The GH4169 superalloy samples were fabricated by selective laser melting. The effects of solution plus double aging heat treatment on the microstructures and tensile properties of selective laser melted GH4169 samples have been investigated. The microstructure of as-deposited GH4169 samples and precipitations after heat treatment were characterized. In the horizontal section (normal to the deposition direction)

the as-deposited sample occurs a fine cellular grains structure

while in the vertical section (parallel to the deposition direction)

the as-deposited microstructure shows a dendritic structure with a certain epitaxial growth feature. The precipitation of the strengthening phase is inhibited due to the fast cooling rate

thus the microstructure of as-deposited GH4169 sample is characterized by supersaturated austenite matrix γ and inter-dendritic γ + Laves eutectic. After solution plus double aging heat treatment

the dendritic grains and Laves phase dissolved in the austenite matrix. The plate-like δ phase precipitates at the grain boundary

and the discshaped γ"-Ni3Nb phase and the granular γ'-Ni3 (Al

Ti) phase are dispersed inside the grains. The tensile strength of the asdeposited sample are improved after heat treatment. Under the effect of precipitation strengthening

the tensile properties of the heat-treated GH4169 sample at room temperature are comparable to those of forgings.