Mechanical Properties of Pure, Dense Aluminum Oxide as a Function of Temperature and Grain Size

The elastic modulus and transverse bend strength of pure, dense alumina specimens were determined as a function of grain size (1 to 250μ) and temperature (30° to 1500°C). The elastic modulus was essentially independent of grain size over the temperature range covered. The transverse bend strength for fine–grain–sized alumina was substantially greater than that for larger–grain–sized alumina over the entire temperature range, although, at the highest temperatures, the rate of decrease of strength with temperature was greatest for the he–grained material. Fine–grained alumina (1 to 2P) exhibited considerable yielding and nonlinear load–deflection behavior at 1000°C and above. At 150O°C, the 1‐ to 2‐μ specimens bent to the limit of the apparatus without fracturing (approximately 7% outer‐fiber strain).