Influence of stacking fault energy and temperature on microstructures and mechanical properties of fcc pure metals processed by equal-channel angular pressing

Three fcc pure metals-Cu, Ni, and Al, with the same purity level (similar to 99.99 wt%) and different stacking fault energies (SFEs, about 45 mJ/m(2), 125 mg/m(2), and 166 mJ/m(2), respectively) are processed by equal-channel angular pressing (ECAP) at different temperatures (room temperature, 0.32T(m), and 0.4T(m)). A dislocation density-based model is improved by introducing a material-dependent parameter, and the improved model is utilized to predict the evolution of dislocation density, grain size, and strength of materials processed by ECAP processing. The predicted dislocation density, grain size, and strength are compared with the experimental results, with satisfactory agreement. The influence of the SFE on the steady-state grain size d(s) is discussed, based on the experimental and modeling results. It is demonstrated that at the same homologous temperatures, the dependence of the d(s) on the SFE exists, and that a reduction in the SFE leads to a decrease in the d(s), in case there is no recrystallization in the samples. In addition, increasing deformation temperature leads to a decrease in the dislocation densities and an increase in the steady-state grain size d(s). The predicted values of the d(s) match well with the experimental results at lower homologous temperatures. (C) 2016 Elsevier B.V. All rights reserved.