Numerical study of aluminum segregation during electron beam cold hearth melting for large-scale Ti-6 wt%Al-4 wt%V alloy slab ingots

Abstract

To investigate aluminum (Al) segregation in large-scale Ti-6 wt%Al-4 wt%V (TC4) slab ingots produced by electron beam cold hearth melting (EBCHM), a three-dimensional multiphysics model verified with experimental data in the literature has been established. The numerical predictions qualitatively revealed the macrosegregation tendency of Al in the molten and the solidified region at different casting conditions. It was noticed that Al segregation is slightly influenced by increasing casting speed due to the vertical evolution of the pool shape near the inlet. A promising solution for Al segregation control is to limit the Al evaporation loss by decreasing the pouring temperature. The results suggest that for EBCHM with a casting speed of 8 mm/min, as the pouring temperature decreases from 2273 to 2073 K, the segregation degree Фl increases from 0.70 to 0.96 in the pool. As a consequence, the corresponding segregation degree Фc on the solidified cross-section improves (increases from 0.67 to 0.93).