Microstructural investigations into the low cycle fatigue deformation of a Cu–Cr–Zr–Ti alloy

Fully reversed axial strain controlled low cycle fatigue behaviour of a Cu–Cr–Zr–Ti alloy was investigated in the solution-annealed condition. Temperatures in the range, 300–900 K were employed for the tests which were carried out at a constant strain rate of 3×10−3 s−1. The cyclic stress response was found to vary as a function of the test temperature, with a strong secondary hardening occurring in the range, 673–773 K which was associated with the formation of Cr-rich precipitates. Prior thermal ageing served to shift the cyclic stress response upwards and caused disappearance of the secondary hardening regime. Further, the serrations in the stress–strain hysteresis loops observed at the test temperature of 900 K remained absent in samples tested after the prior ageing treatment. The results are explained on the basis of microstructural observations.