One drawback of the laser powder-bed fusion additive manufacturing (AM) technique is the build-up of residual stresses during processing that require a stress-relief heat treatment prior to components being removed from the build plate. Here, we demonstrate the coprecipitation of the gamma-double-prime-phase alongside the known delta-phase, during stress-relief annealing of AM Inconel 625 at 870 °C. The unexpected precipitation of gamma-double-prime in the AM material is attributed to the local solute enrichment to the interdendritic regions of the as-built solidification microstructure. Dissolution of the delta and gamma-double-prime phases is achieved after annealing for 15 min at 1150 °C.
Additive manufacturing, Ni-based alloys, Inconel 625