Integrated Experimental Approach for Alloying of Surface Layer Ti6Al4V+B4C Metal Matrix Composites using Laser Treatment

Abstract

Surface engineering applications have brought the titanium and its alloys into the limelight in the manufacturing industries such as the aerospace, automobile, marine, chemical processing industry, nuclear power and biomedical. Despite the growths experienced in the use of this material, it is plagued with poor wear behaviour, especially when in contact with other materials during application. In this research work, the reinforcement of titanium alloy (Ti6Al4V) and boron carbide (B4C) ceramic powders was employed to form the Ti6Al4V+B4C composites. The effect of laser power on the micrograph, microhardness, surface roughness and wear has been investigated. The micrographic evaluation, the geometrical analyses and the effect of laser power on the width and height of deposit, aspect ratio and dilution rate were also evaluated. The highest aspect ratio of 5.31 and dilution rate of 63.81 % was observed in sample MB5 deposited with a laser power of 2400 W. The dry sliding friction and wear conducted using a 10 mm diameter tungsten carbide ball and a normal load of 25 N revealed that sample MB2 produced at a laser power of 1800 W has the lowest wear depth and wear width of 74.6 µm and 1080.77 µm. From the lowest COF attributed by sample MB5, it can be inferred that coefficient of friction does not determine the wear loss due to the sticking of some wear debris to the wear track during sliding action. Thus, other wearing factors are also considered for the wear loss evaluation. However, this composite can be used for the repair of the worm part of a rotating shaft and turbine blades.

Keywords

• AFM surface morphology
• boron-carbide
• dry sliding wear
• metal matrix composites
• micrograph
• microhardness
• Ti6Al4V alloy