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Ti-6Al-4V是典型的α+β钛合金,不同热处理制度和热加工工艺下可得到形貌各异的微观组织,从而表现出不同的力学性能,深刻理解合金中微观组织的形成机制有助于合金的进一步优化和改造.采用相场方法模拟Ti-6Al-4V合金中片层组织的形成及演化,以热力学数据库和动力学数据库为输入,通过计算定量预测β晶界上已存在初生α相时合金组织随时间的演化.结果表明,在一定条件下,随着时间的延长晶界α向β晶内生长形成片层组织,片状α簇的形貌与界面能各向异性密切相关;晶界取向对片层生长有重要作用,垂直于晶界生长时产生最密集的片层,随倾斜角增大片层加厚且生长缓慢;此外,热处理温度显著改变片层组织形貌,温度越高,片层尖端生长速度越慢,片层间距越大.
Ti-6Al-4V is a typical α + β titanium alloy, different heat treatment system and thermal processing technology can be obtained under different microstructure microstructure, which showed different mechanical properties, a deep understanding of the alloy microstructure formation mechanism Aided by the phase field method to simulate the formation and evolution of the lamellar structure in the Ti-6Al-4V alloy. The thermodynamic database and the kinetic database were used as input to predict the existence of primary α phase, the results show that under certain conditions, the grain boundary α grows to β crystal in the lamellar structure with time prolonging, and the morphology and interfacial anisotropy of lamellar α clusters are close The orientation of the grain boundaries plays an important role in the growth of the lamellae. The lamellae grow thicker and grow slowly along with the increasing of the leaning angle. In addition, the heat treatment temperature significantly changes the lamellar structure, The higher the temperature, the slower the tip growth rate, the greater the lamellar spacing.