Effect of manufacturing steps on the interfacial defects of laser powder bed fusion 316L/CuSn10

Abstract Manufacturing of 316L/CuSn10/316L sandwich structure was successful completed using a multi-material laser powder bed fusion (L-PBF) system. Intermittent cracks and branch microcracks were found at the interface of forming steel on the copper, while only branch microcracks appear when copper is formed on steel. The defects of these two types of interfaces all appear in the copper diffusion zone in the steel area. Furthermore, it was found that the copper element will be supersaturated and precipitated in the steel area, and the precipitated copper element will linearly diffuse to cause the generation of microcracks. EBSD analysis results show that forming copper on steel can obtain a wider range of fine-grained regions, and the fine-grained existence can hinder the propagation of branch microcracks.