Influence of hold time on low cycle fatigue behaviour of near alpha titanium alloy IMI 834 at 873K

Abstract In the present work, IMI 834, a near α titanium alloy was evaluated for tensile and low cycle fatigue (LCF, with and without hold time) behavior at 873K. Tensile tests were performed at the initial strain rate of 4 × $ 10^{−3} $ $ s^{−1} $ at 873K. Fully reversed, total strain control LCF t...
Ausführliche Beschreibung

Abstract In the present work, IMI 834, a near α titanium alloy was evaluated for tensile and low cycle fatigue (LCF, with and without hold time) behavior at 873K. Tensile tests were performed at the initial strain rate of 4 × $ 10^{−3} $ $ s^{−1} $ at 873K. Fully reversed, total strain control LCF tests were conducted at total strain amplitude of ± 1.0% at constant strain rate of 4 × $ 10^{−3} $ $ s^{−1} $ at 873K. For LCF tests with dwell, hold time were imposed in tension, compression and tension — compression mode with varied hold times of 60 sec, 120 sec, 180 secs. In LCF tests without dwell, the Coffin-Manson plot showed dual slope behavior at 873K. In LCF tests with dwell, at 873K, tensile, compressive and tensile — compressive hold time tests have shown lower LCF resistance than that of the tests without hold time. Among the three modes of hold times employed, the tensile hold has exhibited the highest LCF resistance followed by tensile — compressive and compressive hold time tests. In the present study, tensile hold introduces compressive mean stresses while the compressive hold introduces tensile mean stresses. Further, the creep effect of stress relaxation was examined at 873K in order to explain the hold time effects. Ausführliche Beschreibung