from the conferences organized by TANGER Ltd.
Superalloys based on Ni, Ni-Fe, and Co are among the most used metallic materials for high-temperature applications due to their excellent strength, creep and corrosion resistance. Co-based superalloys, in particular, offer superior corrosion resistance compared to Ni-based counterparts, making them ideal for long-lasting components subjected to moderate static or cyclic loads at elevated temperatures. However, their high hardness and strength pose significant challenges in machining, increasing production costs. To overcome these limitations, research has increasingly focused on additive manufacturing techniques that enable the fabrication of complex geometries with reduced material waste. This study investigates the feasibility of producing the Co-based superalloy Mar-M-509A using laser beam powder bed fusion (LB-PBF) followed by post-processing heat treatment. Components fabricated by laser powder bed fusion (LB-PBF) typically exhibit inherent internal porosity, microstructural anisotropy, and elevated residual stresses due to the rapid solidification and layer-wise nature of the process. These deficiencies necessitate the application of post-processing techniques, such as heat treatment or hot isostatic pressing (HIP), to enhance the microstructural integrity and mechanical performance of the material. This study examines the influence of various LB-PBF process parameters on the relative density of printed components and evaluates the effects of heat treatment and HIP on the microstructure and tensile properties. Heat treatment aimed at relieving internal stresses resulted in a yield strength of up to 980 MPa with an elongation of 6.5 %. In contrast, HIP treatment led to a reduction in yield strength to 730 MPa but significantly improved elongation to 9.9 %. The microstructural evolution induced by HIP and its impact on mechanical performance are analysed and discussed in detail.
Keywords: Powder bed fusion, heat treatment, hot isostatic pressing, tensile strength© This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.