In situ micromechanical analysis of a nano-crystalline W-Cu composite

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Abstract

W-Cu composites are commonly used as heat-sinks or high-performance switches in power electronics. To enhance their mechanical properties and mutually their usability, grain refinement of the initially coarse-grained microstructure was realized using high–pressure torsion. This leads to different microstructural conditions, exhibiting fine-, ultrafine-grained or nanocrystalline microstructures. Scanning as well as transmission electron microscopy was performed to analyze the respective grain size and microstructures. The hardness and Young’s modulus of the deformed specimens were quantified by nanoindentation testing. Furthermore, X–ray diffraction indicated a decreased grain size and changed lattice spacings upon increasing the deformation ratio. The deformed specimens were tested for their fracture behaviour by continuous stiffness measurements during in-situ microcantilever bending experiments. Here, mean J–integral values of 288 ± 38 J/m2 and 402 ± 89 J/m2 were determined for the 5 and 50 times turned specimens, respectively. The combination of different characterization methods applied on a W–Cu composite allows to identify both, beneficial and unfavourable microstructural components regarding the fracture properties.
OriginalspracheEnglisch
Aufsatznummer110848
Seitenumfang9
FachzeitschriftMaterials and Design
Jahrgang220.2022
AusgabenummerAugust
DOIs
PublikationsstatusVeröffentlicht - Aug. 2022

Bibliographische Notiz

Funding Information:
The authors gratefully acknowledge the financial support of the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (Grant No. 771146 TOUGHIT). The financial support by the Austrian Federal Ministry for Digital and Economic Affairs and the National Foundation for Research, Technology and Development is gratefully acknowledged. Furthermore, the authors thank Gabriele Felber and Ing. Herwig Felber for supporting the TEM specimen preparation as well as for technical assistance and advice. We also acknowledge Dipl.-Ing. Caroline Freitag for SEM specimen preparation and Dr.mont. Wolfram Knabl from Plansee AG, Austria for supplying the undeformed W–Cu rod material.

Funding Information:
The authors gratefully acknowledge the financial support of the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (Grant No. 771146 TOUGHIT). The financial support by the Austrian Federal Ministry for Digital and Economic Affairs and the National Foundation for Research, Technology and Development is gratefully acknowledged.

Publisher Copyright:
© 2022 The Authors

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