Tribological behaviour of 316L stainless steel additively manufactured by laser powder bed fusion and processed via high-pressure torsion

For the first time, the tribological behaviour of 316 L stainless steel (316 L SS) additively manufactured via laser powder bed fusion (L-PBF) with ultrafine- and nano-grains obtained from high-pressure torsion (HPT) processing has been investigated. The pin-on-disk dry sliding wear test results demonstrate enhancement wear performance after HPT processing, as indicated by the consistently lower coefficient of friction (COF), mass loss, m and specific wear rate, k values than the as-received state. The improvement in overall wear resistance could be attributed to the significantly high hardness obtained due to the nano-scale grain refinement with increasing torsional strains. Microscopy analysis suggests that the wear mechanism transitioned from severe abrasive wear before HPT to a combination of mild abrasive, adhesive, and tribo-oxidative wear after HPT.