Effect of Interlayer Composition on the Properties of Laser-Directed-Energy-Deposition-Based Additively Manufactured Copper-Stainless Steel Wall Structures

Abstract

Laser-directed energy deposition (LDED) is one of the advanced techniques used for the sustainable manufacturing of engineering components with minimal material wastage and higher performance. This paper reports an investigation on LDED-based additive manufacturing of compositionally graded Copper (Cu)-stainless steel (SS) wall structures for improved performance of tooling components. Three different approaches, such as Cu-SS direct joint, 20% graded Cu-SS, and 50% graded Cu-SS, are used to build the wall structures. Optical microscopy of LDED-built graded samples reveals defect-free deposition of Cu-SS direct joint and 50% graded Cu-SS wall structures at identified process parameters, whereas the 20%-graded wall yields micro-cracks in the lower Cu region. The elemental distribution shows gradual traditions in the weight percentages of Cu and Fe along the built wall. Furthermore, the ultimate tensile strengths of the direct Cu-SS joint wall structure and the 50%-graded Cu-SS wall structure are higher than the strength of LDED-deposited Cu, while the 20%-graded Cu-SS wall structure has lower ultimate tensile strength than the strength of LDED-deposited Cu. Lower ultimate strength and failure in the lower-Cu zone of 20% graded Cu-SS wall structure can be attributed to the presence of micro-cracks in the Cu20SS80 zone of 20%-graded Cu-SS wall structures. The study establishes LDED as a technique for building multi-material components promoting sustainability in terms of manufacturing and component performance.