Elastic moduli of single crystal and polycrystalline MgO

Abstract

The elastic moduli of both single crystal and polycrystalline magnesia were determined in the kcps frequency range by a Forster-type resonance method. The values obtained at 25°C for single crystal are: c ₁₁ = 28•92c ₁₂ = 8•79 and c ₄₄ = 15•46 × 10¹¹ dynes per cm². The calculated isotropic elastic moduli for polycrystalline MgO obtained from the single crystal compliances are in good agreement with experimental values measured on theoretical density (glass-free) MgO. The measured Young's modulus and shear modulus at zero per cent porosity are 30•50 and 12•90 × 10¹¹ dynes per cm², respectively. The results of the present work are compared with the earlier work in the mcps frequency range.