Numerical simulation of EBCHM for the large-scale TC4 alloy slab ingot during the solidification process

Abstract

A mixed Lagrangian and Eulerian algorithm (MILE) is used to simulate the temperature field during the solidification process of the large-scale Ti-6Al-4V alloy slab ingot in electron beam cold hearth melting (EBCHM). Based on the finite element (FE) method coupled with the cellular automation (CA) model, the microstructure evolution of the ingot is obtained in this paper. The simulated results show that with the pulling speed increasing from 1 × 10−4 m/s to 3.5 × 10−4 m/s, the liquidus depth increases from 0.64 cm to 0.70 cm, the length of the transition region increases and the mean grain size is found to increase. With the pouring temperature increasing from 1953 K to 2013 K, the liquidus depth increases from 0.42 cm to 1.34 cm and the length of the transition region increases, whereas the depth of mushy zone decreases. The region near the bottom of the ingot has finer grains for the non-steady solidifying state of TC4 alloy. Moreover, the role of pulling speed is much greater than that of pouring temperature on the microstructure evolution during EBCHM for large-scale TC4 alloy slab ingot.