Grain boundary behaviour and impact fractography of cryogenic treated AISI 316l manufactured by laser powder bed fusion.

• AISI 316L developed by LPBF process was subjected to heat and cryogenic treatments. • The crystal lattice structure is more orderly after cryogenic treatments. • Increased deformation of twins is observed after heat and cryogenic treatment. • Cryogenic treatment relieves internal residual stresses developed during printing. • Grain refinement occurs after the heat and cryogenic treatments. AISI 316L manufactured using laser powder bed fusion process was subjected to heat and cryogenic treatments. The effect of microstructural and mechanical properties, such as hardness, thermal residual stress, and Charpy impact, were investigated. The results indicate that after the heat and cryogenic treatment, the amount of austenite (FCC) phase increased, and the residual stress was removed after the heat and cryogenic treatment. The increase in deformation twins (Σ3) was observed after heat and cryogenic treatment. The cryogenic treatment altered the crystal lattice and orientation of crystal grains, resulting in grain refinement. [ABSTRACT FROM AUTHOR]