bcc-Fe刃型位错偶极子的动力学过程模拟

DYNAMIC SIMULATION OF EDGE DISLOCATION DIPOLE IN BCC-FE

用分子动力学方法模拟了bcc单晶铁中滑移面为(011)晶面、柏氏矢量b-=±[100]的刃型位错偶极子吸引至湮灭的动力学过程.模拟结果显示:沿[100]晶向滑移的正刃型位错穿越Peierls势垒的方式为滑移面上方芯原子沿[111]晶向滑移,滑移面下方芯原子沿[111]晶向滑移;芯原子滑移方向分别偏转为[1 11]和[111]晶向,同时芯能量以格波形式释放.统计了位错运动速度和Peierls势垒随时间或两位错距离的变化。

Molecular dynamics simulations （MD） are used to investigate dynamic process of an edgedislocation dipole in gliding face （011） with Burgers vector b-±[100] in bcc single-crystal iron. Simulation results reveal that.for the positive edge dislocation gliding along direction, the core atoms above the gliding face pass through Peierls potential barrier by slipping along [111] direction and those below the gliding face by slipping along [111] direction; and then slipping directions of core atoms turn to [111] and [111] correspondingly, while the core energy is released by phonon. Velocity and Peierls potential barrier of dislocations, as functions of time and distance between dislocations, are calculated. Results show that for the case of long distance, Peierls potential barrier remains invariable and dislocations glide at a speed of 1.05km/s; for the case of short distance （〈5 b）, Peierls potential barrier reduces rapidly and dislocations begin to accelerate, and before annihilating the velocity of dislocations arrives at 2.31 km/s.