High Stress Wear Behavior of Ti-6A1-4V with Surface Modification by Electro-Spark Alloying

Titanium has long been recognized as a troublesome material in situations dominated by sliding (or rubbing) contact, exhibiting poor wear resistance in high contact stress situations. Considerable effort has been directed toward modifying the surface of titanium (and its alloys) for the purpose of reducing wear. This study examines the wear reduction possibilities of various surface coatings on a titanium alloy by the electrospark alloying process. ESA, best defined as microwelding process, uses a short duration pulsed arc to alloy an electrode material (often a carbide) with substrate. High stress sliding wear conditions were created using a standard crossed cylinder friction and wear machine per ASTM G- 83. Tests using hardened 4340 steel, and sintered tungsten carbide as the stationary member and the ESA coated titanium as the rotating member were conducted. Weight loss results from the crossed cylinder tests, established that all the coatings were highly effective in preventing sliding wear.