Simulation study on temperature field and microstructure of Ti-6Al-4V alloy round ingot during EBCHM

The solidification structure of Ti-6Al-4V round ingot during the electron beam cold hearth melting (EBCHM) directly determines the quality of the ingot and the performance of the subsequent rolled coil. In this paper, the Cellular Automaton Finite Element (CAFE) method is used to numerically simulate the solidification structure of Ti-6Al-4V ingot. Firstly, the mathematical model is established with a numerical solution. Secondly, effects of process parameters including the pouring temperature and pulling speed on the solidification structure are revealed. The results show that the microstructures predicted by the numerical method match the experimental results. For the case of fixed pulling speed, a reduction in the pouring temperature leads to the grain refinement and the decreased volatilization of Al. With an increase of the pulling speed, the number of grains first increases and then decreases, but the average grain size first decreases and then increases. Furthermore, the maximum grain size monotonically increases with increasing the pulling speed. Thus, the fine solidified structure with fine grains can be obtained at the pouring temperature of 1700 degrees C and the pulling speed of 4 x 10(-4 )m s(-1).

Automated summary

In this study, the solidification structure of a Ti-6Al-4V ingot was numerically simulated using the CAFE method, with results showing good agreement with experimental data. It was found that reducing the pouring temperature led to grain refinement and decreased volatilization of Al, while increasing the pulling speed initially increased and then decreased the number of grains, with a corresponding trend of decreasing and then increasing average grain size. Additionally, the maximum grain size consistently increased with higher pulling speeds, indicating that a fine solidified structure with fine grains can be achieved at specific process parameters.