Microstructure and flexural properties of multilayered fiber-reinforced oxide composites fabricated by a novel lamination route

All-oxide ceramic matrix composites produced by a novel route based on the lamination of thermoplastic prepregs are investigated. This route allows for the production of composites with very homogeneous microstructures and a reduced amount of matrix cracks. NextelTM 610 alumina woven fabric is used here to reinforce a porous oxide matrix composed of 80 vol% Al2O3 and 20 vol% ZrO2. The mechanical behavior of composites submitted to different heat treatments is investigated under 4-point bending and short beam shear. Results show that composites with low interlaminar shear strength present a graceful failure under 4-point bending, characterized by a stepwise stress reduction upon straining beyond the peak stress. The fracture of such composites is accompanied by a series of interfacial delamination events, which enhance energy dissipation during failure. An increase of the interlaminar shear strength due to matrix densification causes a loss of the stepped stress-strain behavior. Nevertheless, fiber-related toughening mechanisms such as crack deflection and bridging still ensure inelastic deformation up to failure of these composites.

Subjects

alumina

ceramic matrix composites

lamination

thermoplastic prepregs

zirconia

DDC Class

600: Technik

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Microstructure and flexural properties of multilayered fiber-reinforced oxide composites fabricated by a novel lamination route