Molecular dynamics simulations of void growth in γ-TiAl single crystal
Molecular dynamics simulations of void growth in γ-TiAl single crystal
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DOI：
10.1016/j.commatsci.2013.12.014
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发表时间：
2014-03
影响因子：
3.3
通讯作者：
F. Tang;Hou-Min Cai;Hongchen Bao;H. Xue;W. Lu;Liang Zhu;Z. Rui
中科院分区：
文献类型：
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作者：
F. Tang;Hou-Min Cai;Hongchen Bao;H. Xue;W. Lu;Liang Zhu;Z. Rui
采用分子动力学模拟方法研究了γ-TiAl单晶中球形纳米孔洞的生长及其断裂特性。结果表明，剪切环的发射是空洞长大的主要机制：位错核的不断产生和剪切环的扩展使空洞长大。裂纹起源于空洞表面附近的变形区域。随着裂纹向空洞表面和晶界扩展，γ-TiAl单晶最终断裂。还研究了试样尺寸、应变速率和孔隙体积分数对孔隙增长的依赖性。初始屈服强度随试件尺寸或孔隙体积分数的增大而减小，随应变速率的增大而增大。杨氏模量仅对空隙体积分数敏感。
Molecular dynamics simulation was performed to study the growth of spherical nano-voids and the fracture properties of γ-TiAl single crystal. It is found that the emission of shear loops is the primary mechanism of the void growth: continued production of dislocation cores and the propagation of shear loops make the void grow. Cracks originate from the deformed area near the void surface. As the cracks propagate to the void surface and to the crystal boundaries, γ-TiAl single crystal finally fractures. The dependence of the void growth on the specimen size, strain rate, and void volume fraction was also investigated. The incipient yield strength decreases as the specimen size or void volume fraction increases, but increases with the increase of the strain rate. Young’s modulus is only sensitive to the void volume fraction.