Fatigue Crack Initiation in a Two Phase B-Metastable Titanium Alloy: Influence of Microstructural Parameters

A new generation of α/β titanium alloys with enhanced performance over density ratio is currently receiving lots of attention from the aerospace industry. One of the critical parameter is the fatigue resistance in the both low and high cycle fatigue (LCF and HCF) regimes, in particular the crack initiation. Fatigue initiation is strongly influenced by several characteristics of the microstructure such as grain size, grain orientation and misorientation (e.g Jin et al. [1]). Up to now, the initiation of fatigue cracks in the new low cost beta (LCB Ti alloys) has been characterised only in the case of a fully β microstructure (Hu et al. [2], Krupp et al. [3], Floer et al. [4]). Furthermore, hardly anything can be found in the literature on the fatigue crack initiation in multiphase Ti-based microstructures.