Grain refinement, thermal stability and tensile properties of 2024 aluminum alloy after equal-channel angular pressing

The microstructure evolution and tensile properties of 2024 aluminum alloy after severe plastic deformation by equal-channel angular pressing (ECA pressing) have been studied with different initial aging treatment conditions. The experimental results reveal that ECA pressing produces ultrafine grains to a submicrometer level of around 0.25 μm in both peak- and over-aged specimens. Moreover, these ultrafine grains have limited grain growth when ECA pressings are subsequently annealed at temperatures upto 300 °C. The values of 0.2% proof stress and ultimate tensile stress (UTS) are improved without significant loss of ductility for both peak- and over-aged specimens after various passages of ECA pressing at two temperatures of 150 and 190 °C. An optimum tensile property was achieved in a peak-aged specimen after eight passages of ECA pressing at a temperature of 150 °C.