Microstructural evolution induced by heat treatment in the Co28Cr6Mo alloy produced by Selective Laser Melting

Co28Cr6Mo alloy is one of the most widespread biomaterials used for the fabrication of permanent implants that nowadays can be processed by Additive Manufacturing (AM) techniques. In fact, the biomedical field takes great advantages from additive technologies, specifically Selective Laser Melting (SLM), due to the possibility of realizing tailored devices, based on the actual patience needs. Conventional processing routes of this alloy are complex and often require a heat treatment aimed at improving, for example, wear resistance. However, by considering the very fine and peculiar SLM microstructure, heat treatment parameters should be specifically optimized. The present work focused on the investigation of the effects induced by aging treatments in the microstructure of SLM Co28Cr6Mo alloy. The analyses allowed to delineate the evolution occurred in the microstructure as a consequence of thermal exposure and to identify the conditions which determine the complete modification of the as-built microstructure.