Investigation on crack propagation in single crystal Ag with temperature dependence
Investigation on crack propagation in single crystal Ag with temperature dependence
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DOI：
10.1557/jmr.2015.325
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发表时间：
2015-11
影响因子：
2.7
通讯作者：
Xuefeng Liu;Jin Bao Wang;L. Sun;Ying Zhang;Meiling Tian;X. He
中科院分区：
文献类型：
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作者：
Xuefeng Liu;Jin Bao Wang;L. Sun;Ying Zhang;Meiling Tian;X. He
采用分子动力学模拟方法，研究了不同温度下预裂纹单晶Ag在I型载荷作用下的裂纹扩展行为。模拟结果表明，裂纹扩展行为对外界温度敏感。在0 K时，裂纹以脆性方式扩展。首先观察到裂纹尖端钝化和空洞的产生，然后空洞生长并与主裂纹连接，这导致主裂纹的扩展和脆性破坏立即没有任何微观结构演化。随着温度的升高，裂纹扩展过程中空穴形核和位错发射增多。单晶Ag的变形可以被认为是由于位错发射引起的塑性变形。裂纹扩展动力学表征周围的裂纹尖端的原子的微观结构的演变也被示出。最后，研究表明，单晶Ag的应力随裂纹长度的变化是同步的。
Crack propagation behaviors in a precracked single crystal Ag under mode I loading at different temperatures are studied by molecular dynamics simulation. The simulation results show that the crack propagation behaviors are sensitive to external temperature. At 0 K, the crack propagates in a brittle manner. Crack tip blunting and void generation are first observed followed by void growth and linkage with the main crack, which lead to the propagation of the main crack and brittle failure immediately without any microstructure evolution. As the temperature gets higher, more void nucleations and dislocation emissions occur in the crack propagation process. The deformation of the single crystal Ag can be considered as plastic deformation due to dislocation emissions. The crack propagation dynamics characterizing the microstructure evolution of atoms around the crack tip is also shown. Finally, it is shown that the stress of the single crystal Ag changes with the crack length synchronously.