Response of Cu-Nb Nanolamellar Composites to Severe Rolling Strains.

摘要

The use of rolling and accumulative roll bonding (ARB) as alternate techniques to physical vapor deposition in the fabrication of metallic multilayer composites with nanoscale layer thicknesses is explored. Cu/Nb multilayers with individual layer thicknesses ranging from tens of microns to tens of nanometers are fabricated via ARB after initially starting with single layers of polycrystalline Cu and Nb. Neutron diffraction and transmission electron microscopy are performed and it is found that a texture characteristic of severe plastic deformation stabilizes when layer thickness is reduced to the submicron range. Orientation distribution function analysis indicates an appearance of Alpha fibers in Cu and the loss of Gamma fibers in Nb during transition from the rolling texture. Viscoplastic self-consistent modeling argues an increase in active slip systems in the Nb and a tendency towards planar slip in the Cu are responsible for the characteristic texture.