Elastic Properties of Polycrystalline Aluminum Oxynitride Spinel and Their Dependence on Pressure, Temperature, and Composition

Abstract

The isotropic elastic moduli of four specimens of nitrogen‐stabilized cubic aluminum oxide (ALON) were measured using pulse superposition interferometry. Experiments were carried out as a function of both pressure (ambient to 1 GPa) and temperature (0° to 25°C) for specimens of 30.0 and 35.7 mol% AlN. The second‐order moduli results were corrected for porosity using the “self‐consistent‐scheme” approach. Pertinent ambient results for isotropic pore‐free ALON are K = 226.3 GPa and G = 132.0 GPa for the 30.0 mol% AlN material, and K = 229.8 GPa and G = 135.5 GPa for 35.7 mol% ALON ( K and G denote the bulk and shear moduli, respectively). The estimated uncertainties in these values are about 2%. The second‐order elastic properties of ALON, as well as their pressure and temperature derivatives, fall midway between spinel (MgAl 2 O 4 ) and corundum (Al 2 O 3 ), indicating the excellent potential of this material for structural engineering purposes.