Atomic simulations to evaluate effects of stacking fault energy on interactions between edge dislocation and spherical void in face-centred cubic metals
Atomic simulations to evaluate effects of stacking fault energy on interactions between edge dislocation and spherical void in face-centred cubic metals
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DOI：
10.1080/14786435.2018.1472401
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发表时间：
2018-05
影响因子：
1.6
通讯作者：
K. Doihara;T. Okita;M. Itakura;M. Aichi;K. Suzuki
中科院分区：
文献类型：
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作者：
K. Doihara;T. Okita;M. Itakura;M. Aichi;K. Suzuki
摘要本研究通过分子动力学模拟，阐明了层错能（SFE）对面心立方金属晶体结构中不同温度和不同孔洞尺寸下边缘位错与球形孔洞之间物理相互作用的影响。观察到4种不同的相互作用形态，其中：(1)两个部分位错分别脱离空隙，最大应力对应于尾部部分的脱离；(2)两个部分位错分别脱离空隙，最大应力对应于先导部分的脱离；(3)部分位错几乎同时脱离空隙，但未形成微动；(4)部分位错几乎同时从空隙中脱离。随着孔洞尺寸的增大或SFE的增大，相互作用形态的变化顺序与上述顺序一致。观察到临界分解剪切应力（CRSS）的大小及其与SFE的依赖关系由这些相互作用形态决定。在相互作用形态(1)的情况下，采用单个局部位错的Burgers矢量，CRSS的值几乎等于基于线弹性的解析值。用两种部分位错的Burgers向量分析模型得到了CRSS的最大值。
Abstract In this study, molecular dynamics simulations were performed to elucidate the effects of stacking fault energy (SFE) on the physical interactions between an edge dislocation and a spherical void in the crystal structure of face-centred cubic metals at various temperatures and for different void sizes. Four different types of interaction morphologies were observed, in which (1) two partial dislocations detached from the void separately, and the maximum stress corresponded to the detachment of the trailing partial; (2) two partial dislocations detached from the void separately, and the maximum stress corresponded to the detachment of the leading partial; (3) the partial dislocations detached from the void almost simultaneously without jog formation; and (4) the partial dislocations detached from the void almost simultaneously with jog formation. With an increase in void size or SFE, the interaction morphology changed in the above-mentioned order. It was observed that the magnitude of the critical resolved shear stress (CRSS) and its dependence on the SFE were determined by these interaction morphologies. The value of the CRSS in the case of interaction morphology (1) is almost equal to an analytical one based on the linear elasticity by employing the Burgers vector of a single partial dislocation. The maximum value of the CRSS is also obtained by the analytical model with the Burgers vector of the two partial dislocations.