纳米级铱单晶不同温度拉伸的分子动力学解析

摘要

针对面心立方金属铱单晶独特的韧脆变形特征，采用分子动力恘方法研究了纳观尺度下的铱单晶在不同温度下的拉伸变形行为。通过分析不同温度拉伸过程中的应力应变关系，势能变化和原子构型图，认为随着温度的上升，纳米级铱单晶沿[100]晶向的弹性模量逐渐下降，抗拉强度也逐渐降低。温度为300 K时拉伸变形过程中在晶体内仅有少量空位和位错产生，600和800 K拉伸变形过程中在晶体内有滑移，位错和空位产生。%Single crystal iridium with fcc crystal structure displays an unique ductile-brittle deformation profile. The temperature effects on the deformation behavior of nano-sized single crystal iridium have been investigated in the present work by using the molecular dynamics method. From the stress-strain curves, variation of potential energy and snapshots of the model during tension, it can be seen that the elastic modulus along the [100] crystal orientation and the strength of nano-sized single crystal iridium decrease as the temperature rises. There were only a few vacancies and dislocations produced during deformation at 300 K, while slippings, dislocations and vacancies were formed at 600 and 800 K.