Influence of test temperature on cyclic deformation behavior of a near a titanium alloy

摘要

Low cycle fatigue behavior of titanium alloy Timetal 834 has been studied at 300 ℃, 450 ℃ and 600 ℃ under fully reversed constant total strain amplitudes (Δε_t/2) ranging from 0.4% to 1.2%. The alloy exhibited initial cyclic softening followed by cyclic hardening at 450 ℃ for Δε_t/2 ≥ 0.4% while at 300 ℃ and 600 ℃, cyclic softening followed by cyclic stability was noticed in the cyclic stress response curves for Δε_t/2 ＞ 0.4%. Precipitate shearing was observed to be the micro-mechanism responsible for cyclic softening at all test temperatures. However, dislocation-dislocation and dislocation - solute interaction was observed to be the micro-mechanism responsible for cyclic hardening only at 450 ℃. TEM observations revealed that the severity of planar slip is found to peak at 450 ℃.