纳米多晶镁在不同条件下压缩的分子动力学模拟

为设计和开发具有优异力学性能的镁基纳米结构合金，本文利用Voronoi几何方法构造了晶粒随机取向的纳米多晶镁模型，利用分子动力学软件实现了不同条件下纳米多晶镁的压缩模拟，借助可视化软件对模拟结果进行了相关分析，发现：温度影响晶粒的变化趋势，随着温度升高，晶粒由细化转变为融合长大；压缩速度影响晶粒细化的时间，压缩速度增大，晶粒内部原子仍保持原有结构，只有晶粒边缘处原子位置移动，晶粒细化较晚发生，屈服强度增大，极限应变减小，弹性模量增大；纳米多晶镁中原子位置发生偏移，更易形成FCC结构，产生Shockley不全位错，Shockley不全位错与FCC结构的增长规律呈正比例。

Molecular dynamics simulation of compression of nanocrystalline magnesium under different conditions

To design and develop magnesium-based nanostructured alloys with excellent mechanical properties, a model of nanocrystalline magnesium with random grain orientation was constructed by the Voronoi geometry method. The compression simulation of nanocrystalline magnesium under different conditions was realized by molecular dynamics software. The simulation results were analysed by visualization software. The results show that with the increase of temperature, the grain size changes from refinement to fusion growth; the results show that the compression speed affects the time of grain refinement. With the increase of compression speed, the atoms in the grain still keep the original structure, only the atoms at the edge of the grain move, the grain refinement occurs later, the yield strength increases, the ultimate strain decreases, and the elastic modulus increases; the shift of atomic position in nano polycrystalline magnesium makes it easier to form FCC structure, resulting in Shockley incomplete dislocation, which is in positive proportion to the growth rule of FCC structure.