Improving tribological properties of TC4 strengthened by tungsten using ESA

Abstract

ABSTRACT In this paper, TC4 titanium alloy surfaces were strengthened by electro-spark alloying (ESA) with the tungsten rod as an electrode to investigate the effects of voltage and pulse frequency on tribological properties of tungsten-strengthened layers. It was shown that the surface morphology of strengthened TC4 possesses a main tungsten phase with a typical characteristic of sputtering. The maximum average thickness and microhardness of strengthened layers had been achieved at 50 μm and 21.6 GPa, respectively. The latter had been found to be 6–7 folds higher as opposed to that of TC4. In the friction tests conducted, the friction coefficient and wear loss of strengthened layers appeared to be reduced by approximately 76.2% from 0.45 to0.11, as well as 89.47% from 3.8 to 0.4 mg accordingly. Overall, this study offers an effective preparation method of wear-resistant tungsten-strengthened layers with the resulting low friction coefficient on TC4 surfaces via ESA.