Plastic Flow Properties and Microstructural Evolution in an Ultrafine-Grained Al-Mg-Si Alloy at Elevated Temperatures
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An AA6082 alloy was subjected to eight passes of equal channel angular pressing at 100 °C, resulting in an ultrafine grain size of 0.2 to 0.4 μm. The tensile deformation behavior of the material was studied over the temperature range of 100 °C to 350 °C and strain rate range of 10−4 to 10−1 s−1. The evolution of microstructure under tensile deformation was investigated by analyzing both the deformation relief on the specimen surface and the dislocation structure. While extensive microshear banding was found at the lower temperatures of 100 °C to 150 °C, deformation at higher temperatures was characterized by cooperative grain boundary sliding and the development of a bimodal microstructure. Dislocation glide was identified as the main deformation mechanism within coarse grains, whereas no dislocation activity was apparent in the ultrafine grains.
The authors acknowledge financial support from the Australian Research Council through the ARC Centre of Excellence for Design in Light Metals and the Federation Fellowship awarded to PH. IS and MB thank Deakin University for partial funding through the Central Research Grants Scheme. Assistance of Dr. Pavel Cizek with TEM work is acknowledged. Useful discussions with Professor David Embury are much appreciated.
- 4.M. Cabibbo, C. Scalabroni, and E. Evangelista: Metall. Sci. Technol., 2006, vol. 24, pp. 31–40.Google Scholar
- 8.I.J. Polmear: Light Alloys—Metallurgy of the Light Metals, Arnold, London, 1995.Google Scholar
- 21.I. Sabirov, Y. Estrin, M.R. Barnett, I. Timokhina, and P.D. Hodgson: Scripta Mater., 2008, vol. 58, pp. 163–66.Google Scholar
- 30.P.B. Hirsch, R.B. Nicholson, A. Howie, D.W. Pashley, and M.J. Whelan: Electron Microscopy of Thin Crystals, Butterworth and Co., London, 1965.Google Scholar
- 36.E. Cerri and P. Leo: Mater. Sci. Eng. A, 2005, vols. 410–411, pp. 226–29.Google Scholar
- 37.R. Islamgaliev, N. Yunusova, I. Sabirov, A. Sergueeva, and R. Valiev: Mater. Sci. Eng. A, 2001, vols. 319–321, pp. 877–81.Google Scholar
- 38.D. Caillard and J.L. Martin: Thermally Activated Mechanisms in Crystal Plasticity, Pergamon Materials Series, Elsevier, Oxford, United Kingdom, 2003, vol. 8.Google Scholar
- 42.A. Vinogradov, S. Hashimoto, V. Patlan, and K. Kitagawa: Mater. Sci. Eng. A, 2001, vols. 319–321, pp. 862–66.Google Scholar
- 45.H.J. Frost and M.F. Ashby: Deformation Mechanism Maps, Pergamon Press, Oxford, United Kingdom, 1982.Google Scholar
- 49.N. Balasubramanian and T.G. Langdon: Mater. Sci. Eng. A., 2005, vols. 410–411, pp. 476–79.Google Scholar
- 51.U.F. Kocks: Encyclopedia of Materials: Science and Technology, Elsevier, Oxford, 2008, pp. 7084–88.Google Scholar