激光熔凝过程中三维温度场的数值模拟

Numerical Simulation of Three-dimensional Temperature Field in Laser Melting Process

采用有限元法,模拟计算了激光表面熔凝单晶合金材料中的三维温度场分布,得到了材料表面及截面的温度梯度分布,为激光熔凝过程中CET转变及液固相变过程中温度梯度G的变化提供了理论依据。将材料热物性参数随温度的变化引入计算模型,并得到了其对计算结果的影响,为下一步残余应力的数值模拟做了预研准备。计算结果表明:随温度变化的材料的热物性参数对温度梯度G的影响较大;在单晶合金凝固过程中,材料内温度梯度G对CET转变起关键作用;模拟结果与实验测量结果吻合很好。

Three-dimensional transient temperature and the temperature gradient fields in a laser remelted DD3 sample are calculated via FEM method, which is highly important to the CET transition during the solidification of the single crystal alloy. The temperature on the surface were also measured experimentally. In the calculation, the tem- perature dependent physical parameters are used. It is shown that the dependence of the physical parameters on the temperature ~radient is great. The calculated temperature profiles agree well with the experimental results.