Additive manufacturing technologies such as powder bed fusion using a laser beam (PBF-LB) have been gathering attention in the past decades as alternative manufacturing methods for the production of Ni-base superalloys. This interest stems from the high potential of these techniques for the production of near-net-shape components with highly complex geometries, not only reducing costs but also opening new possibilities for microstructural and topological optimization.

However, the use of these techniques for the production of superalloys also leads to a number of technical difficulties. Apart from presenting defects such as pores or cracks, PBF-LB superalloys are known to react differently to standard heat treatments, presenting not only a distinct microstructure but a contrasting mechanical behaviour when compared to conventional materials. In this context, this study aimed at an in-depth description of how PBF-LB affects the microstructure and micromechanical behaviour of a polycrystalline superalloy over the course of a standard heat treatment (AMS 5668), focusing on the grain dimensions and morphology, the crystallographic texture and defects, and the microhardness of the material.

When comparing these features to its wrought counterparts, difficult recrystallization and homogenization of the PBF-LB material has been evidenced, which resulted in an out-of-equilibrium development of microstructure and microhardness during the heat treatment steps.