Laser additively manufactured intensive dual-phase steels and their microstructures, properties and corrosion resistance

By applying self-made intensive dual-phase steel alloy (IDP) powders for repairing various substrate materials, laser additive manufacturing (LAM) test was conducted on the surface of 2205 dual-phase stainless steels to evaluate performance of the laser additively manufactured IDP layers. The microstructure, microhardness, tensile strength and electrochemical corrosion resistance of the laser additively manufactured IDP were investigated. The results showed that the microstructure of cladding layer of the IDP powders was characterized by ferrite and austenite phases. Owing to the IDP powders contained a high Ni (nickel) content, Fe3Ni2 phase was generated in the cladding layer; the microhardness of the cladding layer was improved by about 15% compared with that of the substrate: the average microhardness of the IDP claddings was about 328 HV; the tensile strength of the IDP cladding layer was about 900 MPa, which was larger than that (750 MPa) of BM. The corrosion resistance of IDP claddings declined to some extent compared with that of 2205 dual-phase stainless steel BM. At last, bonding strengths between the laser additively manufactured IDP layer and various substrate materials (i.e. SAF2205, SAF2507, S32550 and 022Cr17Ni12Mo2) were evaluated by a series of tensile tests in vertical directions, and the bonding strengths were satisfactory. (C) 2020 The Authors. Published by Elsevier Ltd.