以95W-5Ta混合粉末研究对象，针对95W-5Ta激光粉末床熔融工艺成形过程中存在的热应力较大和变形严重的问题，基于有限元方法对成形中应力场演变过程进行数值模拟. 模拟结果表明，应力变化是一个多重循环过程，增大激光功率和降低扫描速度都会导致热应力增大，分区扫描策略能使热应力均匀分布，避免在零件的敏感区域出现应力集中. 通过开展工艺实验分析影响变形量的因素，发现变形程度对激光功率更加敏感，同时与扫描线长度、层间交错角和扫描策略有关. 试验表明，采用较短的扫描线、67°层间交错角和较小的分区扫描能获得较小的变形量.
In this paper, 95W-5Ta mixed powder is used as the research object. In order to solve the problems of high thermal stress and serious deformation during the forming process of 95W-5Ta laser powder bed fusion (LPBF), numerical simulations are adopted based on the finite element method to simulate the evolution of the stress field in the forming process, and the process experiments are carried out to verify the correctness of the simulation results. The simulation results show that the stress change is a multi-cycle process, increasing the laser power and decreasing the scanning speed will lead to an increase of thermal stress, and the zonal scanning strategy can make the thermal stress uniformly distributed and avoid the stress concentration in the sensitive areas of the part. To analyze the factors affecting deformation, experiments were designed, it was found that the degree of deformation is more sensitive to the laser power, and related to the scan line length, inter-layer intersection angle and scanning strategy. Experiments results showed that a shorter scan line, 67° inter-layer staggering angle and smaller zonal scanning can obtain smaller deformation.
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