温度对镁单晶孔洞扩展影响的分子动力学模拟

Molecular dynamics simulation of effect of temperature on void propagation of magnesium single crystal

利用分子动力学模拟和嵌入原子方法研究了不同温度下纳米级镁单晶孔洞的扩展和断裂过程。结果表明:温度对体系的势能和屈服强度有明显影响,体系势能和屈服应变随温度升高而增大,屈服强度随温度升高而降低;温度为100 K时,试样塑性变形的方式主要是位错运动;温度为300 K时,塑性变形的方式主要是位错运动以及少量的基面滑移;温度为500 K时,塑性变形的方式主要是非基面滑移;温度为500 K时最终断裂的应变最小,温度为100 K和300 K时最终断裂的应变大致相同。

The propagation and fracture process of void in nanocrystalline magnesium single crystal at different temperatures were investigated by molecular dynamics simulation and atomic embedding method.The results show that the temperature has a significant effect on the potential energy and yield strength of the system,and the potential energy and yield strain of the system increase with the increase of temperature,but the yield strength decreases.When the temperature is 100 K,the plastic deformation mode of the specimen is mainly dislocation movement,and when the temperature is 300 K,the plastic deformation is mainly dislocation movement and a small amount of base plane slip,while at 500 K,the plastic deformation is mainly non-basal slip.The strain of final fracture at 500 K is the smallest,and the strain of final fracture at 100 K and 300 K is approximately the same.