| Authors: | Lu, Y. Y.; Kotoka, R.; Ligda, J. P.; Yarmolenko, S. N.; Schuster, B. E.; Wei, Q. |
| Title: | Morphological and mechanical stability of HCP-based multilayer nanofilms at elevated temperatures |
| Type: | Journal Article |
| Publisher: | Surface and Coatings Technology |
| Year: | 2015 |
| Volume: | 275 |
| Issue: | |
| Start Page: | 142 |
| End Page: | 147 |
| DOI: | 10.1016/j.surfcoat.2015.05.027 |
| WEB-link: | http://ac.els-cdn.com/S0257897215300268/1-s2.0-S0257897215300268-main.pdf?_tid=7b4abf7e-0dbb-11e6-895c-00000aacb361&acdnat=1461901136_ef587e9886c8fa8c29344f8219f1293b |
| Abstract: | The thermal stability of Mg/Ti multilayer nanofilms was investigated by examining their microstructure and nanoindentation hardness after annealing at various temperatures and time periods. The multilayers with individual layer thickness h >= 5 nm exhibit excellent capability of maintaining the lamellar microstructure and high strength up to 200 degrees C for annealing time up to 2.0 h. The annealed muldlayer films with h = 2.5 nm are still highly textured but characterized with discontinuous layer interfaces, in which the transition of atomic arrangement from hexagonal close-packed (HCP) to body-centered cubic (BCC) structure was observed at columnar boundaries. The degradation of uniform lamellar microstructure is related to the decrease of hardness with annealing temperature at this size scale. A diffusion based instability mechanism was proposed for this typical HCP-based nanoscale multilayer system. (C) 2015 Elsevier B.V. All rights reserved. |
| Keywords: | metallic multilayer, thermal stability, microstructure, nanoindentation hardness, scale-dependent deformation, plate-like structures, thermal-stability, shape instabilities, magnetic-properties, co/cu multilayers, phase-transition, columnar growth, thin-films, microstructure |
