论文部分内容阅读
采用分子动力学(MD)方法研究γ-Ti Al合金中<110>对称倾斜界面的断裂行为,模拟在不同温度与应变速率下垂直界面方向的拉伸变形。结果表明:晶粒的相对取向及晶界特定的原子结构是影响位错形核临界应力的两个主要因素。取向差角度大于90°的Σ3(111)109.5°、Σ9(221)141.1°和Σ27(552)148.4°界面,位错在晶界处形核和扩展;取向差角度小于90°的Σ27(115)31.6°和Σ11(113)50.5°界面,无位错在晶界处形核,当应力达到峰值后界面直接断裂。γ-Ti Al双晶的断裂机制为微裂纹在界面处的形核及沿界面扩展;不同取向差界面的区别在于裂纹前端有无塑性区增韧。
The molecular dynamics (MD) method was used to study the fracture behavior of the <110> symmetric inclined interface in γ-Ti Al alloys and to simulate the tensile deformation in the direction perpendicular to the interface at different temperatures and strain rates. The results show that the relative orientation of grains and the specific atomic structure at grain boundaries are the two main factors affecting the critical stress of dislocation nucleation. (111) 109.5 °, Σ9 (221) 141.1 ° and Σ27 (552) 148.4 ° with an angle difference of more than 90 °. The dislocations nucleate and expand at the grain boundaries. The Σ27 (115 ) 31.6 ° and Σ11 (113) 50.5 °. No dislocations nucleate at the grain boundaries, and the interface breaks directly when the stress reaches the peak value. The fracture mechanism of γ-Ti Al twin is the nucleation of microcracks at the interface and the propagation along the interface. The difference between the different orientation difference interfaces is the presence or absence of plastic zone toughening at the crack front.