Work toughening effect in Zr_(41)Ti_(14)Cu_(12.5)Ni_(10)Be_(22.5) bulk metallic glass  

作　　者：QIU ShengBao GONG Pan YAO KeFu 

机构地区：[1]Key Laboratory for Advanced Materials Processing Technology, Department of Mechanical Engineering, Tsinghua University,Beijing 100084, China

出　　处：《Chinese Science Bulletin》2011年第36期3942-3947,共6页

基　　金：supported by the National Basic Research Program of China (2007CB613905);the National Natural Science Foundation of China (50671050 and 50971073);the National Center for Nanoscience and Technology of China

摘　　要：Work hardening is a well-known phenomenon occurring in crystalline metals during deformation,which has been widely used to increase the strength of metals although their ductility is usually reduced simultaneously. Here we report that the plastic strain of Zr41Ti14Cu12.5Ni10Be22.5 (at.%) bulk metallic glasses has been increased from 0.3% for the as-cast sample to 2.5%-8.0% for samples that have experienced pre-deformation under constrained conditions. The pre-deformed glassy alloys possess more free volume and abundant introduced shear bands,which are believed to promote the activation of shear bands in post-deformation and result in an increase in plasticity. The orientation of the pre-introduced shear bands relative to the loading direction will affect the deformation behavior of pre-deformed samples. The present results show that pre-deformation of this glassy alloy will result in work toughening. This work toughening effect can be removed by isothermal annealing at a sub-Tg (glass transition) temperature,which causes annihilation of free volume and healing of shear bands.Work hardening is a well-known phenomenon occurring in crystalline metals during deformation,which has been widely used to increase the strength of metals although their ductility is usually reduced simultaneously. Here we report that the plastic strain of Zr41Ti14Cu12.5Ni10Be22.5 （at.%） bulk metallic glasses has been increased from 0.3% for the as-cast sample to 2.5%-8.0% for samples that have experienced pre-deformation under constrained conditions. The pre-deformed glassy alloys possess more free volume and abundant introduced shear bands,which are believed to promote the activation of shear bands in post-deformation and result in an increase in plasticity. The orientation of the pre-introduced shear bands relative to the loading direction will affect the deformation behavior of pre-deformed samples. The present results show that pre-deformation of this glassy alloy will result in work toughening. This work toughening effect can be removed by isothermal annealing at a sub-Tg （glass transition） temperature,which causes annihilation of free volume and healing of shear bands.

关 键 词：大块金属玻璃 增韧效果 变形过程 自由体积 非晶合金 玻璃化转变 预变形 剪切带 

分 类 号：TG139.8[一般工业技术—材料科学与工程] TD353.6[金属学及工艺—合金]