数值模拟选区激光熔化加工Inconel 718合金时搭接率对成型质量的影响

发布时间：2018-02-07 12:04

本文关键词： 数值模拟选区激光熔化 Inconel 合金搭接率　出处：《应用激光》2017年02期 　论文类型：期刊论文

【摘要】：一个包含了固体传热和层流的选区激光熔化(Selective Laser Melting,SLM)三维有限元模型被用来模拟选区激光熔化加工单层多道Inconel 718合金粉末的过程,来预测加工过程中激光束的搭接率对成型质量的影响。为了提高模拟结果的准确性,模型中考虑了激光在粉床中的穿透作用、粉床与实体热导率的明显差异、固液相变过程以及由于熔池表面存在温度梯度而引起的Marangoni对流。对Marangoni对流对熔池形貌的影响以及激光束搭接率对成型质量的影响进行了分析和讨论。结果显示,加工过程中熔池内的熔融金属的对流为外向对流,对流的存在使得熔池的深度减小、宽度增加。当激光束的搭接率为30%时,工件内气孔较少,加工质量较好。模拟结果与实验结果相对照,吻合程度较好。
[Abstract]:A selective Laser melting model containing solid heat transfer and laminar flow is used to simulate the process of single-layer multichannel Inconel 718 alloy powder processing by selective laser melting. In order to improve the accuracy of simulation results, the penetration of laser in powder bed and the obvious difference of thermal conductivity between powder bed and solid are considered in the model. The process of solid-liquid phase transition and the Marangoni convection caused by the temperature gradient on the surface of the molten pool are discussed. The influence of Marangoni convection on the morphology of the molten pool and the influence of laser beam lap ratio on the forming quality are analyzed and discussed. During processing, the convection of molten metal in the molten pool is outward convection, which makes the depth of the molten pool decrease and the width increase. When the lap ratio of the laser beam is 30, there are fewer pores in the workpiece. The simulation results are in good agreement with the experimental results.
【作者单位】：北京工业大学;
【基金】：北京市自然科学基金特别资助项目(项目编号:Z140002)
【分类号】：TG665

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