Laser Metal Deposition of Functionally Gradient Materials from Elemental Copper and Nickel Powders

This work deals with the planning and fabrication of a functionally gradient coppernickel composition via Laser Metal Deposition (LMD). Various compositions of copper and nickel were made by blending different weight percentages which were then sequentially deposited to fabricate functionally gradient copper-nickel thin-wall structures. Analyses were performed by sectioning the thin-wall samples for metallographic, hardness, X-ray diffraction (XRD) and Energy Dispersive X-ray Spectroscopy (EDS) studies. The fabrication was studied for identifying and corroborating the deposited compositions and their corresponding gradients. XRD analyses were performed to identify the crystal structure of the deposit. EDS analysis was instrumental in identifying the variation in composition and realizing the gradient in between compositions. Consequences of using different laser beam intensity profiles and varying laser power duty cycles were realized by analyzing the copper-nickel concentration trends obtained from EDS analyses. Hardness testing was successful in capturing the decreasing trends in strength with decreasing nickel concentration.