Fabrication of structural and compositional heterostructured CoCrNi–CoCrFeMnNi multi-material using direct energy deposition additive manufacturing

Abstract

Metal additive manufacturing (MAM) is an emerging processing technology that can efficiently produce various metallic materials. Aimed at controlling material properties to suit functional requirements, there has been a considerable demand in recent years to manufacture multi-materials with locally different chemical compositions from one material composition to another. However, due to the technical difficulties of MAM, MAM-processed multi-materials have a fundamental limitation of high defect probability near the interface. In this study, to overcome the limitations of MAM-processed multi-materials, we proposed a new strategy for multi-material fabrication by depositing a single layer of CoCrFeMnNi high-entropy alloy (HEA) on a cold-rolled CoCrNi medium-entropy alloy (MEA) substrate using direct energy deposition. The prepared CoCrNi–CoCrFeMnNi multi-material exhibits both structural and compositional heterogeneity, and no defects were observed. In addition, it has a superior strength-ductility combination compared to the individual properties of homogeneous CoCrNi MEA and CoCrFeMnNi HEA owing to a synergetic strengthening effect with the heterogeneous microstructure.