Plastic deformation and fatigue properties of CoZr single crystals at room and high temperatures

摘要

Plastic deformation behaviour of CoZr single crystals was examined in monotonic and cyclic loading modes. It was shown that with increasing temperature the yield stress of CoZr single crystal increased and reached a maximum peak at 1023 K. The cross-slip took place on non-crystallographic planes. Cross-slip on orthogonal (1 1 0) was promoted with temperature, and the yield stress increased. The fatigue behaviour of this single crystal also was investigated. Because of good ductility, the fatigue life was fairly good. Maximum fatigue life occurred at a temperature lower than the peak temperature in yield stress. Crack initiation and propagation were difficult due to the release of residual stress by cross-slip, but activation of secondary slip system promoted crack initiation.