Papers by Keyword: Fiber Reinforced Ceramics

Abstract: PSZ (ZrO₂ Fiber)-reinforced HAp was sintered using conventional and microwave hybrid heating. Microwave heating cycles were ~50 times faster than conventional sintering cycles and enabled the use of reduced densification temperatures and soak times by as much as ~100°C and 55 min, respectively. However, although there was a significant improvement in densification levels attainable before decomposition, the improvements were insufficient to produce near-fully or fully dense samples. However, the promising gains made suggest that microwave hot pressing would be a suitable area for future work. Keywords: Hydroxyapatite, microwave sintering, fibre-reinforced ceramics, bioceramics, zirconia fibre

Abstract: After fiber reinforced ceramics occur a crack, its bridging fibers must engender, moreover the crack usually runs in the format of similarity. In order to analyze easily dynamic problems of fiber reinforced ceramics, bridging fiber segment is substituted for loads. When a crack moves at high speed, its fibers will break continuously. By application of the built dynamic model and the ways of self-similar functions, analytical solutions of the displacements, stresses and dynamic stress intensity factors under the action of a running increasing force Px2/t2 and a motive unit step load, respectively, can be gained, and it is also used to attain the concrete solution by means of superposition theorem.

Abstract: In this paper, a numerical code, Realistic Failure Process Analysis code (RFPA), was used to perform a microscopic analysis of a crack in a fiber-reinforced ceramic, when the crack length is the same order of magnitude as the fiber spacing. The numerical results performed in the paper shown the failure process of fiber-reinforced ceramic subjected to tension loading, which indicate that the reinforcing fibers in a ceramic composite have a significant effect in inhibiting crack propagation even during the stages of the development of crack. Moreover, the fiber evidently increased the load-carrying capacity.

Abstract: Determination of the fracture toughness using a specimens with straight and/or chevron notch in the three (four) point bend test for monolithic ceramic materials can be taken as standardized techniques. In case of composite materials, mainly of brittle matrix reinforced by unidirectional fibres the crack growth resistance increases as the crack propagates. In addition, the long fibres stimulate delaminations along fibre – matrix interface perpendicularly to the major crack. Fracture toughness determination (in the loading mode I) in cases when delaminations take place is difficult. The chevron notch technique could be the right way to overcome this difficulty and obtain exact fracture toughness characteristics by its natural ability to “keep” the direction of major crack. Based on fractographic analyses some examples are described to show potential of the chevron notch technique for fracture resistance characterisation of the studied composite including comparison of data from chevron and straight notch technique etc.