Influence of solute cloud and precipitates on spatiotemporal characteristics of Portevin-Le Chatelier effect in A2024 aluminum alloys

In this paper, solute concentration and precipitate content in A2024 aluminum alloy are adjusted by solution treatment (ST) at different temperatures and tensile experiments on these treated specimens are carried out. It is found that the temperature of solution treatment (ST temperature) has a remarkable influence on the amplitude of the serrated flow and the propagation characteristics of shear bands. These results are due to the effects of solute atoms and precipitates on dynamic strain aging (DSA). When ST temperature is higher than 300 °C, solute concentration is relatively high and solute cloud is a key factor of DSA. When ST temperature is lower than 300 °C, precipitate content is relatively high and the mechanism of DSA is determined by precipitates. (condensed matter: structure, thermal and mechanical properties)