Wire-arc directed energy deposition of monolithic and bimetallic structures of maraging 250 steel

Metal additive manufacturing is rapidly growing as a new paradigm in on-demand customised production, where high-performance bimetallic structures demand increasingly high-performance materials such as maraging steel grade 250 (M250). The behaviour of advanced materials in additively manufactured systems requires comprehensive understanding before it is possible to move beyond their use in simplistic monolithic designs. This study demonstrates the use of M250 in radial bimetallic near-net representative structures based on a comprehensive study of M250 in wire-arc additive depositions. Monolithic structures are first produced with minimal defects, confirmed by X-ray imaging. Phase, microstructure, and tensile properties are compared for heat-treated specimens and as-processed counterparts. EBSD and Charpy impact testing is performed, fracture morphology is compared, and microhardness is determined. Representative radial bimetallic structures are produced and similarly investigated, revealing anticipated microstructure. Our results demonstrate that a comprehensive understanding of advanced additive materials allows complete design flexibility.