Static and Dynamic Compressive Behavior of Aluminum Nitride under Moderate Confinement

An experimental technique for imposing lateral confinement on specimens subjected to dynamic or quasi-static uniaxial compression has been developed. Lateral confinement is provided by a shrink-fit metal sleeve installed on the lateral surface of a cylindrical ceramic specimen. Experiments using this technique were performed on sintered aluminum nitride (A1N). The results show that the failure mode changes from fragmentation by axial splitting under conditions of uniaxial stress to localized faulting under moderate lateral confinement. The compressive failure strength of the AlN increases with the increase of confinement pressure under both static and dynamic loading conditions. The effect of strain rate on the failure strength appears to be independent of the confinement pressure.