含裂纹bcc铁拉伸与疲劳的分子动力学模拟研究  

Molecular Dynamics Simulation for bcc Iron with Central Crack under Uniaxial Tensile and Fatigue Loading

作　　者：袁玉全[1] 曾祥国[2] 胡燕飞[1] 

机构地区：[1]四川理工学院理学院,四川自贡643000 [2]四川大学建筑与环境学院,四川成都610065

出　　处：《江西师范大学学报（自然科学版）》2016年第2期126-132,共7页Journal of Jiangxi Normal University(Natural Science Edition)

基　　金：国防重点基金(B1520132013-1);四川理工学院人才引进项目(2015RC41;2015RC44);四川省教育厅科研课题(15ZB0207)资助项目

摘　　要：采用分子动力学模拟方法研究了含(0 1-1)[011]型中心裂纹的金属α-Fe在拉伸载荷和疲劳载荷作用下裂纹扩展的微观机制.研究结果表明:在拉伸载荷作用下,材料因应力集中导致了由bcc到hcp的相变,裂纹呈现严重钝化扩展现象,整个过程还伴随着层错、孪晶等现象的发生;在循环载荷作用下时,位错沿滑移面(-2 1-1)和(2-1 1)快速发射,从而使得裂尖处应力得以快速释放,疲劳裂纹扩展相当缓慢,裂纹出现止裂现象,整个疲劳加载过程未发现孪晶、相变等现象.The mechanical behaviors around a crack tip for α-Fe with（ 01- 1） [011] centered pre- crack defect under uniaxial tensile and fatigue loading was studied using molecular dynamics simulation method. The phase transition from bcc to hcp was revealed under uniaxial tensile loading,which induced by stress concentration,and the phenomenons of crack tip blunting,stacking faults and twins were found under tensile loading. While under fatigue loading,the fatigue crack grows very slowly because the quick emission of dislocations along the（- 2 1- 1） and（ 2- 1 1） slip plane release the stress around crack tip in time,and there is no twin and phase transition happen throughout the process of fatigue loading. The results indicate that the mechanism of deformation and failure for α-Fe with crack defect is a complicated process,which is the result that many mechanisms act together,such as dislocation emission,loading way,twin and phase transition,etc.

关 键 词：分子动力学 中心裂纹 Α-FE 拉伸 疲劳 LAMMPS 

分 类 号：O483[理学—固体物理]