Cu/Zr nanoscaled multi-stacks fabricated by accumulative roll bonding

In this paper, six pure Cu (99.96 mass%) and five pure Zr (99.8 mass%) sheets with overall composition of Cu62Zr38 (at%) were alternatively stacked and severely deformed up to equivalent strain (epsilon) of 14.4 by accumulative roll bonding (ARB) technique at ambient temperature. During the ARB process, every individual Cu and Zr sheet in the multi-stacked materials decreases greatly in thickness with the increase of e. Finally, nanolamellar structure with single layer thickness of about 20nm can be obtained in the ARB processed Cu/Zr multi-stacks. Tensile tests were used to evaluate the mechanical properties of the ARB processed Cu/Zr multi-stacks related to the variations of epsilon. It reveals that the tensile strength increases greatly from 570MPa at epsilon = 1.6 to 1210MPa at epsilon = 14.4. However, the plastic elongation first increases from 8% at epsilon = 1.6 to 14% at epsilon = 9.6 and then decrease to 6% at epsilon = 14.4. The equivalent strain dominated microstructural evolution and deformation behavior of the ARB fabricated multi-stacks were put forward and discussed. (C) 2010 Elsevier B.V. All rights reserved.