Investigation on wear behavior of cryogenically treated Ti-6Al-4V titanium alloy under dry and wet conditions

Abstract

Titanium alloys are widely used in many fields because of their excellent comprehensive properties. However, its poor friction and wear properties limit its many potential applications. In general, the surface roughness of important parts manufactured by titanium alloy should meet certain requirements. As a low-cost and high-efficiency processing method, barrel finishing has been used for the surface finishing of titanium alloys. The main material removal mechanism of barrel finishing is micro-cutting/grinding, which is similar to the material wear mechanism under some conditions. In addition, titanium alloys are subjected to a low force in common surface finishing processes. Cryogenic treatment is a method that can improve the comprehensive properties of titanium alloys. Therefore, the friction and wear behavior of cryogenically treated Ti-6Al-4V titanium alloy (CT Ti alloy) and non-cryogenically treated Ti-6Al-4V titanium alloy (NT Ti alloy) at a low load and scratch speed was studied comparatively in this paper. The results show that the CT Ti alloy exhibits a lower friction coefficient and wear rate under both dry and wet wear conditions. Under wet conditions, the stabilized friction coefficient is lower than that under dry conditions. The stabilized friction coefficient of CT Ti alloy is 0.18 after reaching a stable wear stage under wet conditions. Under dry wear conditions, the NT Ti alloy mainly showed typical abrasive wear, heavy adhesion wear and oxidation wear characters. The wear mechanisms of CT Ti alloy are mainly abrasive wear, slight adhesion wear and oxidation wear. Under wet wear conditions, the wear mechanism of NT Ti alloy is abrasive wear and slight adhesion wear. After cryogenic treatment, the mechanism for CT Ti alloy is slight abrasive wear.