Anisotropy of fracture toughness in nanostructured ceramics controlled by grain boundary design
| Autor: | Walter Baumegger, Christian Mitterer, Jakub Zalesak, Rostislav Daniel, Jozef Keckes, Juraj Todt, Tobias Ziegelwanger, Michael Meindlhumer |
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| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
Materials science
Mechanical Engineering Fracture mechanics Cleavage (crystal) 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Nanocrystalline material 0104 chemical sciences Fracture toughness Mechanics of Materials visual_art visual_art.visual_art_medium lcsh:TA401-492 General Materials Science Grain boundary lcsh:Materials of engineering and construction. Mechanics of materials Texture (crystalline) Ceramic Composite material 0210 nano-technology Anisotropy |
| Zdroj: | Materials & Design, Vol 161, Iss, Pp 80-85 (2019) |
| ISSN: | 0264-1275 |
| Popis: | The fracture toughness of nanostructured materials depends on anisotropic physical properties of individual microstructural features, their texture and/or topology. In this work, intentionally sculptured grain boundaries of low cohesive energy were used to form “weak” and “tough” crack propagation directions within a nanocrystalline TiN film, allowing to correlate the directional arrangement of grains and anisotropy of fracture toughness. By using a selective micromechanical testing approach, two different cracking directions were probed in a scanning electron microscope by loading microcantilever beam specimens prepared parallel and perpendicular to the stacked direction of the alternately tilted columnar grains. The fracture toughness along the sculptured grain boundaries was ~30% higher due to effective multiple crack deflection at the kink planes, which was not observed along weak cleavage planes in the stacked direction. The results indicate the fundamental importance of microstructural design in the synthesis of tough nanostructured ceramics, whose anisotropic mechanical properties can be controlled effectively by incorporating dedicated microstructural features of well-defined topology, orientation and density. Keywords: Nanostructured hierarchical materials, Microstructure design, Enhanced fracture toughness, Micromechanical testing, Grain boundary design |
| Databáze: | OpenAIRE |
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