Low cycle fatigue crack initiation in Ti-5Al-5Mo-5V-3Cr in relation to local crystallographic orientations

A. Helstroffer (1) , S. Hémery (1) , S. Andrieu (2) , P. Villechaise (1)

1 ENDO - ENDOmmagement et durabilité [Institut Pprime]
2 SAFRAN Group

Low cycle fatigue crack initiation was investigated in a Ti-5Al-5Mo-5V-3Cr alloy with a bimodal microstructure. In particular, the crystallographic orientations of both α and β phases at crack initiation sites were characterized. Crack formation is shown to generally proceed along prismatic slip bands in primary α grains. A key role of the interplay between elastic and plastic anisotropies of both α and β phases was evidenced as the crystallographic orientation of the surrounding β matrix is a critical parameter as well. Different lengthscales have thus to be considered for an accurate prediction of fatigue crack initiation in near-β titanium alloys.

Mots clés: Ti alloy; fatigue; slip; crack initiation; crystallographic orientations

Domaines: Chimie

A. Helstroffer, S. Hémery, S. Andrieu, P. Villechaise. Low cycle fatigue crack initiation in Ti-5Al-5Mo-5V-3Cr in relation to local crystallographic orientations. Materials Letters, 2020, 276, pp.128198 -. ⟨10.1016/j.matlet.2020.128198⟩. ⟨hal-03490880⟩