摘要
Creep deformation can be classified as homogeneous flow and inhomogeneous flow in bulk metallic glass(BMG).In order to understand the conversion conditions of the two types of creep deformation,the effect of loading rate on the creep behavior of a Ti_(40)Zr_(10)Cu_(47)Sn_(3)(at.%)BMG at ambient temperature was investigated using nanoindentation and molecular dynamic simulation.Results indicate that at low loading rates,many serrations appear in loading stage,leading to inhomogeneous serrated flow in the creep stage.When the loading rate is high enough,the creep deformation tends to be homogeneous.The related mechanism responsible for the rate-dependent creep behavior is attributed to the number of pre-existing major shear bands which is influenced significantly by the loading rate.
大块金属玻璃中的蠕变变形可分为均匀流动和非均匀流动。为了理解两种蠕变变形的转化条件,使用纳米压痕试验和分子动力学模拟研究加载速率对Ti_(40)Zr_(10)Cu_(47)Sn_(3)(摩尔分数,%)大块金属玻璃室温蠕变行为的影响。结果发现,在低加载速率下,加载阶段出现很多的锯齿流动,导致蠕变阶段出现非均匀的锯齿流动;而当加载速率足够高时,蠕变变形趋向于均匀流动。详细讨论与速率相关的蠕变行为的相关机制,发现关键因素是预先存在的主要剪切带的数量,该数量受加载速率的影响较大。
基金
supported by the National Key Research and Development Program of China(No.2016YFB1100103)
the National Natural Science Foundation of China(No.51771233)
Key Research and Development Program of Hunan Province,China(No.2016JC2003)
China Postdoctoral Science Foundation(No.2018M633164)
Fundamental Research Funds for the Central Universities of Central South University,China(Nos.2018ZZTS127,CX20190190,2019ZZTS134)。
