Breviary Technical Ceramics



 Bending Strength

The bending strength, [MPa], is the most important parameter for estimating the strength of components and for dimensioning them. Tables of materials properties contain values obtained from either 3-point or 4-point tests on special bending test bars. The value obtained from the 3-point bending test is around 30% higher than that from the 4-point test. In Germany it is usual to quote figures based on the 4-point procedure. Comparing the data is often made more difficult by the absence of information about the method used for the measurement.

The values for a component's bending strength are affected by the size, shape, surface ("as fired", ground etc.), and, in some cases, by inhomogeneities in the microstructure resulting from the manufacturing process.

Test procedures for determining the bending strength are defined in DIN EN 843-1, DIN EN 820-1 and DIN EN 60 672-2.

Figure 83: Bending strength of selected materials

Technical ceramics are distinguished by their very good high-temperature strength, with maximum working temperatures that even exceed those of metallic superalloys. Ceramic materials are thus ideal for applications in high-temperature processes (see Figure 84).

Figure 84: Effect of temperature on bending strength


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