Cu刃型扩展位错附近局部应变场的原子模拟研究

Atomistic simulation study on the local strain fields around an extended edge dislocation in copper

通过结合virial应变分析技术的准连续介质多尺度模拟方法研究了金属Cu刃型扩展位错的局部应变场.结果表明在距离位错核心几十纳米的区域内晶体处于小变形状态,virial应变计算结果与弹性理论预测结果符合得相当好,当距离位错核心仅几纳米时,晶格畸变加剧,virial应变极大值出现在扩展位错两端的Shockley分位错芯部.进一步分析表明Shockley分位错芯部严重畸变区大致呈长轴7b1、短轴3b1的椭圆形,其中b1为分位错柏氏矢量的长度.

The local strain fields around an extended edge dislocation in copper are studied via the quasicontinuum multiscale simulation method combined with the virial strain calculation techniques. Results show that in the regions, tens of nanometers away from the dislocation, atoms are experiencing infinitesimal strain; virial strain calculation results are consistent with the predictions from elastic theory very well. In the regions near the dislocation, the virial strain fields can outline the core areas of Shockley partial dislocations precisely, which are in the shape of ellipse with a longer axis 7b] and a shorter axis 3bl, where bl is the length of burgers vector of the partial dislocation.