Evaluation of wear mechanism between TC4 titanium alloys and self-lubricating fabrics

Abstract

Self-lubricating spherical plain bearings are important product components in the aerospace industry. With technological advances, the limitations of steel self-lubricating spherical plain bearings with high quality but poor corrosion resistance became quite evident. The preparation of self-lubricating spherical plain bearings made of titanium alloys is of great interest. In general, titanium alloys have poor tribological properties as well as unsatisfactory tribological performance when they rub with soft self-lubricating fabrics. To understand the wear mechanism of TC4 titanium alloys, half-ring wear tests were conducted between TC4 titanium alloys and self-lubricating fabrics under different pressures and swing frequencies, namely, 50 and 100 MPa, and 0.2 and 0.4 Hz, respectively. The corresponding results showed that the friction coefficients (COFs) between TC4 titanium alloys and self-lubricating fabrics greatly fluctuated in the range of 0.1–0.25. The main wear form of titanium alloys was a combination of abrasive wear and adhesive wear, and the accumulated debris generated during the friction process was the main cause of surface damage of TC4 titanium alloys. The accumulated debris tended to increase with increasing pressure and swing frequency. The debris scratched and made large grooves in titanium alloy surfaces and aggravated the wear of self-lubricating fabrics, which led to severe fibre breakage. This paper describes a novel wear mechanism of accumulated debris and offers a solid theoretical foundation for the application of titanium alloys in the field of self-lubricating spherical plain bearings.