Dislocation-induced ultra-high strength in a novel steel fabricated using laser powder-bed-fusion

In this work, a novel advanced steel (Fe–10Mn-1.6Al-0.4C-0.7V, wt.%) with excellent mechanical properties of yield strength 1076 ± 44 MPa, true ultimate tensile strength 1626 ± 58 MPa and true fracture strength 1589 ± 52 MPa is successfully fabricated by laser powder-bed-fusion (L-PBF). The contributions of solid-solution strengthening, grain-boundary strengthening and dislocation strengthening to the yield strength and true fracture strength are well investigated. The dislocation strengthening contributes to the majority of strength, which accounts for ∼44% of the yield strength and ∼59% of the true fracture strength due to the high dislocation density in the L-PBF fabricated Fe–10Mn-1.6Al-0.4C-0.7V. This study provides insight not only for understanding the strengthening mechanisms of the Fe–10Mn-1.6Al-0.4C-0.7V, but also for the future development of advanced steels with outstanding properties for L-PBF.