Abstract
Corrosion fatigue of pure copper single crystals having a single activated slip system in aquious 1M NaNO2 solutions was investigated by focusing on the effect of anodic potential and role of persistent slip bands (PSBs) on the crack nucleation. The number of cycles to fracture is lowest under 100mV vs. Ag/AgCl followed by those under 0 and 250mV vs. Ag/AgCl. Potential of 100mV corresponds to where sensitivity of the transgranular stress corrosion cracking (TGSCC) in pure copper was reported to be highest under monotonic tensile deformation in a slow strain rate test. A number of cracks were observed at PSBs under 100mV vs. Ag/AgC, and plane of the cracks corresponds to {110} plane normal to applied tensile axis. Crystallographic features of the cracks formed under 100mV vs. Ag/AgCl were similar to those of TGSCC of pure copper single crystals deformed monotonically. Anodic current increased when the Bauschinger energy parameter βe showed a peak, suggesting that cracks formed along the PSBs. It is suggested that the cracks formed by the same mechanism of TGSCC in pure copper, and PSBs play an important role in nucleation of cracks under cyclic deformation.
