激光与光电子学进展, 2020, 57 (1): 011403, 网络出版: 2020-01-03
选区激光熔化激光功率对316L不锈钢熔池形貌及残余应力的影响 下载: 1459次
Effect of Laser Power for Metal Selective Laser Melting on Morphology of 316L Stainless Steel Molten Pool and Residual Stress
激光技术 激光选区熔化 工艺参数 熔池形貌 残余应力 laser technique selective laser melting process parameters molten pool morphology residual stress
摘要
针对选区激光熔化(SLM)工艺参数的匹配性对成形质量的影响,选取三种激光功率在不同的扫描速度和扫描方式下进行实验,研究了激光功率对熔池形貌及残余应力的影响。结果表明:随着激光功率增大,熔池的几何尺寸和成形件中的残余应力均变大。这主要是因为在上述参数序列下,随着激光功率增大,热流密度增大,相同层厚与截面下的温度梯度增大,熔池温度升高,熔池尺寸变大,从而导致成形件熔融时的晶面夹角及晶界间距较大,进而产生了较大的热应力,成形件冷却凝固后的残余应力过大。在实际应用中,通过合理设计匹配的工艺参数,可以得到较适合的熔池几何尺寸(即较合理的温度梯度分布),从而减小热应力,进而减小残余应力,得到成形质量较高的SLM工件。
Abstract
Considering the influence of matching of process parameters in selective laser melting (SLM) on forming quality, we choose three laser powers and conduct experiments at different scanning speeds and scan modes. The effect of laser power on the morphology of molten pool and residual stress is studied. Results show that an increase in the laser power leads to a corresponding increment in residual stress on formed parts and size of the molten pool. The main reason is that the heat flux density increases with the increasing laser power, the temperature gradient increases under the same thickness and cross section, and the temperature of the molten pool and its size increase. This results in a large interphase angle between crystal faces and large spacing between grain boundaries of different formed parts. It also results in excessive residual stress after cooling and solidification of the formed part corresponding to great thermal stress. Therefore, the thermal and residual stresses can be decreased by rationally selecting and matching the process parameters. Consequently, high-quality SLM parts can be produced.
边培莹, 尹恩怀. 选区激光熔化激光功率对316L不锈钢熔池形貌及残余应力的影响[J]. 激光与光电子学进展, 2020, 57(1): 011403. Peiying Bian, Enhuai Yin. Effect of Laser Power for Metal Selective Laser Melting on Morphology of 316L Stainless Steel Molten Pool and Residual Stress[J]. Laser & Optoelectronics Progress, 2020, 57(1): 011403.