Effect of laser cladding process parameters on clad quality and in-situ formed microstructure of Fe-TiC composite coatings

Over the past decade, researchers have demonstrated interest in tribology and prototyping by the laser cladding process. In-situ laser cladding enables the formation of a uniform clad by melting the powder to form desired composition from pure powder component. In this research pure Ti, graphite, and Fe with max particle sizes of 40 mu m (0.04 mm) are used for in-situ laser cladding on a steel substrate. The effects of laser parameters on the quality of an in-situ formed TiC-Fe based composite clad are investigated. Laser parameters have an important role in clad quality and crack formation. They affect the bonding between clad/substrate and cooling rate. Diverse microstructures have been detected in the clad. Finally a model is developed in order to explain the formation and morphology of TiC. The melting and solidification stages of TiC formation and matrix confirm the suggested model. TiC particles increase the clad hardness to an average of four times greater than substrate's hardness. Experimental methods such as, XRD and SEM are used for phases characterization. (C) 2010 Elsevier B.V. All rights reserved.