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在S i晶体中建立了60°位错偶极子模型并通过Parrinello-Rahm an方法施加剪应力,使用分子动力学方法研究了60°位错在不同的温度和剪应力作用下的运动特性。观察到了位错速度与剪应力成正比关系;而温度对位错速度的影响,随着外加剪应力的不同呈现出三种趋势:(1)低剪应力作用下,位错速度与温度成正比关系;(2)剪应力达到0.6GPa附近时,位错速度与温度呈反比关系,声子拖动效应开始起作用;(3)当剪应力达到2GPa时,位错速度稳定在某一特定值,不再明显随温度的变化而变化。
A 60 ° dislocation dipole model was established in the S i crystal and the shear stress was applied by Parrinello-Rahm an method. The kinematics of the 60 ° dislocation at different temperatures and shear stresses was studied by using molecular dynamics method. It is observed that the dislocation velocity is directly proportional to the shear stress. However, the influence of temperature on the dislocation velocity shows three trends with the applied shear stress: (1) The dislocation velocity is directly proportional to the temperature under low shear stress (2) when the shear stress reaches 0.6GPa, the dislocation velocity is inversely proportional to the temperature and the phonon drag effect begins to work. (3) When the shear stress reaches 2GPa, the dislocation velocity stabilizes at a certain value , No longer noticeable as the temperature changes.