目的 为了获得不锈钢激光选区熔化单道成形质量好的加工参数，提高成形质量。方法 对于316L不锈钢材料的激光选区熔化(SLM)成形，采用离散元方法(DEM)构建颗粒随机分布的三维介观模型，采用流体体积法(VOF)动态追踪SLM成形过程熔池传热、流动和凝固等行为，该模拟考虑相变潜热、热物性参数随温度非线性变化、Marangoni效应，研究了温度梯度引起的表面张力和蒸汽反冲力等现象对熔池液态金属流动和凝固的影响，并对不同激光参数和扫描速度对熔池温度场和内部流动的影响规律进行了分析。结果 当激光功率为150 W、扫描速度为400 mm/s时，激光能使不锈钢粉末充分熔化，凝固后的轨迹形貌连续光滑。通过提高激光扫描速度和降低激光功率使得热输入减小，熔道表面成形出现球化等缺陷。结论 通过单道成形实验观察和分析熔池与熔道的三维尺寸与形貌，有效验证了数值模拟的正确性，较好地预测出SLM过程中的缺陷种类，为深入理解SLM过程中的复杂物理现象和优化工艺参数提供了参考。

Selective Laser Melting (SLM) is a complex additive manufacturing process that involves the melting and solidification of metal powders using a high-energy laser beam. The quality of the SLM process is influenced by various parameters such as laser power, scanning speed, scanning path, and scanning spacing. Changes in these parameters can lead to common defects such as pores, spattering, cracks, surface roughness variations, and balling phenomena. These defects, in turn, can affect the microstructure, surface morphology, and mechanical properties of the manufactured parts.