Hybrid Additive Manufacturing of MS1-H13 Steels via Direct Metal Laser Sintering

A bimetal steel was additively manufactured by depositing maraging steel powder (MS1) on top of a hot work tool steel H13 through the direct metal laser sintering (DMLS) technique. The microstructure of the substrate-H13 and DMLS-MS1 as well as the interfacial morphology of the hybrid MS1-H13 steel were characterized using optical microscopy (OM) and scanning electron microscopy (SEM). The microhardness tests were carried out to investigate the mechanical behavior of the hybrid MS1-H13 steel. The results showed that no cracks, porosities, or discontinuities were formed at the interface proving a reliable hybrid MS1-H13 steel. In addition, the hybrid additive manufacturing process had no detrimental influence on the substrate-H13. A very sharp interface as narrow as 2 mu m was detected between the DMLS-MS1 and the substrate-H13 hot work tool steel. The microhardness tests across the interface revealed an abrupt increase of the hardness values on the printed side leading to a stronger interface.