采用选区激光熔化技术烧结混合后的18Ni300马氏体模具钢粉末和微米SiC粉末，研究加入不同体积分数的SiC粉末对成型试样表面粗糙度、微观结构及力学性能的影响。结果表明，随着SiC体积分数增加，试样顶面的隆起和球化现象加剧，表面粗糙度和孔隙变大，侧面粘粉严重，凝固组织由胞状晶向柱状晶再向枝晶转变，试样的硬度和抗拉强度均高于未添加SiC粉末试样。当加入的SiC粉末体积分数为0.5% 时，试样的硬度和拉伸强度最大，分别达到了371.1 HV和1.51 GPa，相比未添加SiC粉末试样分别提升了7%和54.8%。因此，SiC粉末的加入虽然提高了顶面的粗糙度及孔隙率，但可转变和细化晶粒，增强位错密度提高力学性能，进而提升试样综合使用性能。

In this study, 18Ni300 maraging steel powders and micron silicon carbide (SiC) powders are sintered using selective laser melting technology. Furthermore, the effects of adding different volume fractions of SiC for roughness, microstructure, and mechanical properties are investigated. The results reveal that with the increase in SiC volume fraction, the swelling and spheroidization of the top surface are aggravated, the surface roughness and pores become larger, and the side powder adhesion is serious. Additionally, the solidification structure changes from cellular crystals to columnar crystals and then to dendrites, and the samples of hardness and tensile strength are higher than those without SiC powders. When the volume fraction of SiC powders is 0.5, the hardness and tensile strength samples are the highest, reaching 371.1 HV and 1.51 GPa, which are 7% and 54.8% higher than the sample without SiC powders, respectively. Therefore, while the addition of SiC powders increases the top surface roughness and porosity, it can transform and refine the grain, increase the dislocation density and improve mechanical properties, and then enhance the comprehensive performance of the sample.