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MM: Fachverband Metall- und Materialphysik

MM 53: Topical Session: Fundamentals of Fracture - Novel Experimental Techniques II

MM 53.4: Vortrag

Donnerstag, 14. März 2013, 12:30–12:45, H4

The Effect of Prior Heat Treatment on the Fracture Energy of Metal Fibre Reinforced Ceramic Composites (MFCs) — •Su Ki Lam, Louise Gale, and Bill Clyne — Department of Materials, Pembroke Street, Cambridge CB2 3QZ UK

This work concerns the fracture energy of alumina matrix composites with (~15vol%) steel fibres. A recent model [1] gives the work of fracture from pull-out and/or plastic deformation of fibres bridging the crack plane. The present work concerns exposure to high temperature (~1,000C). The standard fibre is 304, with strength and ductility that confer toughness on the composite, mainly from fibre plasticity. However, this steel has poor oxidation resistance. Since the matrix offers little environmental protection, this oxidation can be extensive, reducing ductility and creating defects within the composite. The toughness can thus fall sharply after heat treatment. The study also covers another steel (310) with superior oxidation resistance. Fibres of 310 exhibit lower strength and ductility than 304 (as-received), but are less prone to oxidation-induced degradation of these properties. The fracture energy after heat treatment can thus be higher with 310 fibre, and fracture energy values are consistent with model predictions and experimental single fibre tensile data. Results are also presented concerning oxidation and microstructural changes. [1] S.R. Pemberton, E.K. Oberg, J. Dean, D. Tsarouchas, A.E. Markaki, L. Marston & T.W. Clyne, The fracture energy of metal fibre reinforced ceramic composites (MFCs), Composites Science and Technology, vol.71 (2011) p.266-275.