Abstract:

Titanium alloys are widely used in the aerospace field due to their high strength, low density, corrosion resistance and other excellent properties. Therefore, it is necessary to theoretically study the evolution of titanium alloys for the quantitative design of new titanium alloys. In this paper, using the valence electron structure parameters calculated by Yu's theory, combined with the rules of cellular automata, a simulation method of the Ti?2Nb alloy β?phase solid solution microstructure was established, and he microstructures of Ti?2Nb alloys at 1 000, 1 050, 1 100, 1 150 and 1 200 ℃ were simulated. The research results show that the model method can associate the phase structure unit with the nucleation and growth of the β microstructure; the quantitative relationship between the number of nucleation points in theβmicrostructure and the solid solution temperature can be characterized by the binding energy of the phase structure unit calculated by Yu's theory; the evolution of the grain size of the β?phase microstructure with the solution time can be correlated by the simulation step. These studies can provide a reference for the establishment of a quantitative relationship between alloy composition， preparation process， structure， performance.

Key words: Yu's theory, Cellular automata, Microstructure simulation, Phase structure unit

摘要：

钛合金因具有高强度、低密度、耐腐蚀等优良性能而广泛应用于航空航天领域，因此从理论上研究钛合金组织演变规律对新型钛合金的定量设计十分必要。利用余氏理论计算价电子结构参数，结合元胞自动机规则，建立了Ti?2Nb合金β相组织模拟方法，对Ti?2Nb合金在1 000、1 050、1 100、1 150、1 200 ℃固溶时的微观组织进行了模拟。结果表明，该模型能够将相结构单元与β相组织形核长大建立关联；β相组织形核点数量与固溶温度的定量关系式可以通过余氏理论计算的相结构单元结合能进行表征；β相组织的晶粒尺寸随固溶时间的演变可以通过模拟步长建立关联。研究结果可为合金成分、制备工艺、组织、性能定量关系的建立提供可借鉴的思路。

关键词: 余氏理论, 元胞自动机, 组织模拟, 相结构单元