拉应力作用下晶界位错运动过程的晶体相场模拟

【目的】研究晶界位错在受到拉应变作用下的运动规律。【方法】采用晶体相场(Phase-field-crystal,PFC)方法研究拉应力作用下位错的动态演化过程,分析演化过程体系自由能。【结果】改变拉应力的施加方向,沿x轴施加拉应力时,位错运动呈现"左上右下"运动趋势,沿y轴施加拉应力时,位错运动呈现"左下右上"运动趋势。改变拉应力的施加方向对位错的运动及自由能曲线产生明显的影响。最终位错都运动到液相区,模拟区域成完整单晶。【结论】拉应变施加导致位错运动,体系能量上升,在方向不同的正应力的作用下,位错运动方式不同,体系原子之间跟随着外力场的作用作耦合运动,实现施加拉应变的物理效果。

Phase-field-crystal Simulation of Grain Boundary Dislocation Motion Under Tensile Stress

Objective]The motion law of the grain boundary dislocation under the action of the tensile strain is analyzed.Methods]The phase-field-crystal(PFC)method is used to study the dynamic evolution of the dislocation of the tensile stress,and the free energy of the evolution process is analyzed by using the continuous density field.Results]When tensile stress is applied along the x axis,the dislocation movement trends to up at the left and down at the right.When tensile stress is applied along the y axis,the dislocation movement appears to down at the left and up at the right.Changing the direction of applied tensile stress affects remarkably on dislo-cation movement and free energy curve.Finally,all of the dislocation move to liquid phase and the simulation area becomes into a complete single crystal.Conclusion]The tensile strain is ap-plied to cause the dislocation motion,the energy of the system is increased,and the dislocation motion is different under the action of different normal stress.With the interaction between the atoms and the external force field,the physical effect of the tensile strain can be seen.