Combined Effect of Cryogenic and Aging treatments on Wear Behavior of Ti-6Al-4V α/β Alloy for Biomedical Applications

Abstract

Ti-6Al-4V α/β titanium alloy is used in biomedical applications to produce artificial joints due to its excellent osseointegration property, high corrosion resistance, low density, and low Elasticity modulus compatible with bone structure. Considering the usage area, Ti-6Al-4V alloy is expected to have high tensile properties and high wear resistance. In this study, aging treatment and a combination of aging and cryogenic treatment were applied to the alloy to obtain high tensile properties and wear resistance. Cryogenic treatment was conducted at deep (-196°C) and shallow (-140°C) cryogenic treatment temperatures. Also, aging treatment was conducted to the alloy with/without cryogenic treatment as a single-step or duplex. The effect of the heat treatment types on the alloy's mechanical and microstructural properties was determined by tensile test, hardness test, wear test, XRD phase analysis, and microstructural investigations. With the application of the duplex aging treatment amount of the β phases decreased, a good balance between tensile strength and the elongation was obtained, and the wear resistance of the alloy increased compared to the single-step aging. In addition, the decrease of the cryogenic treatment temperature slowed down the phase transformation kinetics and caused a decrease in precipitation of α phases at both single-step and duplex aged samples. Superior wear resistance was obtained with the reduction of β phases in the microstructure of the samples that were duplex aged after cryogenic treatment.