Microstructure and wear characterization of AA2124/4wt.%B₄C nano-composite coating on Ti−6Al−4V alloy using friction surfacing

This work is focused on developing AA2124/4wt.%B₄C nano-composite coatings on Ti−6Al−4V using friction surfacing to improve the wear resistance. The composite was produced using conventional stir casting method and coatings were laid using an indigenously-developed friction surfacing machine. The rotational speed of the mechtrode was varied. The microstructure of the composite coating was observed using conventional and advanced microscopic techniques. The sliding wear behavior was evaluated using a pin-on-disc apparatus. The coating geometry (thickness and width) increased with increased rotational speed. The interface was straight without thick intermetallic layer. Homogenous distribution of nano B₄C particles and extremely fine grains was observed in the composite coating. The interfacial bonding between the aluminum matrix and B₄C particles was excellent. The composite coating improved the wear resistance of the titanium alloy substrate due to the reduction in effective contact area, lower coefficient of friction and excellent interfacial bonding.