High cycle fatigue behaviour of Ti-6Al-4V fabricated by metal injection moulding technology

Titanium alloys exhibit an excellent combination of properties, including high specific strength and excellent bio-compatibility. Recently, parts made from titanium alloys such as Ti-6Al-4V have been manufactured by metal injection moulding (MIM) and exhibited excellent tensile properties (UTS > 800 MPa and ɛ > 15%). However to date, few information concerning the fatigue properties of such material has been presented in the literature. Thus, in the present study, the influence on the high cycle four-point bending fatigue behaviour of Ti-6Al-4V alloy processed by standard and MIM techniques was examined. The first results indicated that the fatigue strength of components fabricated by MIM technique is significant lower than parts made by standard process. This behaviour is discussed in terms of mechanical properties, microstructure, composition, surface quality and crack initiation mechanisms.