Effect of coating thickness on microstructural and mechanical properties of titanium coated aluminum alloy deposited by vacuum arc melting method

Abstract

This study aims to investigate the effects of titanium coatings on aluminum alloy’s tribological and fatigue properties. In this investigation, aluminum alloy samples were coated with 1 μm, 3 μm, and 5 μm using the vacuum arc melting method. The morphological and mechanical features of the samples were characterized with SEM, microhardness, contact nanoprofilometer, and calotest methods. The increase in coating thickness resulted in improved adhesion properties and achieved better surface hardness. Further, hard sub-surface layers on the aluminum alloy substrate increased fatigue resistance. The superior mechanical properties, such as microhardness, lower surface roughness, and good bonding at the interface, are critical factors in increasing the fatigue and wear resistance of the aluminum alloy. No traces of defects, such as microcracks and porosity, were found on the coated samples. The microhardness of the coated sample increased by 3.69 times that of the AK5M2 aluminum alloy. The fatigue lifetime of the 5 μm coated samples was increased by 21%. The wear resistance of titanium-coated samples showed better wear resistance against the steel counter body than other coated and uncoated samples.