 K and 0.607, respectively.

Materials

Bulk metallic glasses formed by alloying the Cu₆Zr₅ cluster

Yanhui Li, Qing Wang, Jiang Wu, Jianbing Qiang, Chuang Dong

2007, 14(S1): 39-42. doi: 10.1016/S1005-8850(07)60105-4

中文摘要(253) PDF(6) SpringerLink

摘要:
The bulk metallic glass formation in the Cu-Zr-M ternary systems by alloying of a binary basic Cu₆Zr₅ cluster was investigated, where M stands for Sn, Mo, Ta, Nb, Ag, Al and Ti. The Cu₆Zr₅ cluster is a capped Archimedean antiprism that characterizes the local structure of the Cu₁₀Zr₇ crystalline phase. This cluster composition almost superposes with Cu-Zr eutectic Cu_0.56Zr_0.44. A series of alloys along the cluster line (Cu₆Zr₅)_1-xM_x were examined for their glass forming abilities. Alloy rods with a diameter of 3 mm were prepared by copper mould suction casting method and analyzed by XRD and thermal analysis. The Cu-Zr based bulk metallic glasses were discovered with minor Nb, Sn, Mo, Ta additions (≤2at%) and Al, Ti, Ag (8at%≤concentration≤9at%). The alloying mechanism was discussed in the light of atomic size, cluster-linking structure and electron concentration factors.

Materials

Mg-Cu-Zn-Y-Zr bulk metallic glassy composite with high strength and plasticity

Wei Tian, Shujie Pang, Hua Men, Chaoli Ma, Tao Zhang

2007, 14(S1): 43-45. doi: 10.1016/S1005-8850(07)60106-6

中文摘要(235) PDF(7) SpringerLink

摘要:
Mg₆₅Cu₂₀Zn₅Y₉Zr₁ bulk metallic glass matrix composite with a diameter of 2 mm was produced by copper mold casting. Upon cooling the Mg₆₅Cu₂₀Zn₅Y₉Zr₁ melt, Mg₂Cu acicular crystalline phase precipitates uniformly with a size of about 20 μm long and 1 μm thick while the remaining melt undergoes glass transition. Room temperature compression tests revealed that the high fracture strength up to 830 MPa and the plastic strain of 2.4% before failure are obtained for the Mg-based bulk metallic glass matrix composite. The formation of the Mg₂Cu phase was proposed to contribute to high strength and plastic deformation of the material.

Materials

Formation and mechanical properties of ductile Fe-based amorphous alloys using a cast iron with minor addition of B and Al

Kun Tian, Shujie Pang, Hua Men, Tao Zhang

2007, 14(S1): 46-49. doi: 10.1016/S1005-8850(07)60107-8

中文摘要(267) PDF(7) SpringerLink

摘要:
Fe-based amorphous alloys with ductility were synthesized using the commercial cast iron QT50 (denoted as QT) with the combining minor addition of B and Al by single roller melt-spinning. The melt-spun (QT_1-xB_x)₉₉Al₁ (x is from 0.006wt% to 0.01wt%) amorphous alloys exhibit onset crystallization temperatures and Curie temperatures of 759-780 and 629-642 K respectively, and which increase with B content. The amorphous ribbons are ductile and can be bent 180° without breaking. With the increase in B content from 0.006wt% to 0.01wt%, the Vickers microhardness of the amorphous alloys increases from Hv 830 to Hv 1110. The effects of the additional B and Al elements on the glass forming ability and mechanical properties were also discussed.

Materials

Glass formation of ternary Sm-based Sm-Al-Co bulk metallic glasses

Jiang Wu, Qing Wang, Weirong Chen, Qingyu Zhang, Jianbing Qiang, Chuang Dong

2007, 14(S1): 50-53. doi: 10.1016/S1005-8850(07)60108-X

中文摘要(257) PDF(7) SpringerLink

摘要:
Ternary Sm-based Sm-Al-Co alloys at specific compositions designed using an e/a- and cluster-related criteria exhibit high glass forming abilities and form bulk glassy rods of 3 mm in diameter by a copper mold suction-casting method. Four compositions of bulk metallic glasses (BMGs) are Sm₅₀Al₂₅Co₂₅, Sm₅₂Al₂₄Co₂₄, Sm₅₄Al₂₃Co₂₃ and Sm₅₆Al₂₂Co₂₂, which all satisfy a constant conduction electron concentration of 1.5. Among them, the BMG exhibiting the largest reduced glass transition temperature (T_rg) is Sm₅₀Al₂₅Co₂₅, which reaches 0.648. The glass transition temperature T_g and the onset crystallization temperature T_x of this alloy are respectively 579 and 640 K at a heating rate of 20 K/min.

