低Al含量Ti-Al合金相变行为的分子动力学模拟

利用分子动力学模拟研究了Ti-5Al和Ti-10Al两种合金的β→α相变过程。比较分析了不同Al含量下相变过程的体系内能、径向分布函数、不同晶体结构相对含量的变化以及晶体结构的演化。结果表明:Ti-10Al较Ti-5Al更快发生α相形核析出,体现出实际相变过程中Al作为α相稳定元素的作用;β→α的结构转变通过{110}β面原子层间的相互滑移发生,并伴随一定畸变,新相与母相间晶体学关系符合{0001}α//{110}β;新相中易形成层错、孪晶等晶体缺陷,以消除部分相变过程中畸变引起的应力。

Molecular Dynamics Simulation on Phase Transition of Ti-Al Alloy

The β→α phase transition processes of Ti-5Al and Ti-10Al were studied by molecular dynamics simulation.The phase transitions of different Al contents were studied by the internal energy,radial distribution function and the contents of different structures.The evolution of the crystal structure during the phase transition was also observed and analyzed.The results show that the nucleation of Ti-10Al occurs faster than Ti-5Al,and Ti-10Al has a higher amount of precipitation of α phase;the phase transition process involves the shuffling of {110}β and is accompanied by a distortion;the crystallographic relationship between new phase and parent phase accords with {0001}α$$$${110}β;stacking faults and twin crystals are easily formed to reduce the stress caused by the phase transition.