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综述了TiAl相图中的亚稳相及其对于相图绘制的干扰,并结合了近十年的研究成果分析了亚稳相的形成原因及亚稳相的鉴别,第一性原理计算具有深刻的物理学内涵,利用最基本的量子力学参量对各相的结构稳定性、机械稳定性进行计算,得出了各个相的存在温度及存在范围。对于Al5Ti3相的转变及形成都进行了理论计算,并成功解释了实验现象,同时也提供了Al_5Ti_3相作为亚稳相的证据。另外证明了h-Al_2Ti相为稳定相的证据,这对于相图的绘制具有重大的借鉴意义。利用Al5Ti3相及h-Al_2Ti相的成功经验,将第一性原理用于解释Al_3Ti相的稳定性及形成过程。
The metastable phase in TiAl phase diagram and its interference on the phase diagram drawing are reviewed. Combined with the research achievements of the past ten years, the formation reason of metastable phase and the identification of metastable phase are analyzed. The first-principle calculation has deep Of the physical connotation, the use of the most basic quantum mechanical parameters of the structural stability of each phase, the mechanical stability calculated the existence of the existence of each phase temperature and scope. The Al5Ti3 phase transformation and formation are theoretically calculated, and the experimental phenomena are successfully explained, at the same time, the evidence of the Al_5Ti_3 phase is also provided as the metastable phase. In addition, it is proved that h-Al_2Ti phase is a stable phase, which is of great significance to the drawing of phase diagram. Based on the successful experience of Al5Ti3 phase and h-Al2Ti phase, the first principle is used to explain the stability and formation process of Al3Ti phase.