GH4169 alloy samples were manufactured by selective laser melting (SLM). The microstructure evolution and stress rupture properties of samples during hot isostatic pressing (HIP) and heat treatment (HT) process were analyzed by OM

SEM

EBSD and TEM. The results show that most of grains of the as-built samples are elongated in the building direction

exhibiting a very fine cellular-dendritic structure with fine Laves phase precipitating in the interdendritic region. Most of porosities and Laves precipitates disappear after HIP

and the microstructure parallel to the building direction is transformed into equiaxed grains. Besides

the HIP treatment can significantly lower the precipitation of needle-like δ phase in the grain during the subsequent solution treatment at 980℃ for 1 hour. The HIP treatment can improve the stress rupture lifetime

but decrease the elongation slightly..