Phase field simulations incorporating contributions from chemical free energy and anisotropic interfacial energy are presented for the β→α transformation in Ti-6Al-4 V alloy to investigate the growth mechanism of α lamellae of various morphologies from undercooled β matrix. The α colony close to realistic microstructure was generated by coupling the Thermo-Calc thermodynamic parameters of α and β phases with the phase field governing equations. The simulations show that α lamellar side branches with feathery morphology can form under a certain combination of interfacial energy anisotropy and temperature. α lamellae tend to grow slowly at high heat treatment temperature and become wider and thicker as temperature increase from 800 to 900 °C provided that the interfacial energy anisotropy ratio k_x: k_y was set as 0.1: 0.6. Besides, higher interfacial energy anisotropy can accelerate the formation of α lamellae, and the equilibrium shape of α lamellae changes from rod to plate as the interface energy anisotropy ratio kx: ky vary from 0.1: 0.4 to 0.1: 0.8 under 820 °C. Experiments were conducted to study the α lamellar side branches in Ti-6Al-4 V (Ti-6.01Al-3.98 V, wt.%) and Ti-4211 (Ti-4.02Al-2.52V-1.54Mo-1.03Fe, wt.%) alloys with lamellar microstructure. Electron backscatter diffraction (EBSD) results show that α lamellar side branches and their related lamellae share the same orientation. The predicted temperature range for α lamellar side branches formation under various interfacial energy anisotropy is consistent with experimental results.

提出了结合了化学自由能和各向异性界面能贡献的相场模拟，用于Ti-6Al-4 V合金中的β→α相变，以研究过冷的β基体中各种形貌的α薄片的生长机理。通过将α和β相的Thermo-Calc热力学参数与相场控制方程耦合，可以生成接近实际微观结构的α菌落。仿真表明，在一定的界面能各向异性和温度的共同作用下，可以形成具有羽状形态的α层状侧支。α薄片趋向于在高温热处理温度慢慢成长，成为更宽和更厚为从800至900温度升高℃，条件是该界面能各向异性比ķ _X：k _y设置为0.1：0.6。此外，较高的界面能各向异性可以促进α片的形成，并且在820°C下，随着界面能各向异性kx：ky从0.1：0.4到0.1：0.8的变化，α片的平衡形状会从棒到板发生变化。进行实验以研究Ti-6Al-4 V（Ti-6.01Al-3.98 V，wt。％）和Ti-4211（Ti-4.02Al-2.52V-1.54Mo-1.03Fe，wt。％）中的α层状侧支。％）具有层状微结构的合金。电子背散射衍射（EBSD）结果表明，α层状侧支及其相关的层共享相同的取向。在各种界面能各向异性下α层状侧枝形成的预测温度范围与实验结果一致。