Effect of heat treatment on low cycle fatigue properties of Cu-Cr-Zr alloy

In this work, the fatigue properties and cyclic deformation behavior of cold-drawn and annealed Cu-Cr-Zr alloys were investigated via low-cycle fatigue (LCF) testing at room temperature. The microstructure and fatigue fracture of the alloy were analyzed by scanning electron microscopy, electron backscattered diffraction, and transmission electron microscopy. The results show that because of recrystallization grain growth during the annealing process, the LCF life of the annealed Cu-Cr-Zr alloy were lower than those of the cold-drawn Cu-Cr-Zr alloy when the total strain amplitude was less than or equal to 0.7%. The cold-drawn Cu-Cr-Zr alloy exhibits the Bauschinger effect at low total strain amplitudes (0.4% and 0.45%). In addition, the initiation and propagation of fatigue cracks of the two alloys occurred in a transgranular manner. The evolution of the cyclic microstructure of the two selected materials after different total strain amplitudes was significantly different, the dislocation density of cold-drawn Cu-Cr-Zr alloy decreases with the increase of the total strain amplitude, while that of the annealed Cu-Cr-Zr alloy increases.