The grain growth mode of titanium alloys remains controversial. In this study, ANSYS and cellular automaton-finite difference code μMatIC were coupled to simulate the multi-scale solidification process of commercial purity titanium and two types of titanium alloys with different solute concentrations. Investment casting of Ti–6Al–4V was carried out in counter-gravity casting method in vacuum environment. Results showed that the grain growth mode of titanium alloys depended on the solute compositions. Grain growth mode of titanium alloys transfers from planar to dendritic with the increased solute. The grain growth morphology of Ti–6Al–4V alloy presents cellular dendritic due to slight solute segregation in the solidification. The predicted grain structure was validated by comparison with the microstructural observation results. Both the prediction and experimental results revealed that equiaxed grains were obtained in investment casting of Ti–6Al–4V regardless of the thickness. The grain size increased with the wall thickness of the cast part.

钛合金的晶粒生长方式仍存在争议。在这项研究中，ANSYS和细胞自动机有限差分码μMatIC耦合以模拟商业纯度钛和两种不同溶质浓度的钛合金的多尺度凝固过程。Ti-6Al-4V的熔模铸造是在真空环境中采用反重力铸造法进行的。结果表明，钛合金的晶粒长大模式取决于溶质的组成。随着溶质的增加，钛合金的晶粒生长模式从平面转变为枝晶。Ti-6Al-4V合金的晶粒生长形态由于凝固过程中的少量溶质偏析而呈现出细胞枝晶状。通过与显微组织观察结果的比较，验证了预测的晶粒结构。预测和实验结果均表明，无论厚度如何，在Ti-6Al-4V熔模铸造中均能获得等轴晶。晶粒尺寸随着铸件壁厚的增加而增加。