Additive manufacturing processes are now widely studied for numerous applications in the nuclear industry. The aim of the studies dedicated to optimising the Laser Metal Deposition (LMD) metal additive manufacturing process for the production and shaping of a 13-4 martensitic stainless steel is to obtain a material with mechanical properties at fracture, particularly in terms of impact strength, that comply with the specifications for use. This work explores the complex relationships between the microstructural characteristics (phase present, granular structure, texture, precipitation, etc.) induced by the process and the resulting mechanical performance.
Additive manufacturing, in particular the LMD process, offers multiple advantages in terms of design flexibility and customisation of metal components. However, obtaining mechanical properties at fracture that meet specifications is a major challenge, particularly for high-temperature applications in corrosive environments.
This thesis focuses on the optimisation of the LMD process to ensure that components manufactured from 13-4 martensitic stainless steel exhibit microstructural characteristics and mechanical performance appropriate to their intended applications, with particular emphasis on impact properties. Determining the optimum process parameters, including the characteristics of the powders and associated post-treatments, the analysis of the microstructure, and the correlation between the microstructure and the mechanical properties constitute a major challenge for the complete control of this process.