Surface modification of Ti–6Al–4V alloy using metal arc heat source

Abstract

The surface alloying of materials such as Ti–6Al–4V is necessary to improve their wear resistance for use in tribological applications. Conventional nitriding techniques involve long processing times and the latest technology of laser processing, although widely used, is expensive. In this preliminary study, it is shown that a tungsten metal arc heat source is capable of accurate surface melting to a depth of 2 Inm and more and, when used in a controlled atmosphere of pure nitrogen or a mixture of nitrogen and argon, can produce a wear resistant surface alloy. The use of standard microhardness techniques together with wear assessment methods shows superior wear behaviour over the untreated titanium alloy. Metallographic and X-ray diffraction techniques suggest that this is a result of the formation of TiN in the resolidified region.