Ti_(75)Al_(25)合金微观结构演变的分子动力学模拟

Molecular dynamics simulation of microstructure evolution in Ti_(75)Al_(25) alloys

本文利用分子动力学模拟方法,研究了液态Ti_(75)Al_(25)合金在不同冷却条件下形成晶体及非晶的过程(Q1:1.0×10^(13)K Ks^(-1),Q2:1.0×10^(11)Ks^(-1)).利用平均原子体积、双体分布函数、键角分布函数、键对分析和Voronoi多面体方法研究了微观局域结构随温度的变化关系.研究发现:在Q1冷却过程中,液态Ti_(75)A1_(25)合金在1000 K发生玻璃化转变,形成非晶结构;而在Q2冷却过程中,液态Ti_(75)Al_(25)合金发生结晶,并最终形成hcp晶体结构.

The structural transitions of Ti75Al25 during two different quenching processes （Q1： 1.0×1013 Ks-1, Q2： 1.0×1011 Ks-1） were studied by using molecular dynamics simulations. This work gives the structural properties, including the average atomic volume, pair-correlation function, bond-angle distribution function, Honeycutt-Andersen （HA） and Voronoi indices, and temperature dependence. Our results indicated that the liquid was frozen into glass state at the temperature about 1000 K under the quenching condition Q1. While the liquid Ti75Al25 transformed to hcp phase at the temperature under the quenching condition Q2.