Low cycle fatigue behaviour of near α-titanium alloy IMI 834 at room temperature and at 673 K

Abstract

Low cycle fatigue (LCF) behaviour of the near a- titanium alloy IMI 834 was studied, for the (α+β) solution treated, air cooled and stabilized condition, at room temperature (RT) and at 673K. It had bimodal microstructure with nearly 12 vol. % of primary α in the matrix of lamellar transformed β. LCF tests were conducted at different total strain amplitudes (Δεt /2) from ± 0.75% to ± 1.3%, with triangular waveform of loading, at a constant strain rate of 0.008 s -1. While there was cyclic softening at room temperature, there was cyclic hardening followed by softening at 673K. Further, while there was bi-linear behaviour in Coffm-Manson (C-M) relationship at room temperature, there was only linear behaviour at 673K, over the entire range of the total strain amplitude studied.