Parametric study and characterization of AlN-Ni-Ti6Al4V composite cladding on titanium alloy

Titanium and its alloys have wide applications in the field of aerospace as well as medical. But their poor surface properties (i.e. low hardness and wear resistance) restrict the uses in the harsh working environment. To address this drawback, a composite cladding of aluminum nitride (AlN), Nickel (Ni) and Ti6Al4V powders was formed on the Ti6Al4V plate. Three process parameters namely, laser power, scanning speed and percentage composition of AlN in the powder mixture were considered to study their influence for obtaining required hardness and layer thickness of the cladded surface. Further, characterization of clad layer morphology, micro-hardness in the subsurface layer, wear behavior of the cladded surface and elemental compound formations were carried out. The experiment investigation revealed that the micro-hardness of the cladded surface is in the range of 1000-1250 HV0.54kg which is approximately three times of the parent material. Also, very few pores and cracks were noticed on the cladded surface. It was observed that fine-grain columnar structure forms dendrite which enhances mechanical properties of the cladded surface. XRD result shows the good affinity between substrate material and powders and the formation of intermetallic compounds like TiN, Ni3Ti, and Ti3AlN which improve the micro-hardness properties of the cladded layer.