The microstructure and high temperature mechanical behavior of textured, polycrystalline Cu-Nb nanolayered composites prepared by magnetron sputtering were evaluated. Layer thicknesses of 75, 60, and 40 nm were tested in an effort to investigate the high temperature mechanical properties of freestanding thin film multilayers. Effects of decreasing layer thickness on high temperature properties show a dependence of strength and ductility on layer thickness and test temperature. Fracture surface analysis, along with strain rate jump test results, show boundary sliding as a probable deformation mechanism under certain conditions. The role of elevated-temperature deformation mechanisms such as interlayer and grain boundary sliding are discussed. (c) 2006 Elsevier B.V. All rights reserved.