Achieving high strain rate superplasticity of an Al-Mg-Sc-Zr alloy by a new asymmetrical rolling technology

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• 作者：Guofu Xu^a ; ^b ; ^c ; ^{csuxgf66@csu.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; Xiaowu Cao^a ; Tao Zhang^d ; Yulu Duan^a ; Xiaoyan Peng^a ; Ying Deng^a ; ^b ; ^c ; ^{csudengying@163.com" class="auth_mail" title="E-mail the corresponding author} ; Zhimin Yin^a
• 关键词：Al-Mg-Sc-Zr alloy ; Superplasticity ; Grain boundary sliding ; Asymmetrical rolling
• 刊名：Materials Science & Engineering A
• 出版年：2016
• 出版时间：30 August 2016
• 年：2016
• 卷：672
• 期：Complete
• 页码：98-107
• 全文大小：5191 K

文摘

Superplastic property and microstructure evolution during the deformation of an Al-6.10Mg-0.25Sc-0.1Zr alloy with fine grains, produced by a new asymmetrical rolling technology, were investigated by tensile tests and microscopy methods. The results show that new asymmetrical rolling can considerably enhance the high strain rate superplasticity. A maximum ductility of 3200% can be achieved at 500 °C and 5×10⁻² s⁻¹. Under the same cold rolling reduction (75%), although the maximum elongation is comparable to that of the traditionally rolled same materials, asymmetrical rolling can increase the optimum strain rate up to 10 times. The microstructure results show that, during superplastic deformation, low angle grain boundaries gradually transfer into high angle grain boundaries and the grains gradually orientate randomly. The excellent high stain rate superplasticity can be ascribe to the refined grains and the presence of nano-scaled Al₃(Sc, Zr) particles which can stabilize the fine-grains during hot deformation. The grain boundary sliding is the predominant superplastic deformation mechanism in the studied alloy.