Abstract
An AA 7075 aluminum alloy with Zr and Sc additions was subjected to 6 – 8 passes of equal-channel angular pressing at 120, 170, and 220 °C in order to study the effect of the pressing conditions on the microstructural characteristics and the consequences for high-temperature mechanical properties. Using the method of electron backscatter diffraction, a decrease in pressing temperature was found to lead to a more pronounced refinement of the microstructure and a higher fraction of high-angle grain boundaries, but at the same time compromised the ability of the Al3 (Zr, Sc) phase to stabilize the ultra-fine-grained microstructure at elevated temperatures. Optimum superplastic properties were therefore achieved after pressing at the intermediate temperature of 170 °C. The material exhibited high strain-rate superplasticity with a ductility of 650 % at an initial strain rate of 1 × 10 – 1 s – 1.
References
[1] A.J.Barnes: Mater. Sci. Forum304–306 (1999) 785.10.4028/www.scientific.net/MSF.304-306.785Search in Google Scholar
[2] R.Kaibyshev, T.Sakai, F.Musin, I.Nikulin, H.Miura: Scripta Mater.45 (2001) 1373.Search in Google Scholar
[3] Glossary of Terms Used in Metallic Superplastic Materials, JIS H 7007, Japanese Standards Association, Tokyo (1995) p. 3.Search in Google Scholar
[4] V.M.Segal, V.I.Reznikov, A.E.Drobyshevskij, V.I.Kopylov: Russ. Metall.1 (1981) 99.Search in Google Scholar
[5] R.Z.Valiev, T.G.Langdon: Prog. Mater. Sci.51 (2006) 881. DOI:10.1016/j.pmatsci.2006.02.00310.1016/j.pmatsci.2006.02.003Search in Google Scholar
[6] A.Yamashita, D.Yamaguchi, Z.Horita, T.G.Langdon: Mater. Sci. Eng. A287 (2000) 100.Search in Google Scholar
[7] Y.C.Chen, Y. Y.Huang, C. P.Chang, P.W.Kao: Acta Mater.51 (2003) 2005. DOI:10.1016/S1359-6454(02)00607-910.1016/S1359-6454(02)00607-9Search in Google Scholar
[8] Y.Y.Wang, P.L.Sun, P.W.Kao, C.P.Chang: Scripta Mater.50 (2004) 613. DOI:10.1016/j.scriptamat.2003.11.02710.1016/j.scriptamat.2003.11.027Search in Google Scholar
[9] A.Goloborodko, O.Sitdikov, R.Kaibyshev, H.Miura, T.Sakai: Mater. Sci. Eng A381 (2004) 121. DOI:10.1016/j.msea.2004.04.04910.1016/j.msea.2004.04.049Search in Google Scholar
[10] I.Mazurina, T.Sakai, H.Miura, O.Sitdikov, R.Kaibyshev: Mater. Sci. Eng A486 (2008) 662. DOI:10.1016/j.msea.2007.09.07010.1016/j.msea.2007.09.070Search in Google Scholar
[11] K.Turba, P.Malek, M.Cieslar: Mater. Sci. Eng. A462 (2007) 91. DOI:10.1016/j.msea.2006.01.17810.1016/j.msea.2006.01.178Search in Google Scholar
[12] R.K.Islamgaliev, N.F.Yunusova, R.Z.Valiev, N.K.Tsenev, V.N.Perevezentsev, T.G.Langdon: Scripta Mater.49 (2003) 467. DOI:10.1016/S1359-6462(03)00291-410.1016/S1359-6462(03)00291-4Search in Google Scholar
[13] J.D.Robson: Acta Mater.52 (2004) 1409. DOI:10.1016/j.actamat.2003.11.02310.1016/j.actamat.2003.11.023Search in Google Scholar
[14] O.Sitdikov, T.Sakai, E.Avtokratova, R.Kaibyshev, K.Tsuzaki, Y.Watanabe: Acta Mater.56 (2008) 821. DOI:10.1016/j.actamat.2007.10.02910.1016/j.actamat.2007.10.029Search in Google Scholar
[15] I.Mazurina, T.Sakai, H.Miura, O.Sitdikov, R.Kaibyshev: Mater. Sci. Eng A473 (2008) 297. DOI:10.1016/j.msea.2007.04.11210.1016/j.msea.2007.04.112Search in Google Scholar
[16] J.K.Mackenzie: Biometrika45 (1958) 229.10.1007/978-3-322-94332-3_9Search in Google Scholar
[17] A.Belyakov, H.Miura, T.Sakai: Philos. Mag. A81 (2003) #2629.10.1080/01418610108216659Search in Google Scholar
[18] A.Goloborodko, O.Sitdikov, T.Sakai, R.Kaibyshev, H.Miura: Mater. Trans.44 (2003) 766.Search in Google Scholar
[19] P. J.Apps, J. R.Bowen, P. B.Prangnell: Acta Mater.51 (2003) 2811. DOI:10.1016/S1359-6454(03)00086-710.1016/S1359-6454(03)00086-7Search in Google Scholar
[20] K.Turba, P.Malek, M.Cieslar: Kovove Mater.45 (2007) 165.Search in Google Scholar
[21] I.Charit, R.S.Mishra: Acta Mater.53 (2005) 4211. DOI:10.1016/j.actamat.2005.05.02110.1016/j.actamat.2005.05.021Search in Google Scholar
[22] K.Turba, P.Malek, E. F.Rauch, M.Cieslar: Mater. Sci. Forum584–586 (2008) 164.Search in Google Scholar
[23] R.Kaibyshev, A.Goloborodko, F.Musin, I.Nikulin, T.Sakai: Mater. Trans.43 (2002) 2408.Search in Google Scholar
[24] C.Xu, M.Furukawa, Z.Horita, T.G.Langdon: Acta Mater.51 (2003) 6139. DOI:10.1016/S1359-6454(03)00433-610.1016/S1359-6454(03)00433-6Search in Google Scholar
© 2009, Carl Hanser Verlag, München
