Improving the mechanical properties of 2024 Al alloy by cryo rolling

Abstract

Ultra fine grained (1 micron size) materials usually exhibit more strength. Most of the approaches to refine microstructure lead to decrease in ductility. Cryo rolling is a successful technique; samples are rolled at cryogenic temperature, to improve strength of an age hardenable alloy with minimum loss in ductility. Aging after cryo rolling ensures good strength and ductility due to bimodal structure and nano sized precipitation of S' phase. Al 2024 alloy are partially solutionised to retain some T-phase particles, which are very effective in accumulating dislocations during cryo-rolling, and in turn promoted the precipitation of Al(2)CuMg precipitates with a size of 10-40 nm. The nano sized Al(2)CuMg precipitates and bimodal grain structure leads to simultaneous increases in strength and ductility.