Low Cycle Fatigue Strength of Copper and α-brass Cold-worked

Cold-worked copper and α-brass, which have wavy and planar slip modes, respectively, were low cycle fatigued, and the relation between the fatigue life and the cyclic softening behavior was discussed in terms of the slip mode. The amount of cyclic softening is much larger in copper than in α-brass, and the fracture ductility in the latter is much more influenced than in the former by the cold-work. The cyclic softening behavior and the cold-work dependent fracture ductility might be interpreted by a common factor of the relative difficulty in the cross slip of the screw dislocation. The decrease in the low cycle fatigue life caused by the cold-work is closely related with the above cyclic softening characteristic and the fracture ductility. On the other hand, the microscopic configuration of slip line is also important for understanding the cold-work dependent fatigue life.