Deformation induced structural evolution in bulk metallic glasses  

作　　者：WANG Gang MATTERN Norbert BEDNARCI Jozef XIA Lei ZHAI QiJie DONG YuanDa ECKERT Jvrgen 

机构地区：[1]Laboratory for Microstructures, Shanghai University, Shanghai 200444, China [2]Leibniz-Institute IFW Dresden,Institute for Complex Materials,Dresden D-01069,Germany [3]HASYLAB at DESY,Hamburg D-22603,Germany [4]TU Dresden,Institute of Materials Science,Dresden D-01062,Germany

出　　处：《Chinese Science Bulletin》2011年第36期3952-3959,共8页

基　　金：the Alexander von Humboldt Foundation for financial support;supported by the National Natural Science Foundation of China (50731008)

摘　　要：The structural behavior of binary Cu50Zr50 and ternary Cu50Zr45Ti5 bulk metallic glasses (BMGs) under applied stress was investigated by means of in-situ high energy X-ray synchrotron diffraction. The components of the strain tensors were determined from the shifts of the maxima of the atomic pair correlation functions (PDF) in real space. The anisotropic atomic reorientation in the first-nearest-neighbor shell versus stress suggests structural rearrangements in short-range order. Within the plastic deformation range the overall strain of the metallic glass is equal to the yield strain. After unloading,the atomic structure returns to the stress-free state,and the short-range order is identical to that of the undeformed state. Plastic deformation,however,leads to localized shear bands whose contribution to the volume averaged diffraction pattern is too weak to be detected. A concordant region evidenced by the anisotropic component is activated to counterbalance the stress change due to the atomic bond reorientation in the first-nearest-neighbor shell. The size of the concordant region is an important factor dominating the yield strength and the plastic strain ability of the BMGs.The structural behavior of binary Cu50Zr50 and ternary Cu50Zr45Ti5 bulk metallic glasses （BMGs） under applied stress was investigated by means of in-situ high energy X-ray synchrotron diffraction. The components of the strain tensors were determined from the shifts of the maxima of the atomic pair correlation functions （PDF） in real space. The anisotropic atomic reorientation in the first-nearest-neighbor shell versus stress suggests structural rearrangements in short-range order. Within the plastic deformation range the overall strain of the metallic glass is equal to the yield strain. After unloading,the atomic structure returns to the stress-free state,and the short-range order is identical to that of the undeformed state. Plastic deformation,however,leads to localized shear bands whose contribution to the volume averaged diffraction pattern is too weak to be detected. A concordant region evidenced by the anisotropic component is activated to counterbalance the stress change due to the atomic bond reorientation in the first-nearest-neighbor shell. The size of the concordant region is an important factor dominating the yield strength and the plastic strain ability of the BMGs.

关 键 词：大块金属玻璃 结构演变 形变诱导 塑性变形能力 应力各向异性 块体非晶合金 原子结构 应变张量 

分 类 号：TG139.8[一般工业技术—材料科学与工程] U463.341[金属学及工艺—合金]