不同拉伸方向下单晶镁的分子动力学模拟  

Molecular Dynamics Simulation of Single Crystal Magnesium in Different Tensile Directions

作　　者：刘子晨 毛萍莉[1] 张弛[1] LIU Zichen;MAO Pingli;ZHANG Chi(School of Materials Science and Engineering,2.Key Laboratory of Mg Alloys and the Processing Technology of Liaoning Province,Shenyang University of Technology,Shenyang 110870,China)

机构地区：[1]沈阳工业大学1.材料科学与工程学院,2.辽宁省镁合金及其成形技术重点实验室,沈阳110870

出　　处：《机械工程材料》2025年第4期99-104,共6页Materials For Mechanical Engineering

基　　金：辽宁省教育厅项目(LJKMZ20220467)。

摘　　要：采用分子动力学模拟方法,在温度300 K、应变速率109 s−1条件下,从原子尺度研究了不同拉伸方向([0001]和[1120]晶向)对单晶镁拉伸性能以及变形机制的影响。结果表明:单晶镁的拉伸行为表现出各向异性;沿[0001]晶向拉伸的弹性模量、屈服强度以及发生塑性变形需克服的势能垒较大,出现二次屈服现象,在此方向较难变形,其变形机制为第一次屈服由{1012}拉伸孪晶形核和生长主导,第二次屈服由{1012}-{1011}二次孪晶主导;沿[1120]晶向拉伸的弹性模量、屈服强度和发生塑性变形需克服的势能垒较小,只有一次屈服,在此方向较易变形,其变形机制为初始屈服由{1011}压缩孪晶形核并长大主导,随后在晶体内位错与孪晶的相互作用下出现孪晶界局部应力集中。The effects of different tensile directions([0001]and[1120]crystal directions)on the tensile properties and plastic deformation mechanism of single crystal magnesium at the temperature of 300 K and strain rate of 109 s-1 were studied by molecular dynamics simulation method.The results show that the tensile behavior of single crystal magnesium showed anisotropy.The elastic modulus,yield strength and potential energy barrier that plastic deformation needed to overcome along the[0001]crystal direction were large,and twice yield occurred;deformation was difficult in this direction.The mechanism of plastic deformation along[0001]crystal direction was that the first yield was dominated by the nucleation and growth of the{1012}tensile twin,and the second yield was dominated by the{1012}-{1011}secondary twin.The elastic modulus,yield strength and potential energy barrier that plastic deformation needed to overcome along the[1120]crystal direction were small,and there was only one yield;deformation was easy in this direction.The tensile plastic deformation mechanism along[1120]crystal direction was that the initial yield was dominated by the nucleation and growth of the{1011}compression twin,and then the local stress concentration at twin boundaries occurred under the interaction between dislocations and twin crystal in the crystal.

关 键 词：单晶镁 分子动力学 拉伸 各向异性 屈服强度 孪晶 位错 

分 类 号：TG146.22[一般工业技术—材料科学与工程]