选区激光熔化IN738LC合金成形温度场的数值模拟及实验研究

Numerical Simulation and Experimental Research on the Temperature Field of Selective Laser Melting of IN738LC Alloy

摘要:

通过数值模拟根据熔池热行为变化规律对选区激光熔化工艺参数进行优化,是提高成形件质量的有效手段。为此,本论文采用ANSYS的APDL语言建立了全参数化的IN738LC合金选区激光熔化过程温度场有限元分析模型,并通过单熔道成形实验对热源模型进行校核。结果表明：随着激光功率的增加或者扫描速度的减小,粉末吸收的线性能量密度不断增加,熔池中心最高温度升高,熔融金属量增加,熔道形态由不规则断续状向规则连续长条状演化；随着扫描速度的增加或者激光功率的减小,粉末吸收的线性能量密度不断下降,熔体流动能力减弱,熔池宽度与熔化穿透深度也随之减小；有限元模拟与实验结果吻合较好,当激光功率为270 W,扫描速度为1150 mm/s时,单熔道具有连续少缺陷、规则良好的成形形貌。

Abstract:

Optimisation of the parameters of the selective laser melting process based on the variation of the thermal behaviour of the melt pool through numerical simulation is an effective means of improving the quality of the formed parts. So, a fully parametric finite element analysis model of the temperature field of the selective laser melting process for IN738LC alloy was developed in the APDL language of ANSYS, and the heat source model was calibrated by single melt channel forming experiments. The results show that: with the increase of laser power or the decrease of scanning speed, the linear energy density absorbed by the powder increases, the maximum temperature of the melt pool centre increases, the molten metal volume increases, and the melt channel morphology evolves from irregular intermittent to regular continuous long strip; with the increase of scanning speed or the decrease of laser power, the linear energy density absorbed by the powder decreases, the melt flow capacity decreases, and the melt pool width and The FEM simulations are in good agreement with the experimental results. When the laser power is 270 W and the scanning speed is 1150 mm/s, the single melt channel has a continuous and good shape with few defects.