Abstract
Ultrafine-grained copper and cooper–zirconium polycrystals prepared by equal-channel angular pressing following the route Bc to various strain (1, 2, 4 and 8 passes) were investigated using electron back-scatter diffraction. Equal-channel angular pressing resulted in significant grain-size reduction. The original course-grained structure evolved from prolate bands of cells/subgrains enclosed by lamellar nonequilibrium grain boundaries (after the first two passes) towards an equiaxed homogeneous microstructure with equilibrium grain boundaries (after 8 passes). Significant changes in the volume fraction and the character of grain boundaries were observed both in Cu and in Cu – Zr alloy. Pronounced evolution of twin-related boundaries (3n grain boundaries) with strain (number of ECAP passes) was found in Cu while only a weak increase of 3 and 9 grain boundaries was observed in Cu – Zr alloys.
References
[1] Investigations and applications of severe plastic deformation. T.C.Lowe, R.Z.Valiev (Eds.), Kluwer, Dordrecht, (2000).10.1007/978-94-011-4062-1Search in Google Scholar
[2] M.Janeček, B.Hadzima, R.J.Hellmig, Y.Estrin: Metall. Mater.43 (2005) 245.Search in Google Scholar
[3] M.JanečekJ.Čížek, M.Dopita, R.Král, O.Srba: Mater. Sci. Forum584–586 (2008) 440.Search in Google Scholar
[4] M.JanečekJ.Čížek, M.Dopita, R.Kužel: J. Alloys Compd., in press.Search in Google Scholar
[5] D.G.Brandon: Acta Metallurgica Vol.14 (1966) 1479.10.1016/0001-6160(66)90168-4Search in Google Scholar
[6] J.K.Mackenzie: Acta Metallurgica Vol.12 (1964) 223.10.1016/0001-6160(64)90191-9Search in Google Scholar
[7] V.Y.Gertsman, M.Janeček, K.Tangri: Acta Metall. Mater.44 (1996) 2869.Search in Google Scholar
[8] O.V.Mishin, V.Y.Gertsman, R.Z.Valiev, G.Gottstein: Scripta Mater.35 (1996) 873.Search in Google Scholar
[9] F.H.Dalla Torre, A.Z.Gazder, E.V.Pereloma, C.H.J.Davis: J. Mater. Sci.42 (2007) 1622.Search in Google Scholar
[10] M.JanečekR.Král, O.Srba, M.Dopita: Metall. Mater., in press.Search in Google Scholar
[11] X.Molodova, A.Khorashadizadeha, G.Gottstein, M.Winning, R.J.Hellmig: Int. J. Mat. Res.98 (2007) 4.Search in Google Scholar
© 2009, Carl Hanser Verlag, München
