Laser Directed Energy Deposition based Additive Manufacturing of Copper: Process Development and Material Characterizations

This paper reports a systematic investigation on the Laser Directed Energy Deposition (LDED) based additivemanufacturing of bulk Cu structures; and microstructural and mechanical characterisation of these structures.Full factorial experiments are carried out by varying LDED process parameters for track deposition, and processwindow is identified in terms of Laser Energy per unit Powder Feed (LEPF). Further, the bulk deposition iscarried out using three inter-layer processing schemes, like - constant LEPF, decreasing LEPF, and increasingLEPF in successive layers during deposition. Cu block deposited using increasing LEPF scheme yields relativedensity around 99.9% and X-ray diffraction reveals pure Cu phase with fine crystallites. Microstructural analysisshows the dominance of equiaxed grains, with an average size of 24.47 μm. Further, an average microhardness of77 HV0.98 N, yield strength of 135 – 152 MPa and ultimate tensile strength (UTS) of 277 – 288 MPa are obtainedfor the deposited bulk Cu structures. The obtained UTS value is higher than the strength values available in theliterature for wrought, laser powder bed fusion and LDED built Cu samples. The present study paves a methodology towards the successful deployment of the LDED process for the potential fabrication of Cu componentsand parts.