Work Hardening of Cu-10 at%Al Alloy Single Crystals at High Temperatures

Cu-10 at%Al alloy single crystals with [102], [001], and [111] axes were extended in a temperature range between 400 and 800°C. Upper serration (yield) stress increased with temperature between 400 and 600°C, and the increments were largest in [102] crystals. Above 600°C the upper yield stress was almost independent of crystal orientations. The work-hardening rate in [001] and [111] crystals had a sharp maximum around 600°C, which was explained that an ideally multiple glide was attained after the serrated flow, but this effect was absent in [102] crystals. The observed result was discussed on the basis of a simple model in which the pinning and dragging effects were treated by single activation processes of solute atoms in dislocation cores, respectively