Abstract
A ferritic stainless steel with ultra-high strength and maintaining certain ductility was successfully prepared by selective laser melting, using UNS S32750 duplex stainless steel spherical powder with a particle size of 15-53 μm prepared by electrode induction-melting gas atomization. The microstructure, mechanical properties, and corrosion resistance of the duplex stainless steels before and after solution treatment were studied. The results indicate that, the microhardness, tensile strength, yield strength, elongation, and impact absorption energy of the as printed samples are 449 HV, 1475 MPa, 1265 MPa, 11.6% and 25.99 J, respectively. After solution treatment at 1150℃, the areas of α phase and γ phase are 55.2% and 44.8% respectively, with a ratio of approximately 1:1. The microhardness, tensile strength, yield strength, elongation, and impact absorption energy are 329 HV, 913 MPa, 601 MPa, 34% and 231.82 J, respectively. The strength and microhardness of stainless steel decreased, while its plasticity and toughness were enhanced. The self corrosion potential and pitting potential are higher than those of the printed sample, but the self corrosion current density is lower than that of the printed sample.
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