Simulation study on temperature field and microstructure of Ti-6Al-4V alloy round ingot during EBCHM
Simulation study on temperature field and microstructure of Ti-6Al-4V alloy round ingot during EBCHM
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DOI：
10.1088/2053-1591/abeb4d
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发表时间：
2021-04
影响因子：
2.3
通讯作者：
B. Peng;Xiang-Ming Li;Xian Wang;J. Mo;Lei Luo
中科院分区：
文献类型：
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作者：
B. Peng;Xiang-Ming Li;Xian Wang;J. Mo;Lei Luo
Ti-6Al-4V圆锭在电子束冷炉熔炼过程中的凝固组织直接决定了铸锭的质量和后续卷材的性能。本文采用元胞自动机有限元(CAFE)方法对Ti-6Al-4V铸锭的凝固组织进行了数值模拟。首先，建立了数学模型并进行了数值求解。其次，研究了浇注温度、拉速等工艺参数对凝固组织的影响。结果表明，数值模拟得到的微观组织与实验结果吻合较好。在拉速一定的情况下，降低浇注温度有利于细化晶粒，减少Al的挥发量。随着拉拔速度的提高，晶粒数先增加后减少，但平均晶粒度先减小后增大。此外，最大晶粒度随拉伸速度的增加而单调增加。当浇注温度为170 0℃，拉速为4×10−4m S−1时，可获得细小、细小的凝固组织。
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 °C and the pulling speed of 4 × 10−4 m s−1.