晶体弹性行为的晶体相场模拟

Phase-field-crystal Simulation for Elastic Behavior of Crystals

【目的】研究晶体相场模型中的弹性相互作用过程。【方法】通过连续的密度场,采用晶体相场模型提取和跟踪每个原子在时间演化过程中的位置,再通过求解PFC方程,并运用原子的位移来构建晶体的弹性能。最后通过调优波动参量和阻尼参数β,获得晶体的弹性及粘弹性行为特征。【结果】当β=0.9时,在力F的作用下,晶体响应是有弹性的。位置距离越远,其对应的应变越大,位移变化与原子对应位置大致成正比,具有弹性关系;当β=9时,在力F的作用下,位移变化与原子对应位置服从粘弹性响应关系。通过调优波动参量和阻尼参数,获得晶体的弹性及粘弹性行为特征。【结论】改变阻尼参数β后,可以采用晶体相场模型模拟晶体的弹性及粘弹性行为。

【Objective】Simulation experiments are conducted in p h a s e-field-crystal(P F C)m o d e lto analyze elastic interaction.【M e t h o d s】T h r o u g h the continuous density field,the phase fieldm o d e l is used to extract a n d track the position of each a t o m in the time evolution.T h e P F Cm e t h o d is used to solve the equation?a n d the atomic displacements are used to construct thecrystal elastic e n e r g y.[R e s u l t s J W h e n/?=0.9?the crystal response is elastic un d e r the action offorce F.T h e farther a w a y f r o m the position?the larger the strain island the c h a n g e of displaceme n t is roughly proportional to the position of the a t o m.U n d e r the action of the force F,thec h a n g e of displacement a n d the position of the a t o m correspond to the viscoelastic responsew h e n/?=9.B y tuning w a v e parameters a n d d a m p i n g p a r a m e t e r s?the elastic a n d viscoelastic b e haviorsof crystals are obtained.【Conclusion】After changing the d a m p i n g p a rameter/?,thep h a s e-field-crystal m o d e l can be used to simulatethe elastic a n d viscoelastic behaviors of crystals.