分子动力学模拟α-Fe拉伸与疲劳裂纹扩展机理

发布时间：2019-03-25 20:47

【摘要】：采用分子动力学模拟方法研究了含(010)[001]和(0-11)[100]型中心裂纹的金属α-Fe分别在拉伸与疲劳载荷作用下裂纹扩展的微观机制.研究发现,在拉伸载荷作用下,(010)[001]型裂纹在钝化的基础上沿着{110}滑移面塑性扩展;(0-11)[100]型裂纹尖端位错沿(011)面发射,裂纹沿(110)表面脆性解理扩展.在循环载荷作用下,(010)[001]型裂纹尖端位错沿着{111}110滑移系扩展,裂纹在裂尖应力集中作用下,沿之字形快速扩展;(0-11)[100]型裂纹扩展方式与拉伸失效时基本一致,裂纹在(110)面内发生快速的脆性解理扩展.两种裂纹扩展过程中都有层错和位错的共同作用.研究表明,(110)表面的表面能最低,是α-Fe的最优解理面.
[Abstract]:The microcosmic mechanism of crack propagation in 伪-Fe with (010) [001] and (0 / 11) [100] central cracks under tensile and fatigue loading was studied by molecular dynamics simulation. It is found that under tensile loading, the (010) [001] crack propagates along the {110} slip surface on the basis of passivation. The (0 / 11) [100] type crack tip dislocations are emitted along the (011) surface and the cracks propagate along the (110) surface brittle cleavage. Under cyclic loading, the dislocation of (010) [001] type crack tip propagates along the {111} 110 slip system, and the crack propagates rapidly along its zigzag under the action of stress concentration at the crack tip. The crack propagation mode of (0 / 11) [100] is basically the same as that of tensile failure, and the crack propagates rapidly in (110) plane by brittle cleavage. Both kinds of crack propagation process have the interaction of stacking dislocation and dislocation. The results show that the surface energy of the (110) surface is the lowest, which is the optimal solution surface of 伪-Fe.
【作者单位】：四川理工学院理学院;四川大学建筑与环境学院;
【基金】：国防基础科学研究项目(B15201320131) 四川理工学院培育项目(2015RC41,2015RC44) 四川省教育厅科研项目(15ZB0207)
【分类号】：O346.1

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