Additive manufacturing of maraging steel-H13 bimetals using laser powder bed fusion technique

In this paper, maraging steel powder was deposited on top of an H13 tool steel using laser powder bed fusion (LPBF) technique. The mechanical properties, microstructure, and interfacial characteristics of the additively manufactured MS1-H13 bimetals were investigated using different mechanical and microstructural techniques. Several uniaxial tensile tests and micro-hardness indentations were performed to identify the mechanical properties of the additively manufactured bimetal. Advanced electron microscopy techniques including electron backscatter diffraction and transmission electron microscopy were used to identify the mechanism of interface formation. In addition, the microstructure of the additively manufactured maraging steel along with the conventionally fabricated substrate-H13 were studied. It was concluded that, a very narrow interface was formed between the additively manufactured maraging steel and the conventional H13 without forming cracks or discontinuities. The first deposited layers possessed the highest hardness due to grain size refinement, solid solution strengthening, and cellular solidification structure. Finally, under uniaxial tensile loading, the additively manufactured bimetal steel failed from the underlying tool steel, indicating a robust interface.