Superplastic flow in a nanostructured aluminum alloy produced using high-pressure torsion
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- 作者：Cheng Xu ; Sergey V. Dobatkin ; Zenji Horita ; Terence G. Langdon
- 关键词：Aluminum alloy ; High-pressure torsion ; Nanostructured materials ; Severe plastic deformation ; Superplasticity
- 刊名：Materials Science and Engineering: A
- 出版年：2009
- 出版时间：25 January 2009
- 年：2009
- 卷：500
- 期：1-2
- 页码：170-175
- 全文大小：850 K
文摘
Samples of a spray-cast Al-7034 alloy were processed by high-pressure torsion (HPT) at temperatures of 293 or 473 K using an imposed pressure of 4 GPa and torsional straining through five revolutions. Processing by HPT produced significant grain refinement with grain sizes of 60 and 85 nm at the edges of the disks for the two processing temperatures. In tensile testing at room temperature, the alloy processed by HPT exhibited higher strength and lower ductility than the unprocessed material. Good superplastic properties were achieved in tensile testing at elevated temperatures with a maximum elongation of 750 % for the sample processed at 473 K and tested in tension at 703 K under an initial strain rate of 1.0 × 10<sup>−2sup> s<sup>−1sup>. The measured superplastic elongations are lower than in samples prepared by equal-channel angular pressing because of the use of very thin disks in the HPT processing.