BCC晶体中韧位错运动特性的分子动力学模拟

DYNAMIC CHARACTERISTICS OF EDGE DISLOCATION IN BCC METALS BY MOLECULAR DYNAMICS

采用镶嵌原子法 (EAM) ,采用沿 <111>方向插入两层 (2 11)半原子面的方法形成位错 ,模拟金属Mo中韧位错的运动特性 .模拟大于Peierls Nabarro应力时不同剪切力下的韧位错运动速度及相同剪切力下不同温度时韧位错运动速度 ,结果表明 :剪切力越大 ,韧位错运动速度越大 ;温度对韧位错运动有明显的阻碍作用 ,在相同剪切力下 ,随着温度的升高 ,韧位错运动速度减小 ,即拖动系数B(T)随温度升高而增大 .随剪应力增大 ,B(T)变化趋势减缓 .

The dynamics characteristics of edge dislocation in Mo metals are simulated through inserting two (211) hemi-atom planes along the <111>o form the dislocation. Through the embedded atom method (EAM), the edge dislocation velocity is simulated under different shear stress which is larger than the Peierls-Nabarro Stress. The dislocation velocity at different temperatures is also simulated. The results show that the edge dislocation velocity increases with the shear stress decreases with the temperature under a certain shear stress, namely, the drag coefficient increases with the temperature.As the shear stress increases, the variation of B(T) becomes flat.