目的 研究Si元素含量对316L不锈钢激光熔覆层凝固行为和显微组织的影响。方法 利用LDF400-2000光纤耦合半导体激光器和ABB机械手组成的激光熔覆系统，在316L不锈钢基体上制备Si元素的质量分数分别为0.8%、1.6%的316L激光熔覆层。使用金相显微镜、扫描电镜(SEM)、电子背散射衍射(EBSD)、透射电镜(TEM)和维氏硬度计，分别从激光束扫描方向(SD)和切向(TD)分析熔覆层的微观组织、晶粒取向、织构和显微硬度。结果 在SD方向，0.8%-Si熔覆层的中下部晶粒呈垂直于底部界面的柱状生长趋势，而顶部晶粒则呈胞状，1.6%-Si熔覆层晶粒的生长模式与0.8%-Si熔覆层类似，但取向更随机。在TD方向，0.8%-Si熔覆层晶粒呈外延状，取向为<100>方向，而1.6%-Si熔覆层则为<111>方向。与0.8%-Si熔覆层相比，1.6%-Si熔覆层内小角度晶界占比更高，超过了50%，在晶粒内部可见被位错缠绕的亚微米颗粒，其硬度也从0.8%-Si熔覆层的199.7HV0.3提升到212.2HV0.3。结论 Si元素的含量对激光熔覆316L凝固行为和组织有着显著影响，改变了熔覆层的凝固模式，使组织结构由粗大外延生长的树枝晶转变为沿温度梯度方向生长的细小晶粒。

In this study, the influence of different mass fractions of silicon (Si) on the solidification microstructure of 316L stainless steel during laser cladding process was investigated in details. A laser cladding system consisting of a LDF400-2000 fiber-coupled semiconductor laser and an ABB manipulator was utilized to deposit a cladding layer containing 0.8% and 1.6% Si on an 316L substrate. Multiple characterization techniques, such as optical microscopy, scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), transmission electron microscopy (TEM), and Vickers hardness testing were employed to assess the microstructure, formation mechanism, grain orientation, texture, and microhardness of the cladding layer both in the scanning direction (SD) and the tangential direction (TD).