Cause of hardening and softening in the bulk glassy alloy Zr50Cu40Al10 after high-pressure torsion
Cause of hardening and softening in the bulk glassy alloy Zr50Cu40Al10 after high-pressure torsion
复制标题
DOI：
10.1016/j.msea.2014.12.101
复制
发表时间：
2015-03-11
期刊：
影响因子：
6.4
通讯作者：
Umemoto, Minoru
中科院分区：
文献类型：
--
作者：
Adachi, Nozomu;Todaka, Yoshikazu;Umemoto, Minoru
采用高压扭转（HPT）方法对Zr 50 Cu 40 Al 10块体非晶合金（BGA）进行了变形，导致了严重的塑性变形。HPT工艺后BGA的维氏硬度表明BGA经历了软化和硬化。为了确定提高BGA力学性能的机制，研究了这些HPT诱导现象的原因，同时关注自由体积（FV）和宏观残余应力。虽然在HPT过程之后FV的总分数与引入的剪切应变成比例地增加，但是FV对硬度的影响小得可以忽略。为了控制HPT处理的圆盘中的残余应力，在HPT处理期间使用具有径向凹槽的砧。观察到由于不均匀的塑性流动（即，在塑性变形过程中的应力（具有应变梯度的变形），并且该应力导致观察到的显著程度的软化和硬化。换句话说，通过引入残余应力可以改善BGA的机械性能。(C)2015 Elsevier B.V.版权所有。
The bulk glassy alloy (BGA) Zr50Cu40Al10 was deformed using high-pressure torsion (HPT), which resulted in severe plastic deformation. The Vickers hardness of the BGA after the HPT process indicated that the BGA experienced both softening and hardening. With the aim of identifying mechanisms for improving the mechanical properties of BGAs, the cause of these HPT-induced phenomena was investigated, while focusing on the free volume (FV) and the macroscopic residual stress. Although the total fraction of the FV increased after the HPT process in proportion to the introduced shear strain, the effect of the FV on the hardness was negligibly small. To control the residual stress in HPT-processed disks, anvils with radial grooves were used during the HPT process. It was observed that a residual stress develops in BGAs owing to inhomogeneous plastic flow (i.e., deformation with a strain gradient) during plastic deformation and that this stress causes the significant extents of softening and hardening observed. In other words, the mechanical properties of BGAs can be improved by introducing a residual stress. (C) 2015 Elsevier B.V. All rights reserved.