为了从微观原子结构探索γ-TiAl 合金裂纹扩展的机理，研究了恒定加载速度下温度对γ-TiAl 合金中裂纹扩展的影响。采用分子动力学方法对单晶γ-TiAl合金中预置微裂纹的扩展过程进行模拟，研究表明，室温下裂纹呈脆性解理扩展，中、高温时，裂纹在扩展过程中发射位错，裂尖钝化并伴有偏转；随温度的升高，微裂纹由脆性解理扩展向韧性扩展转化，裂纹扩展速率减慢，材料塑性增加；裂尖发射的位错堆积在边界附近，使得位错堆积处萌生空洞缺陷，随着加载的继续，空洞最终长大形成微裂纹，出现边界开裂的现象。
In order to explore the mechanism of crack propagation in the gamma-TiAl from the atomic structure, the effects of temperature on crack propagation of the gamma-TiAl under a constant loading rate is studied in this paper.The propagation process of the preset crack in the single crystal gamma-TiAl was simulated by the method of molecular dynamics,the results show that at room temperature,the crack propagates in a brittle cleavage manner,at the medium or high temperature,the crack launches dislocation during the propagation,and the crack tip blunting and also accompanied by deflection;with the increasing of temperature,the formation of the micro crack growth transformed from brittle cleavage propagation to ductile propagation ,the crack growth rate slows down and the plastic of material increases;the dislocation are emitted from the crack tip accumulates near the boundary and the place where the dislocation pile up will initiate the void defect,with the loading con-tinued,the void eventually grows to micro crack and the phenomenon of the boundary cracking is appeared.
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