Predicting ECAP misorientation evolution and its influence on superplasticity for an Al-Zn-Mg-Cu alloy

Abstract

Abstract. Extensive research on severe plastic deformation (SPD) of metallic materials has been performed so far in order to improve mechanical properties, both at low and high temperatures. As a result of the extensive grain refinement obtained, increased superplastic behaviour has been attained at higher strains rates and lower temperatures than usual. This is due to finer grain sizes and higher average misorientations obtained, which enhance grain boundary sliding (GBS). However, the misorientation effect on superplasticity, and the prediction of misorientation evolution during SPD has remained so far, qualitative. In this research, especial attention has been given to the quantitative misorientation evolution with increasing equal channel angular pressing (ECAP) deformation, in order to propose an expression useful to describe and predict the influence of the different processing parameters on the misorientation evolution with strain. This is exemplified for ECAPed Al-Zn-Mg-Cu and other aluminium alloys, and it could serve as a basis for predicting the misorientation evolution, and its influence on superplasticity, of other SPD processes and metallic alloys.