Powder bed fusion of high-Mn-N Ni-free austenitic stainless steel: achieving low porosity and high mechanical strength through process parameter selection

Abstract

The emergence of innovative high-performance stainless steels is essential at the forefront of material science. This research highlights the meticulous development of a novel high-Mn-N Ni-free austenitic stainless steel via the powder bed fusion laser–based (PBF-LB) technique. We strategically optimized the laser parameters, achieving ultralow porosity and a refined microstructure with defects under 2%. Comprehensive analysis revealed superior dendritic cellular formations at melt pool boundaries, underlining our method’s precision. Unveiling the strength of this novel steel, sample S11 (scanning speed of 800 mm/s and laser power of 147 W) showed a remarkable tensile strength of 1190 ± 20 MPa and an impressive elongation to fracture of 35 ± 3%. Interestingly, twin formations became evident under external loads, enhancing mechanical resistance while preserving ductility. Advanced quantification methods were employed to ensure accuracy, especially for low atomic number elements, overcoming previous measurement constraints. This pioneering study introduces a game-changing austenitic Ni-free stainless steel enriched by Mn and N. It sets a new benchmark in material development and application, synergizing exceptional mechanical attributes with robust ductility.