Mechanical Properties of Thermally Annealed Cu/Ni and Cu/Al Multilayer Thin Films: Solid Solution vs. Intermetallic Strengthening

In this study, Cu/Ni and Cu/Al multilayers, with individual layer thickness varying from 25 nm to 200 nm, and co-sputtered Cu-Ni and Cu-Al single layer films were deposited at room temperature via magnetron sputtering and further annealed from 100 °C to 300 °C. The mechanical and microstructural pro...

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Main Authors: Yang Zhou, Junlan Wang
Format: Article
Language:English
Published: MDPI AG 2024-02-01
Series:Metals
Subjects:
Online Access:https://www.mdpi.com/2075-4701/14/3/256
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author Yang Zhou
Junlan Wang
author_facet Yang Zhou
Junlan Wang
author_sort Yang Zhou
collection DOAJ
description In this study, Cu/Ni and Cu/Al multilayers, with individual layer thickness varying from 25 nm to 200 nm, and co-sputtered Cu-Ni and Cu-Al single layer films were deposited at room temperature via magnetron sputtering and further annealed from 100 °C to 300 °C. The mechanical and microstructural properties of the as-deposited and annealed samples were characterized by nanoindentation, x-ray diffraction, and scanning electron microscopy. Both multilayer systems exhibit an increase in hardness with increasing annealing temperature. However, the Cu/Ni system shows a gradual and moderate hardness increase (up to 30%) from room temperature to 300 °C, while the Cu/Al system displays a sharp hardness surge (~150%) between 125 °C and 200 °C. The co-sputtered Cu-Ni and Cu-Al samples consistently demonstrate higher hardness than their multilayered counterparts, albeit with distinctly different temperature dependence—the hardness of Cu-Ni increases with annealing temperature while Cu-Al maintains a constant high hardness throughout the entire temperature range. The distinct thermal strengthening mechanisms observed in the two metallic multilayer systems can be ascribed to the formation of solid solutions in Cu/Ni and the precipitation of intermetallic phases in Cu/Al. This study highlights the unique advantage of intermetallic strengthening in metallic multilayer systems.
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spelling doaj.art-bce99649f9df4b3d8ce09582e9797a012024-03-27T13:54:14ZengMDPI AGMetals2075-47012024-02-0114325610.3390/met14030256Mechanical Properties of Thermally Annealed Cu/Ni and Cu/Al Multilayer Thin Films: Solid Solution vs. Intermetallic StrengtheningYang Zhou0Junlan Wang1Department of Mechanical Engineering, University of Washington, Seattle, WA 98195, USADepartment of Mechanical Engineering, University of Washington, Seattle, WA 98195, USAIn this study, Cu/Ni and Cu/Al multilayers, with individual layer thickness varying from 25 nm to 200 nm, and co-sputtered Cu-Ni and Cu-Al single layer films were deposited at room temperature via magnetron sputtering and further annealed from 100 °C to 300 °C. The mechanical and microstructural properties of the as-deposited and annealed samples were characterized by nanoindentation, x-ray diffraction, and scanning electron microscopy. Both multilayer systems exhibit an increase in hardness with increasing annealing temperature. However, the Cu/Ni system shows a gradual and moderate hardness increase (up to 30%) from room temperature to 300 °C, while the Cu/Al system displays a sharp hardness surge (~150%) between 125 °C and 200 °C. The co-sputtered Cu-Ni and Cu-Al samples consistently demonstrate higher hardness than their multilayered counterparts, albeit with distinctly different temperature dependence—the hardness of Cu-Ni increases with annealing temperature while Cu-Al maintains a constant high hardness throughout the entire temperature range. The distinct thermal strengthening mechanisms observed in the two metallic multilayer systems can be ascribed to the formation of solid solutions in Cu/Ni and the precipitation of intermetallic phases in Cu/Al. This study highlights the unique advantage of intermetallic strengthening in metallic multilayer systems.https://www.mdpi.com/2075-4701/14/3/256metallic multilayerCu/NiCu/Althermal strengtheningintermetallic strengthening
spellingShingle Yang Zhou
Junlan Wang
Mechanical Properties of Thermally Annealed Cu/Ni and Cu/Al Multilayer Thin Films: Solid Solution vs. Intermetallic Strengthening
Metals
metallic multilayer
Cu/Ni
Cu/Al
thermal strengthening
intermetallic strengthening
title Mechanical Properties of Thermally Annealed Cu/Ni and Cu/Al Multilayer Thin Films: Solid Solution vs. Intermetallic Strengthening
title_full Mechanical Properties of Thermally Annealed Cu/Ni and Cu/Al Multilayer Thin Films: Solid Solution vs. Intermetallic Strengthening
title_fullStr Mechanical Properties of Thermally Annealed Cu/Ni and Cu/Al Multilayer Thin Films: Solid Solution vs. Intermetallic Strengthening
title_full_unstemmed Mechanical Properties of Thermally Annealed Cu/Ni and Cu/Al Multilayer Thin Films: Solid Solution vs. Intermetallic Strengthening
title_short Mechanical Properties of Thermally Annealed Cu/Ni and Cu/Al Multilayer Thin Films: Solid Solution vs. Intermetallic Strengthening
title_sort mechanical properties of thermally annealed cu ni and cu al multilayer thin films solid solution vs intermetallic strengthening
topic metallic multilayer
Cu/Ni
Cu/Al
thermal strengthening
intermetallic strengthening
url https://www.mdpi.com/2075-4701/14/3/256
work_keys_str_mv AT yangzhou mechanicalpropertiesofthermallyannealedcuniandcualmultilayerthinfilmssolidsolutionvsintermetallicstrengthening
AT junlanwang mechanicalpropertiesofthermallyannealedcuniandcualmultilayerthinfilmssolidsolutionvsintermetallicstrengthening