摘要
利用分子动力学方法研究了双晶铜在单向拉伸载荷作用下弹性性能的应变率效应和尺寸效应.结果表明:随着加载应变率的改变,纳米双晶铜的初始弹性模量在低应变率区和高应变率区表现出不同的规律.在低应变率区,弹性模量基本不随应变率的变化而变化;但在高应变率区,弹性模量随应变率的增大而增大,弹性模量和加载应变率之间满足近似的对数线性关系.因此,存在一个控制弹性模量应变率效应的应变率阈值.进一步的研究发现,双晶纳米铜的应变率阈值随着截面尺寸的增大而减小,具有明显的尺寸依赖性.
Molecular dynamic simulations were used to investigate the effect of strain rate and size on the mechanical properties of nano-bi-crystal Cu under uni-axial tension. The results indicate that the initial elastic modulus shows different changing laws in different strain rate regions. The elastic modulus almost maintains invariable in the region of lower strain rate; however, it becomes larger with the increase of strain rate in the region of higher strain rate. Therefore, a strain rate threshold, which controls the strain rate effect on elastic modulus, exists in the process of tension. Moreover, it is found that the elastic modulus is close to linear to the natural logarithm of strain rate. Further study shows that larger cross section results in lower strain rate threshold and the strain rate threshold shows obvious dependence to the cross section.
出处
《固体力学学报》
CAS
CSCD
北大核心
2009年第3期231-235,共5页
Chinese Journal of Solid Mechanics
基金
教育部新世纪优秀人才支持计划项目(NCET-06-0645)
湖北省杰出青年基金项目(2007ABB010)
关键词
双晶铜
应变率效应
尺寸效应
分子动力学
bi-crystal Cu, strain rate effect, size effect, molecular dynamic
