Nanostructured Cu–Al alloys with different stacking fault energies corresponding to Al concentrations in a range of 0 to 4.5wt% were prepared by means of plastic deformation. The effects of stacking fault energy, strain rate and temperature on microstructure characteristics and strength were systematically investigated in the Cu–Al alloys. It was found that the deformation occurred mainly by twinning at the nanoscale in all samples subjected to dynamic plastic deformation at liquid nitrogen temperature. In the quasi-static compression process at room temperature, dislocation slip dominates the plastic deformation when the stacking-fault energy was higher than 50mJ/m2. With decreasing stacking fault energy, twinning becomes the dominant deformation mechanism. A map of deformation modes and corresponding strain-induced microstructures was drawn in the stacking fault energy-processing parameters space for the Cu–Al alloys. In both sets of deformation mode, twinning was obviously enhanced by decreasing the stacking fault energy, resulting in smaller twin/matrix lamella thickness and grain sizes. Consequently, an obvious strength elevation was induced by the size effects of grains and twin/matrix lamellae with lower stacking fault energies.

Effects of Stacking Fault Energy, Strain Rate and Temperature on Microstructure and Strength of Nanostructured Cu–Al Alloys Subjected to Plastic Deformation. Y.Zhang, N.R.Tao, K.Lu: Acta Materialia, 2011, 59[15], 6048-58