Abstract
To explore the effective way of grain refinement for 2219 aluminum alloy, the approach of ‘thermal compression tests + solid solution treatment experiments’ was applied to simulate the process of intermediate thermo-mechanical treatment. The effects of deformation parameters (i.e., temperature, strain, and strain rate) on microstructural evolution were also studied. The results show that the main softening mechanism of 2219 aluminum alloy during warm deformation process is dynamic recovery, during which the distribution of CuAl2 phase changes and the substructure content increases. Moreover, the storage energy is found to be decreased with the increase in temperature and/or the decrease in strain rate. In addition, complete static recrystallization occurs and substructures almost disappear during the solid solution treatment process. The average grain size obtained decreases with the decrease in deforming temperature, the increase in strain rate, and/or the increase in strain. The grain refinement mechanism is related to the amount of storage energy and the distribution of precipitated particles in the whole process of intermediate thermal-mechanical treatment. The previously existing dispersed fine precipitates are all redissolved into the matrix, however, the remaining precipitates exist mainly by the form of polymerization.
Highlights
2219 aluminum alloy, which has the advantages of high strength and resistance to stress corrosion, good weldability, and service performance, was considered as the third generation of space materials and has been widely used in aerospace industry [1]
For 2219 aluminum alloy that can be strengthened by heat treatment, solid solution strengthening and precipitation strengthening are effective means to improve its strength [3,4,5]
Some fine recrystallized grains are found at local grain boundaries, which indicates dynamic recrystallization initiated during hot rolling
Summary
2219 aluminum alloy, which has the advantages of high strength and resistance to stress corrosion, good weldability, and service performance, was considered as the third generation of space materials and has been widely used in aerospace industry [1]. For 2219 aluminum alloy that can be strengthened by heat treatment, solid solution strengthening and precipitation strengthening are effective means to improve its strength [3,4,5]. Concerning the improvement of ductility, the grain refinement approach may be often applied [6]. Grain refinement is the only method that can effectively improve both the ductility and the strength of the materials [7,8]. The theory and technology of grain refinement for 2219 aluminum alloy are of great significance to be investigated
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