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

Low cycle fatigue behavior of titanium alloy Timetal 834 has been studied at 300 °C, 450 °C and 600 °C under fully reversed constant total strain amplitudes (Δεt/2) ranging from 0.4% to 1.2%. The alloy exhibited initial cyclic softening followed by cyclic hardening at 450 °C for Δεt/2≥0.4% while at 300 °C and 600 °C, cyclic softening followed by cyclic stability was noticed in the cyclic stress response curves for Δεt/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 °C. TEM observations revealed that the severity of planar slip is found to peak at 450 °C.