Towards the design of dynamically loaded titanium engineering components

Abstract

Surface engineering research centred at the University of Birmingham has, for several years, been directed at producing wear-resistant surfaces on titanium alloy substrates in order to facilitate the use of titanium alloys in general engineering applications, usually as direct replacements for steel components. More specifically, bearings and gears have been identified as an area in which this could be accomplished, where a low coefficient of friction, low wear rate and load-bearing capacity are all necessary. The processes investigated have included plasma nitriding, physical vapour deposition, laser surface alloying and electron beam surface alloying and currently ion implantation and plasma immersion ion implantation. Some results from plasma nitriding and energy beam surface alloying processing and evaluation achieved to date are included which have culminated in the use of a duplex surface engineering process. This process has allowed a Ti6Al4V alloy (where the compositions is in approximate weight percent) to be tested at 1300 MPa maximum hertzian contact pressure and 50% slip. This represents an improvement of 1200% in contact pressure and 500% in slip ratio survival over untreated Ti6Al4V.