Cu46Zr46A14.8Ti3.2 bulk metallic glass （BMG） was successfully synthesized by copper-mold casting and the mechanical properties at room temperature were measured by compression tests. The structure and thermal charac...Cu46Zr46A14.8Ti3.2 bulk metallic glass （BMG） was successfully synthesized by copper-mold casting and the mechanical properties at room temperature were measured by compression tests. The structure and thermal characteristics were analyzed by XRD and DSC, and the fracture surface morphology was examined by SEM. The glassy alloy with 4 mm in diameter shows an high fracture strength of 1 960 MPa, with an improvement of about 20% compared to the ultimate compression fracture strength of the Cu46Zr46A18 BMG, which suggests that the Ti addition improves the compression fracture strength. The different degrees of the adiabatic heating induce four types of fracture features： a vein-like structure, an elongated and striated vein pattern, melting and smooth regions. The elongated and striated vein patterns as well as the melting region show that enormous strain energy is released, which causes significant adiabatic heating. Furthernaore, many micro-cracks observed in the smooth region are caused by the strong shear force. In addition, the strong shear force leads to many shear bands as well as the melting in the lateral surface.展开更多
Surfaces of three types of CuZr-based bulk metallic glasses （BMGs） were modified by laser surface treatment （LST）, and the influence of the treatment on structure and mechanical properties of these alloys was inve...Surfaces of three types of CuZr-based bulk metallic glasses （BMGs） were modified by laser surface treatment （LST）, and the influence of the treatment on structure and mechanical properties of these alloys was investigated. The phase structure of as-cast and laser-treated samples was characterized by XRD and the morphology of the alloys after fracture was examined by SEM. The compressive plasticity of treated Cu47.sZr47.sAI5 and Cu46.sZr47.sAlsCo~ BMGs can be improved from 0.5% to 2.0% and from 1.2% to 5.7% respectively compared with the as-cast ones, while （Cu0.55Zr0.40Ala05）99Er~ BMG shows insignificant change of plasticity. The improvement in plasticity is attributed to induced crystallization of B2 CuZr phase in the treated sur- face zone of selected metallic glasses.展开更多
基金Project(NCET-10-0360) supported by the Program for New Century Excellent Talents in University,ChinaProject supported by the Fundamental Research Funds for the Central Universities,China
文摘Cu46Zr46A14.8Ti3.2 bulk metallic glass （BMG） was successfully synthesized by copper-mold casting and the mechanical properties at room temperature were measured by compression tests. The structure and thermal characteristics were analyzed by XRD and DSC, and the fracture surface morphology was examined by SEM. The glassy alloy with 4 mm in diameter shows an high fracture strength of 1 960 MPa, with an improvement of about 20% compared to the ultimate compression fracture strength of the Cu46Zr46A18 BMG, which suggests that the Ti addition improves the compression fracture strength. The different degrees of the adiabatic heating induce four types of fracture features： a vein-like structure, an elongated and striated vein pattern, melting and smooth regions. The elongated and striated vein patterns as well as the melting region show that enormous strain energy is released, which causes significant adiabatic heating. Furthernaore, many micro-cracks observed in the smooth region are caused by the strong shear force. In addition, the strong shear force leads to many shear bands as well as the melting in the lateral surface.
基金supported by the National Natural Science Foundation of China (Grant Nos.51071008 and 51131002)the Program for New Century Excellent Talents in the University
文摘Surfaces of three types of CuZr-based bulk metallic glasses （BMGs） were modified by laser surface treatment （LST）, and the influence of the treatment on structure and mechanical properties of these alloys was investigated. The phase structure of as-cast and laser-treated samples was characterized by XRD and the morphology of the alloys after fracture was examined by SEM. The compressive plasticity of treated Cu47.sZr47.sAI5 and Cu46.sZr47.sAlsCo~ BMGs can be improved from 0.5% to 2.0% and from 1.2% to 5.7% respectively compared with the as-cast ones, while （Cu0.55Zr0.40Ala05）99Er~ BMG shows insignificant change of plasticity. The improvement in plasticity is attributed to induced crystallization of B2 CuZr phase in the treated sur- face zone of selected metallic glasses.
