Precipitate evolution and strengthening mechanisms in L-PBF GRCop-42 under thermal aging

• Comprehensive unveiling of L-PBF processing implications on the GRCop-42 alloy microstructure. • Establishment of the solid solution evolution critical role in precipitation dynamics to design efficient post-processing pathways. • Identification of temperature–time dependent recovery mechanisms that govern microstructural performance. • Evidence that low-temperature aging is a superior strategy for ensuring long-term stability in high-temperature applications. High-performance copper alloys are increasingly sought across multiple industries, including medical, power and energy, advanced tooling, and manufacturing, due to their exceptional thermal conductivity, oxidation resistance, and mechanical strength. Among these, GRCop-42 (CuCrNb) has gained strategic importance especially in aerospace engineering, where materials must endure extreme thermal gradients and mechanical loads in high-heat-flux environments, most notably in reusable rocket propulsion and combustion chamber applications. The performance of GRCop-42 is largely controlled by a fine dispersion of Cr 2 Nb Laves phase particles, which strengthen the alloy through precipitation and dispersion-hardening mechanisms. Additive manufacturing techniques, especially Laser Powder Bed Fusion (L-PBF), offer the potential to further refine the microstructure due to their inherently rapid solidification rates. This study investigates the microstructural evolution of L-PBF processed GRCop-42, with a particular focus on the thermal stability and coarsening behaviour of Cr 2 Nb precipitates under various aging conditions. By employing advanced microscopy techniques (FESEM and TEM) alongside crystallographic analyses (XRD and EBSD), this research aims to elucidate the mechanisms of Ostwald ripening and their influence on the alloy strengthening behaviour.