Aluminum alloys meet a requirement of light weight vehicles and structural materials, however it is some problems to practical application concerning with the less wear resistance. Many attempts were tried to overcome this poor resistance characteristics using fusion processes including welding laser and plasma processes. However, these fusion processes suffered from defects as porosity and as cracks in the surface modified zone. The friction coating is one of the solid-phase processes with the inherent features including negligible dilution of substrates, no porous defects, a narrower HAZ dimensions as well as the advantage of faster deposition rates. Here, it will deals the novel process concerning with surface modification using friction. An unique application is called friction thermomechanical process (hereafter referred as FTMP) for surface modification of aluminum alloys casts. In this process, a non-consumable rod is forced to contact with the substrate while rotating which was given a hint from observing friction coating process. The friction heat, generated at the interface between the rod and substrate, makes substrate metal plasticized. The coarse cast microstructures on the substrate surface have been continuously refined due to dynamic recrystallization. As a result, surface modification can be performed by FTMP, where the zone within 3 mm depth from surface can be treated with hardness increment and refined microstructures and be disappeared cast defects.
