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

Fatigue tests were carried out on copper polycrystals that had a texture wi th strong components along directions inside the standard stereographic tri angle (single slip orientations in monocrystals). The experiments showed th at this "single slip" texture, ramp loading as a mechanical pretreatment an d extended cycling at a given stress tp insure saturation provide the condi tions to obtain a plateau in the Cyclic Stress-Strain Curve (CSSC) of coppe r 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. (C) 1999 Elsevier Science Ltd. All rights reserved.