Effects of Silicon Carbide (SiC) Reinforcement on the Microstructure and Mechanical Properties of Laser Deposited Al-Sn-SiC/Ti-6Al-4V Composite Coatings

Abstract

Titanium and titanium alloys have a large array applications attributed to its low density, good corrosion resistance and high specific strength. Damage to the surface can be improved by surface modification for extended application. Direct laser metal deposition (DLMD) technique can be used to address the limitations associated with titanium alloy. This is mostly achieved by integration of reinforcement materials into the main matrix to form coating. Thereby inducing microstructural changes to the material. The morphology and also the hardness property of the various composite coatings were examined. The hardness of the composite coating was found to range between 450.64 and 638.22 HV, and the hardness obtained for 10% SiC reinforcement coating was 638.22 HV. For all the coatings, the hardness was established to be much higher than that of the substrate, which was averaged 304.21 HV. Hardness value increases with increase in SiC content. The enhanced hardness values were due to refined grains and intermetallics in the microstructure of the coatings. Moreover, the highest tensile and yield strengths was found at 10 wt.% SiC due to the uniform particle dispersion that can impede dislocation movement. The uniform distribution of SiC particles in the Al-Sn matrix had a good effect on its mechanical properties.