压力对Ti-Al合金快速凝固过程影响的分子动力学模拟

Molecular Dynamic Simulations of Pressure Effect on Rapid Liquid-Solid Transition Process of Ti-Al Alloy

利用Zope和Mishin提出的Ti-Al势函数形式,采用嵌入原子势描述原子间的相互作用,选取含25%Al原子的Ti-Al无序固溶体为研究对象,开展在两种给定降温速率和不同压力条件下Ti-Al合金快速凝固过程的分子动力学模拟。分析降温过程中体系平均原子能量、平均原子体积、径向分布函数和H-A键对比例的变化规律。从不同角度考察Ti-Al合金快速凝固形成晶态和非晶态合金的过程。研究压力对Ti-Al合金固溶体快速凝固过程及其产物的影响,结果表明:增大压力会减小平均原子体积,降低平均原子能量,同时提高晶化温度或玻璃转化温度。

The interaction between atoms was characterized with the embedded atomic potential. The potential function of Ti-AI was given by Zope and Mishin. An out-of-order Ti-A1 solid solution was investigated. Molecular dynamic simulations for rapid liquid-solid transition process of Ti-A1 alloy were performed in the conditions of two certain descent rates of temperature and different pressures. The variation laws of the average atomic energy, the average atomic volume, the radial distribution function and the percentage of amorphous H-A bonding pairs were analyzed, so that the rapid liquid-solid transition process of Ti-A1 alloy into the crystal or noncrystalline was observed from all conceivable angles. And then, the effects of pressure on the liquid-solid transition process and products were evalua- ted. It is shown that both the average atomic volume and the average atomic energy decrease, but the crystallization temperature or the glass transition temperature increases with the increasing pressure.