Effects of heat treatment on the microstructure and mechanical properties of GH3536 superalloy fabricated by electron beam powder bed fusion

This study systematically evaluated the influence of solution treatment (ST) on the microstructure and corresponding mechanical properties of GH3536 superalloy fabricated by electron beam powder bed fusion (EB-PBF). The as-deposited (AD) GH3536 superalloy exhibits preferentially oriented columnar grains with continuous chain-like carbides distributed at the grain boundaries. The ultimate tensile strength (UTS) of the AD sample is 535.1 MPa, with an elongation of 17.0%. After ST, the epitaxially grown columnar grains are gradually replaced by equiaxed grains, and the chain-like carbides are re-precipitated in a granular and dispersed distribution. Mechanical property tests indicate that at a solution temperature of 1100°C, the GH3536 superalloy exhibited an optimal combination of strength and ductility, achieving a tensile strength of 583.5 MPa and an elongation of 48%. Fracture morphology analysis reveals that the fracture mode of the AD samples shows a mixed ductile-brittle fracture, whereas after ST, it transforms into a microporous aggregation-type ductile fracture. This study provides a theoretical basis for optimizing the mechanical properties of GH3536 alloy fabricated by EB-PBF.