Superplasticity of 5083 aluminum alloy containing Er and Zr
Wang Bo, Gao Kunyuan, Ding Yusheng, Wen Shengping, Huang Hui, Wu Xiaolan, Wei Wu, Nie Zuoren
2023, 48(4):
178-183.
doi:10.13251/j.issn.0254-6051.2023.04.029
Abstract
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Taking 5E83 alloy (Er and Zr microalloyed 5083 alloy) as tested material, the effects of Er and Zr microalloying elements, grain size, deformation temperature and strain rate on superplasticity of the alloy were investigated by means of superplastic tensile test, scanning electron microscope (SEM), electron backscatter diffraction (EBSD) and transmission electron microscope (TEM). Through recrystallization annealing, air cooling and water cooling friction stir processing (FSP), the grain sizes of 7.4, 5.2 and 3.4 μm were obtained, respectively, and used as the initial state for superplastic stretching. The results show that the smaller the initial grain size, the higher the superplastic elongation. When the grain size is greater than 5 μm, the grain coarsening is slow during superplastic deformation, and refining the initial grain can significantly improve superplasticity. However, when the grain size is less than 5 μm, grain coarsening is serious during superplastic deformation, and further refinement of initial grain has limited effect on superplasticity. The superplastic tensile results at different temperatures and strain rates show that when the temperature is in range of 450-540 ℃ and the strain rate is in range of 1.67×10-4-1.67×10-1 s-1, the superplastic elongation first increases, then decreases and then increases with the increase of temperature and strain rate. Under the condition of temperature of 520 ℃ and strain rate of 1.67×10-3 s-1, the water-cooled FSP alloy obtains the largest elongation of 330% corresponding to grain boundary slip superplastic deformation mechanism. The addition of Er and Zr significantly improves the superplasticity, which is mainly due to the formation of nano-dispersed Al3(Er, Zr) phase in Al matrix that can pin the grain boundary and hinder the migration of the grain boundary during superplastic stretching. When the grain size is greater than 5 μm, the Al3(Er, Zr) phase effectively inhibits the grain growth thus improving the superplasticity.
