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EBSD investigation of the grain boundary distributions in ultrafine-grained Cu and Cu–Zr polycrystals prepared by equal-channel angular pressing

Milan Dopita, Miloš Janeček, David Rafaja, Jaromír Uhlíř, Zdeněk Matěj and Radomír Kužel

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.


* Correspondence address, Milan Dopita, TU Bergakademie Freiberg, Institute of Materials Science, Gustav-Zeuner-Straße 5, D-09599 Freiberg, Germany, Tel.: +49 3731 39 2095, Fax: +49 3731 39 3657, E-mail:

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Received: 2008-8-28
Accepted: 2009-4-2
Published Online: 2013-06-11
Published in Print: 2009-06-01

© 2009, Carl Hanser Verlag, München