Temperature and porosity dependence of the modulus of rigidity and Poisson's ratio of beryllia

Abstract

Using torsional equipment designed for the task, the modulus of rigidity of isostatically pressed and sintered beryllia was determined as a function of temperature and porosity. The temperature dependance was given by: Gt = G20 (1-at), where Gt is the modulus at toC, G20 is the modulus at 20oC and a is a constant approx. 3 x 10-5 degC independent of porosity up to 800oC. Porosity dependance was given by: Gt = Go (1-bP), where Go is the modulus at zero porosity, P is the fractional volume porosity and b is a constant approx. 1.58 independent of temperature up to 800oC. Poisson's ratio was found to be 0.30 + 0.05 and was independent of both temperature and porosity.