Materials

Application of an analytical phase transformation model

Feng Liu, Changlin Yang, Wei Yang, Gencang Yang, Yaohe Zhou

2007, 14(S1): 54-58. doi: 10.1016/S1005-8850(07)60109-1

中文摘要(243) PDF(7) SpringerLink

摘要:
An analytical phase transformation model has been used to study the kinetics of crystallization of amorphous alloys subjected to either isothermal or isochronal anneals. The model has been applied to Mg_82.3Cu_17.7 and Pd₄₀Cu₃₀P₂₀Ni₁₀, employing isothermal and isochronal differential scanning calorimetry. Applying different combinations of nucleation and growth mechanisms to the same experiments, the nucleation and growth modes dominating the crystallization and the values for the corresponding kinetic parameters, including the constant activation energies for nucleation and growth, have been determined. Further, the influence of isothermal pre-annealing on subsequent isochronal crystallization kinetics, involving a gradual change of nucleation mode up to site saturation with increase of pre-annealing, can be analyzed.

Materials

Porous bulk metallic glass fabricated by powder hot pressing

Keqiang Qiu, Bo Yu, Yinglei Ren

2007, 14(S1): 59-63. doi: 10.1016/S1005-8850(07)60110-8

中文摘要(178) PDF(7) SpringerLink

摘要:
A synthesis method for the production of porous bulk metallic glass (BMG) was introduced. This method utilizes the superplastic forming ability of amorphous powder in the supercooled liquid (SCL) state and intenerating salt mixture as a placeholder to produce BMG foam by using a hot die pressing method. Scanning electron microscope (SEM), X-ray diffraction (XRD) and differential scanning calorimetry (DSC) were employed to characterize the morphologies of foaming structure, the crystallization and the percentage of crystallization of the as-produced porous BMG. The results suggested that the formation of porous structure by superplastic forming process is feasible. Good bonding effect was observed between amorphous powder particles. Less than 6.5% of crystalline phases were formed during hot pressing, and less than 5.5% of residual salt was enclosed in the foam. To remove any residual salt particles, salt preforms with three-dimensional network and good connectivity is necessary.

Materials

A study of the crystallization kinetics of Ge-Te amorphous systems

Feng Yan, Tiejun Zhu, Xinbing Zhao, Shurong Dong

2007, 14(S1): 64-67. doi: 10.1016/S1005-8850(07)60111-X

中文摘要(214) PDF(7) SpringerLink

摘要:
The glass-forming ability of binary Ge_xTe_100-x (x=15, 20, 30) alloys was investigated. The crystallization mechanism of these amorphous bulks was studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). The temperature of glass transition, the temperature of crystallization, the activation energy for glass transition and crystallization, and the order of the crystallization mechanism were calculated from the different heating-rates.

Materials

Plastic deformation behavior of Fe₄₀Ni₄₀P₁₄B₆ bulk metallic glass investigated by nanoindentation

Changqing Zhang, Kefu Yao

2007, 14(S1): 68-72. doi: 10.1016/S1005-8850(07)60112-1

中文摘要(219) PDF(6) SpringerLink

摘要:
Fe₄₀Ni₄₀P₁₄B₆ bulk metallic glass rods have been prepared by water quenching the fluxed alloy. The deformation behavior was investigated by nanoindentation tests and compressing tests. The average hardness and elastic modulus of the as-prepared Fe₄₀Ni₄₀P₁₄B₆ BMG (bulk metallic glass) measured by nanoindentation tests are 8.347 and 176.61 GPa respectively. The displacement-load curve shows “pop-in” characteristics which correspond to the loading rate bursts. Many shear bands around the indent were observed. The as-prepared Fe-based BMG exhibits a compressive plastic strain of 5.21%, which is much larger than that of other Fe-based glassy alloys and most of other BMGs.

Materials

Crystallization of amorphous Ni-Zr alloys during heating with molecular dynamics simulations

Quanwen Yang, Shujie Pang, Tao Zhang

2007, 14(S1): 73-76. doi: 10.1016/S1005-8850(07)60113-3

中文摘要(275) PDF(9) SpringerLink

摘要:
The heating processes of amorphous Ni_xZr_100-x(x=10, 16.7, 33.3) alloys were investigated with molecular dynamics simulations. The simulation results show that the crystallization of amorphous alloys during heating is controlled by the heating rate and the alloy’s composition. The slower heating rate depresses the crystallizing temperatures and the melting temperatures of the amorphous alloys. Crystallization can be eliminated at rapid heating rates, the critical value of which decreases with increasing Ni content of the studied amorphous Ni-Zr alloys. Different crystalline structures formed during crystallizing depend on the heating rate, and the transition between crystalline structures was observed in the heating processes.

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2007年第14卷第S1期