Ti-6Al-4V三元合金焊接熔池凝固组织模拟

Solidification Microstructure Simulation of Ti-6Al-4V Ternary Alloy Welding Pool

将二元合金元胞自动机模型与热力学相平衡求解软件相结合,提出了一种三元合金元胞自动机模型。对模型的稳定性进行了验证,模拟了Ti-6Al-4V三元合金焊接熔池凝固过程中枝晶的生长形貌、溶质浓度的分布以及扰动振幅对枝晶生长的影响,并进行了金相实验验证。结果表明,模型稳定性良好,能够实现三元合金焊接熔池凝固过程的数值模拟;熔池中枝晶择优生长显著,且存在晶界偏析现象;Al元素与V元素在液相中的浓度分布规律大致相同;随着扰动振幅的增大,熔池中的枝晶数量逐渐增加,枝晶臂间距减小,竞争生长进一步加强;模拟结果与实验结果基本吻合。

Based on the binary alloy cellular automaton model,combined with the thermodynamic phase equilibrium software,a ternary alloy cellular automaton model was proposed.The stability of the model was verified.The morphology of dendritic growth,the distribution of solute concentration and the effect of disturbance amplitude on dendritic growth during solidification of the welding pool of Ti-6 Al-4 V ternary alloy were simulated.And carried out metallographic experiments to verify.The results show that the model is stable and can realize the numerical simulation of solidification process in the weld pool of ternary alloy,and the preferred growth of dendrite in the weld pool is remarkable and there is grain boundary segregation.The concentration distribution of Al and V in the liquid phase is approximately the same.As the amplitude of the disturbance increases,the number of dendrites in the molten pool increases gradually,the distance between the dendrite arms decreases,and the competitive growth further strengthens.The simulation results are basically consistent with the experimental results.