孔洞和空位对单晶铝力学性能影响的分子动力学研究

采用分子动力学方法模拟含孔洞的单晶铝单轴拉伸过程，研究晶向、孔洞体积分数、空位体积分数等对孔洞生长的影响.结果表明：对于不同的晶向，决定孔洞生长变形的微观机制不同.[010]晶向单轴拉伸情况下，形变机制主要是｛111｝面位错引起的堆垛层错；[111]晶向单轴拉伸情况下，形变机制主要是位错的移动、堆积与发射.此外，孔洞及空位的体积分数对[010]、[111]晶向的孔洞生长过程也有着明显的影响.总的来说，随着孔洞或者空位体积分数的增加，材料的杨氏模量变小，屈服强度、屈服应变下降.

Molecular Dynamics Study of Mechanical Properties of Single Crystal Aluminum with Voids and Vacancies

Molecular dynamics simulations are performed for single crystal aluminum with voids and vacancies under uniaxial tension. Effects of crystalline orientation,initial void volume fraction,and concentration of vacancies on growing process of voids are investigated. It indicates that at different orientation, decisive microscopic machanism of void growing is different. At orientation[010], decisive machanism is stacking fault caused by dislocations on {111} surface, while at orientation[111], decisive machanism is movement and accumulation of dislocations.Besides, initial void volume fraction and concentration of vacancies have remarkable influence on growing precess of voids.Totally, macroscopic effective Young's modulus and incipient yield strength decrise with increasing void volume fraction or concentration of vacancies.