Coincident wire and powder deposition by laser to form compositionally graded material

In this paper a new surface coating technique is reported. The method combines powder and wire feed laser cladding to produce a functionally graded material in a single pass. The technique is demonstrated and material distributions in the clads are investigated using H13 tool steel as a substrate, copper powder and nickel wire as feedstock and a 1.5 kW diode laser as a power source. Electron probe microanalysis, scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction and optical microscopy were used to analyse deposited clads in terms of elemental composition, microstructure and flow characteristics in the deposition melt pool. It was found that by varying the feed rates of copper powder and nickel wire, the composition gradients within a layer and overall clad properties could be controlled, avoiding the need for multipass techniques. (C) 2007 Elsevier B.V. All rights reserved.