Crossing the limits of 316L steel fabricated by powder bed fusion by thermomechanical post-processing

• Performance of additively manufactured steel enhanced by tailored post-processing via rotary swaging. • Hot and cryogenic swaging refined grains and introduced (various levels) of substructure. • Swaging increased corrosion resistance and mechanical properties of 3D printed steel. • Cryo swaged sample exhibited enhanced pitting potential due to formation of {111}||SD texture. Methods of laser powder bed fusion (LPBF) are popular although LPBF components feature issues negatively affecting their mechanical properties and corrosion behaviour. Post-processing of LPBF materials by deformation treatments can reduce/eliminate printing defects and enhance their performance. The study examines the effects of post-processing of LPBF AISI 316L steel workpieces, performed by the intensive plastic deformation method of rotary swaging, on the microstructures, mechanical properties, and corrosion behaviour. The results showed that the applied post-processing introduced grain refinement (cryogenic swaging to the ultra-fine scale) and grain size homogenization, as well as generally enhanced the resistance against corrosion and increased Vickers microhardness of the LPBF steel. The increased corrosion resistance of the cryo swaged sample was, most probably, primarily caused by the formation of {111}<110> shear fibre texture, while for the hot swaged sample, the increased corrosion resistance could primarily be attributed to the recrystallized microstructure. Hot compression testing revealed that the hot swaged sample featured higher activation energy for recrystallization than the cryo swaged one. On the other hand, the energy accumulated within the ultra-fine grained cryo swaged sample, due to aggravated plastic flow during processing, promoted the development of dynamic recrystallization during the hot compression testing.