The significance of grain boundary sliding in the superplastic Zn-22 % Al alloy processed by ECAP
- Title
- The significance of grain boundary sliding in the superplastic Zn-22 % Al alloy processed by ECAP
- Author
- Megumi Kawasaki
- Keywords
- DEFORMATION-MECHANISM MAPS; SEVERE PLASTIC-DEFORMATION; HIGH-TEMPERATURE CREEP; HIGH-PRESSURE TORSION; ZN-22-PERCENT AL; ALUMINUM-ALLOY; MICROSTRUCTURAL EVOLUTION; ACTIVATION-ENERGIES; INTER-CRYSTALLINE; NECK FORMATION
- Issue Date
- 2013-07
- Publisher
- SPRINGER, 233 SPRING ST, NEW YORK, NY 10013 USA
- Citation
- JOURNAL OF MATERIALS SCIENCE 권: 48 호: 13 페이지: 4730-4741
- Abstract
- A Zn-22 % Al eutectoid alloy was processed by equal-channel angular pressing (ECAP) to reduce the grain size to similar to 0.8 mu m. Tensile testing at 473 K showed superplastic characteristics with a maximum elongation of similar to 2230 % at a strain rate of 1.0 x 10(-2) s(-1). The significance of grain boundary sliding (GBS) was evaluated by measuring sliding offsets at adjacent grains from the displacements of surface marker lines in samples pulled to elongations of 30 % at a series of different strain rates. The highest sliding contribution was recorded under testing conditions corresponding to the maximum superplastic ductility. There were relatively large offsets at the Zn-Zn and Zn-Al interfaces, but smaller offsets at the Al-Al interfaces. Analysis shows the results are affected by the presence of agglomerates of similar grains which are present after ECAP processing and specifically by the increased fraction of Al-Al boundaries. The experimental results are in excellent agreement with the predictions of a deformation mechanism map depicting the flow behavior in the Zn-22 % Al alloy, and the results confirm the importance of GBS as the dominant mechanism of flow in superplasticity after processing by ECAP.
- Description
- European Research Council under ERC
- URI
- http://dx.doi.org/10.1007/s10853-012-7104-9http://hdl.handle.net/20.500.11754/44204
- ISSN
- 0022-2461
- DOI
- 10.1007/s10853-012-7104-9
- Appears in Collections:
- COLLEGE OF ENGINEERING[S](공과대학) > MATERIALS SCIENCE AND ENGINEERING(신소재공학부) > Articles
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