Effect of texture and ramp loading on the cyclic response and dislocation substructure of copper polycrystals

Abstract

Fatigue tests were carried out on copper polycrystals that had a texture with strong components along directions inside the standard stereographic triangle (single slip orientations in monocrystals). The experiments showed that this “single slip” texture, ramp loading as a mechanical pretreatment and extended cycling at a given stress to insure saturation provide the conditions to obtain a plateau in the Cyclic Stress–Strain Curve (CSSC) of copper polycrystals in a reproducible fashion. Transmission Electron Microscopy (TEM) studies revealed the presence of numerous Persistent Slip Bands (PSB's) in samples deformed within the plateau regime.