Effects of the solution and first aging treatment applied to as-built and post-HIP CM247 produced via laser powder bed fusion (LPBF)

This work focuses on the production of CM247LC, a low weldable Ni-Based alloy, using selective laser melting (SLM). Despite initial process parameter optimization, the low defect volume fraction did not meet manufacturing standards, primarily due to the high γ’ volume fraction affecting weldability. However, a crack-free condition was achieved through a γ’-sub-solvus Hot Isostatic Pressing Cycle (HIP), reducing defects to 0.04% and stabilizing the microstructure. Further optimization of the microstructure is needed post-HIP. The paper discusses a new heat treatment recipe to enhance creep and high-temperature fatigue resistance by promoting ordered cuboidal primary γ’ precipitation. This treatment also significantly alters the crystalline structures, leading to grain coarsening and the formation of equiaxial grains.