【目的】研究不同形式的应力对位错运动形式的影响。【方法】通过添加空位自由能项修正晶体相场模型(Phase-field-crystalmodel,PFCmodel),得到空位晶体相场法模型(Vacancyphase-field-crystalmodel,VPFCmodel),并采用VPFC模拟小角度晶界(GrainBoundary)在外加单方向应力作用下的变形过程。【结果】在外加单方向应力作用下,小角度晶界位错组作攀移运动时系统自由能增加,位错组滑移时出现系统自由能下降和位错反应等现象。x方向拉应力促使位错发生负攀移,压应力促使位错发生正攀移。【结论】VPFC模型可有效模拟晶界位错、空位等微结构演化过程。
【Objective】T h e influence of different f o r m s of stress o n dislocation m o v e m e n t w a sstudied.[MethodslBy adding a vacancy free energy t e r m,w e obtained a n e w m o d e l of vacancyph a s e-field-crystal(V P F C),w h i c h w a s used to simulate the deformation process of low-anglegrain b o u n daries(G B s)un d e r a single direction stress.【Results】T h e simulation results s h o wthat the free e n ergy of s y s t e m increases w h e n dislocations climb o n G B s w h e r e a s the free energy decreases w h e n dislocations glide with the appearance of dislocations reaction.T h e tensilestress of x direction p r o m p t s dislocations to negative climb i n g,a n d compressive stress o n thecontrary.【Conclusion】T h e V P F C m o d e l can effectively simulate the microstructure evolutionprocess of grain b o u n d a r y dislocations a n d vacancies.