Universal strain-temperature dependence of dislocation structure evolution in face-centered-cubic metals

The combined effect of strain and temperature on the microstructural evolution of plastically deformed face-centered-cubic (fcc) metals is explored systematically. In particular, the detailed nanoscale, internal structure of dislocation boundaries is determined in pure polycrystalline aluminum, nickel and gold and compared to earlier results in copper. In all the metals studied, dislocations within the boundaries tend to rearrange themselves with increasing strain in the same sequence from tangles into dislocation cells with tangled boundaries, followed by dislocation boundaries consisting of wavy, parallel dislocations and finally into arrays of parallel dislocations. The strain at which rearrangement occurs decreases with increasing temperature. The results are represented by microstructural maps on the strain-temperature plane. The topology of the microstructural maps is found to be similar for all metals studied, suggesting a universal strain-temperature dependence in deformed fcc metals.