Ceramic stress-strain diagram

Figure 5.115 Stress-strain diagrams for lithiumaluminosilicate glass ceramic reinforced with 50% SiC fibers in various orientations. From Ceramic Microstructures, by W. E. Lee and W. M. Rainforth, p. 103. Copyright 1994 by William E. Lee and W. Mark Rainforth, with kind permission of Kluwer Academic Publishers.

Engineering materials are generally referred to as metallic and nonmetallic (ceramics and high pol5nners) materials, which are further classified as ductile or brittle. As shown in the stress-strain diagram in Figure 1.1, the strain of ductile materials is 100-1000 times larger than that of brittle materials. The... 

Fig. 9.10. Schematic stress-strain diagram of a fibre-reinforced ceramic (after [29])...

Figure 9.10 schematically shows the stress-strain diagram of a ceramic matrix composite. First cracks in the matrix occur at a stress of [Pg.311]

The ceramics are materials that demonstrate brittle fractxxre, this means presenting only elastic stress behavior. Stress-strain diagram is therefore a straight line whose slope is Young s modulus of the material. The temperature dependence of the stress-strain diagram is therefore related to the dependence of Young s modulus. 

This competition between mechanisms is conveniently summarised on Deformation Mechanism Diagrams (Figs. 19.5 and 19.6). They show the range of stress and temperature (Fig. 19.5) or of strain-rate and stress (Fig. 19.6) in which we expect to find each sort of creep (they also show where plastic yielding occurs, and where deformation is simply elastic). Diagrams like these are available for many metals and ceramics, and are a useful summary of creep behaviour, helpful in selecting a material for high-temperature applications. 

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