不同温度下Ni3Al中疲劳裂纹扩展机理的原子模拟

Atomic Simulation of Fatigue Crack Propagation at Different Temperature in Ni3Al

采用分子动力学的方法模拟了Ni3Al在不同温度下的疲劳裂纹扩展行为.选取不同初始取向的裂纹模型,对比分析其在不同温度下的裂纹扩展行为.研究结果表明Ni3Al合金在400 K时裂纹尖端主要的变形机制为位错、滑移和空洞,初始取向不同的裂纹,裂纹扩展的方式、裂纹周围的变形特点以及裂纹扩展速率都出现了差异.当温度从400 K升到600 K时,Ni3Al中裂纹的扩展速率随着温度的升高而增加,高温没有改变裂纹前端的滑移系统,却使初始滑移带的数量减少,快速扩展中位错滑移的数量增多.

The fatigue crack propagation behavior of Ni3Al at different temperature is simulated by molecular dynamics simulation.The crack models of different initial orientation are constructed to analyze the crack propagation behavior at different temperature.The simulation results show that the mainly deformation mechanisms of the crack tip in Ni3Al are dislocations,slip and void at 400K,and the initial orientation of crack is different,the mode of crack propagation,the deformation characteristics of crack,and the crack propagation rate are differences.When the temperature rises from 400K to 600K,the crack propagation rate of Ni3Al increase with the increasing of temperature.But the high temperature do not change the slip system of the crack tip.However,the number of the initial slip bands decrease at crack tip as the temperature increasing,and the number of slip bands increase in the rapid expansion of crack.