A study of parametric optimization, microstructure and wear behavior of an AA7075–SiC composite coating developed by friction surfacing

Abstract

This research work was performed to successfully develop a wear-resistant AA7075–SiC composite coating over AA6082 substrate via friction surfacing. For the composite coating deposition, AA7075 consumable rod with micron-sized SiC reinforcement particles filled in the blind holes on its end was considered. The critical process parameters, such as rotational speed (RS) (1000, 1200, and 1400 rpm), number of holes (1, 2, and 3 holes) containing reinforcement and transverse speed (TS) (140, 160, and 180 mm/min) were investigated to determine their influence on the output responses such as microhardness, bond strength and dry sliding wear of the composite coatings. The experiments were planned as per Taguchi’s L9 orthogonal array, and the process parameters were multi-optimized using grey relational analysis. The optimized composite coating developed at a RS of 1200 rpm, TS of 140 mm/min, and three holes exhibited a bond strength of 154.72 MPa, improvement in the hardness by 108.7% and reduction in the wear by 56.02% as compared to the substrate. The noteworthy grain refinement in the coating occurred after the addition of SiC microparticles due to the Zener pinning effect. The worn surfaces of the coatings indicated the abrasion and adhesion wear mechanism during the wear testing.