Experimental study on characteristics of laser metal deposited Al-Si-Sn-Cu/Ti-6Al-4V composite coatings

The development of laser based advanced coatings are continually implemented in order to meet the desired demands and performances of materials in industries. Many engineering materials used in industrial conditions are subjected to corrosion, wear and fatigue attack leading to rapid degradation of the material. This research is aimed at fabricating Al-Si-Sn-Cu quaternary coatings on Ti-6Al-4V alloy. A 3-kW continuous wave ytterbium laser system (YLS) attached to a KUKA robot which controls the movement of the cladding process was used for the laser cladding process. The appropriate selection of laser processing parameter produced desirable result and properties. Enhanced surface hardness and tribological properties were achieved as a result of well optimized laser process parameters and appropriate selection of reinforced powders. The results of the microhardness revealed an improvement as the hardness measured for the cladded Al-Si-Sn-Cu layer was 602 HV0.1. While the micro-hardness of the Ti-6Al-4V substrate was 302 HV0.1. Also, the COF of Al- Si-Sn-Cu quaternary coatings are lower than that of the Ti-6Al-4V substrate, which was attributed to strengthening effect and higher load bearing aptitude of Ti3Al, CuTi2, AlSi3Ti2, SiTi, AlTi0.6V0.4, and Al0.25Sn0.75V3 hard phases present in the coatings. The protective intermetallic phases result to a reduction in coefficient of friction and therefore demonstrated superior wear resistance performance.