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High-resolution transmission electron microscopy investigation of diffusion in metallic glass multilayer films

Ketov, S. V. and Ivanov, Yu P. and Sopu, D. and Louzguine-Luzgin, D. V. and Suryanarayana, C. and Rodin, A. O. and Schöberl, T. and Greer, A. L. and Eckert, J. (2019):
High-resolution transmission electron microscopy investigation of diffusion in metallic glass multilayer films.
In: Materials Today Advances, 12019. Elsevier Ltd., p. 100004, ISSN 25900498,
DOI: 10.1016/j.mtadv.2019.01.003,
[Online-Edition: https://doi.org/10.1016/j.mtadv.2019.01.003],
[Article]

Abstract

Lack of plasticity is one of the main disadvantages of metallic glasses. One of the solutions to this problem can be composite materials. Diffusion bonding is promising for composite fabrication. In the present work the diffusion process in glassy multilayer films was investigated. A combination of advanced transmission electron microscopy (TEM) methods and precision sputtering techniques allows visualization and study of diffusion in amorphous metallic layers with high resolution. Multilayered films were obtained by radio frequency sputter deposition of Zr-Cu and Zr-Pd. The multilayers were annealed under a high vacuum (10−5 Pa) for 1 and 5 h at 400 °C, that is, well below the crystallization temperatures but very close to the glass-transition temperatures of both types of the glassy layer. The structural evolution in the deposited films was investigated by high-resolution transmission electron microscopy. It was observed that, despite the big differences in the atomic mass and size, Pd and Cu have similar diffusion coefficients. Surprisingly, 1 h of annealing results in formation of metastable copper nanocrystals in the Zr-Cu layers which, however, disappear after 5 h of annealing. This effect may be connected with nanovoid formation under a complex stress state evolving upon annealing, and is related to the exceptionally slow relaxation of the glassy layers sealed with a Ta overlayer.

Item Type: Article
Erschienen: 2019
Creators: Ketov, S. V. and Ivanov, Yu P. and Sopu, D. and Louzguine-Luzgin, D. V. and Suryanarayana, C. and Rodin, A. O. and Schöberl, T. and Greer, A. L. and Eckert, J.
Title: High-resolution transmission electron microscopy investigation of diffusion in metallic glass multilayer films
Language: English
Abstract:

Lack of plasticity is one of the main disadvantages of metallic glasses. One of the solutions to this problem can be composite materials. Diffusion bonding is promising for composite fabrication. In the present work the diffusion process in glassy multilayer films was investigated. A combination of advanced transmission electron microscopy (TEM) methods and precision sputtering techniques allows visualization and study of diffusion in amorphous metallic layers with high resolution. Multilayered films were obtained by radio frequency sputter deposition of Zr-Cu and Zr-Pd. The multilayers were annealed under a high vacuum (10−5 Pa) for 1 and 5 h at 400 °C, that is, well below the crystallization temperatures but very close to the glass-transition temperatures of both types of the glassy layer. The structural evolution in the deposited films was investigated by high-resolution transmission electron microscopy. It was observed that, despite the big differences in the atomic mass and size, Pd and Cu have similar diffusion coefficients. Surprisingly, 1 h of annealing results in formation of metastable copper nanocrystals in the Zr-Cu layers which, however, disappear after 5 h of annealing. This effect may be connected with nanovoid formation under a complex stress state evolving upon annealing, and is related to the exceptionally slow relaxation of the glassy layers sealed with a Ta overlayer.

Journal or Publication Title: Materials Today Advances
Volume: 1
Publisher: Elsevier Ltd.
Uncontrolled Keywords: Metallic glasses, Multilayered films, Diffusion, HRTEM
Divisions: 11 Department of Materials and Earth Sciences
11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences > Material Science > Materials Modelling
Date Deposited: 28 Jan 2020 07:25
DOI: 10.1016/j.mtadv.2019.01.003
Official URL: https://doi.org/10.1016/j.mtadv.2019.01.003
Projects: SO 1518/1-1
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