Overview on the microstructure and mechanical properties of ultrafine-grained Al-Li alloys produced by severe plastic deformation

Abstract:

In recent years, fabrication of bulk ultrafine-grained (UFG) Al-Li alloys via severe plastic deformation (SPD) techniques has been investigated to improve properties for expanding its applications as structural products. This review reveals microstructure and mechanical properties of Al-Li alloys produced by SPD techniques. It focuses on the microstructure evolution during SPD, with the influence of internal and external factors. The strengthening mechanism of Al-Li alloys mainly based on precipitation hardening is presented. It is demonstrated that UFG Al-Li may attain enhanced strength with relatively good ductility via grain refinement and multiple precipitates. Special attention is given to the superplasticity of UFG Al-Li alloys, especially to the high strain rate superplasticity (HSR SP). It suggests that UFG Al-Mg-Li alloy produced by SPD, particularly by equal-channel angular pressing (ECAP), is a promising candidate material for use in superplastic forming operations.