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运用分子动力学方法研究单晶γ-Ti Al合金的裂纹扩展行为,模拟时采用嵌入原子势方法,结合原子轨迹图、能量演化图以及应力-应变曲线,分析不同孔洞尺寸对裂纹扩展过程的影响。结果表明:随着孔洞半径增大,裂纹的启裂应力值减小;裂纹与孔洞结合后,R=0.4001 nm时,孔洞变形后在孔洞边界的中心产生裂纹,沿[100]方向扩展至材料断裂,裂纹扩展中出现子母裂纹传播现象;R=0.8002 nm时,孔洞变形后在一角处产生裂纹,沿[100]方向扩展至材料断裂;R=1.2003 nm时,孔洞变形后在两个角处产生裂纹,沿[110]和[110]方向扩展,[110]方向裂纹扩展中出现子母裂纹传播现象,且边界产生子裂纹并与该方向裂纹汇合后扩展至材料断裂;此外孔洞抑制裂纹扩展。
The crack growth behavior of single-crystal γ-TiAl alloy was investigated by molecular dynamics method. The simulation was using the method of intercalation of atomic potential and the atomic orbitals, energy evolution and stress-strain curves to analyze the influence of different pore sizes on crack propagation . The results show that the crack initiation stress decreases with the increase of the hole radius. When the crack is combined with the hole, cracks occur in the center of the hole boundary at R = 0.4001 nm and extend to [100] At R = 0.8002 nm, cracks were formed in the corner and cracked along the direction of [100]. At R = 1.2003 nm, the hole was deformed at both corners Cracks propagate along [110] and [110] directions. Propagation of the propagation of the mother-daughter cracks occurs in the [110] -direction crack propagation, and the sub-cracks are generated at the boundary and confluence with this direction and extend to the material fracture. Expand.