拉伸与疲劳载荷下α-Ti中裂纹扩展机制的原子模拟  

Atomistic simulation of failure mechanism forα-Ti with central crack under uniaxial tensile and fatigue loading

作　　者：袁玉全[1] 曾祥国[2] 胡燕飞[1] 朱彦[3] 

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 [3]四川理工学院自动化与电子信息学院,四川自贡643000

出　　处：《安徽大学学报（自然科学版）》2016年第3期50-57,共8页Journal of Anhui University(Natural Science Edition)

基　　金：国防重点基金资助项目(B1520132013-1);四川理工学院科研项目(2015RC41;2015RC44;2012KY16);四川省教育厅科研项目(15ZB0207;13ZB0132)

摘　　要：采用分子动力学方法模拟研究含3种不同裂纹取向的α-Ti在拉伸载荷和疲劳载荷作用下裂纹扩展的微观机制.研究表明:B(0001)[1-210]裂纹构型通过产生变形孪晶的方式来实现垂直于基面方向的变形,单向拉伸过程中裂尖处有无位错区出现;A(1-210)[10-10]和C(1-210)[0001]裂纹构型的失效过程表明基面位错比柱面位错更容易发射;C裂纹构型循环加载时基面滑移系优先开动,使位错快速发射而释放了裂尖应力,导致裂纹出现止裂现象;含微裂纹α-Ti材料的失效过程是位错形核与发射、缺陷扩展、孪晶变形等共同作用的结果.In this paper, molecular dynamics simulation was performed to study the failure mechanism of the a-Ti with centered pre-craek defect under uniaxial tensile and fatigue loading. Three typical pre-eracks with A（1-210） [10-10], B（0001） [1-210] and C（1-210） [0001] were chosen to simulate the effects of crack orientation on crack growth under these two loading. The deformation twinning was found in crack B, at the same time the dislocation-free zone around the crack tip was found under tensile loads. The results also indicated that dislocation emission in the base plane was easier than that in the cylindrical plane, so the crack growth of orientation C stopped because the dislocation emits rapidly along its base plane releasing the crack tip stress under the fatigue loading. The results showed that the failure mechanism of α-Ti with crack defect was a very complicated process with many interacting factors mixed together, such as dislocation emission, carck growth, deformation twin, and so on.

关 键 词：分子动力学 中心裂纹 Α-TI 拉伸 疲劳 LAMMPS 

分 类 号：O483[理学—固体物理]