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MM: Fachverband Metall- und Materialphysik

MM 39: Structural Materials (Steels, light-weight materials, high-temperature materials)

MM 39.8: Vortrag

Donnerstag, 4. April 2019, 17:30–17:45, H45

The surface and interface structures in nanofiber-reinforced ceramic matrix composites — •Yanhui Zhang and Stefano Sanvito — School of Physics and CRANN, Trinity College Dublin, Dublin, Ireland

Surfaces and interfaces are active sites for chemical reactions, stress/strain concentration and defect accumulation. Efficiently engineering them is critical for the R&D of novel composites in the industry sectors of aerospace, automotive and energy & power. Interfacial parameters are often inaccessible by experimental measurements due to the nano-scale of interface regions. Given the importance of surface morphology on the interface adhesion and mechanical responses, we firstly examine by first-principles thermodynamics the stable surfaces of the promising ceramic matrix materials TiB2, ZrB2 and HfB2. Thereafter, we took at one specific ceramic matrix composite, namely graphene-reinforced ZrB2, to systematically explore the structural, energetic and mechanical characters of heterophase interfaces. We demonstrate that the surface chemistry of the ZrB2 matrix material largely shapes the interface structures (Zr-C-Zr or B-C-B) and the nature of the interfacial interactions. Interestingly, the mechanical responses of strong Zr-C-Zr interfaces are significantly influenced by the corrugation of graphene; while the B-C-B interfaces with relatively weak pi-pi stacking show similar attributes as the 2D materials during interfacial cleavage and slip. Those results provide insights into the interface bonding mechanisms in graphene/ceramic composites, and emphasize the prospect of interface engineering via surface chemistry.