STATIC AND DYNAMIC COMPRESSIVE BEHAVIOR OF ALUMINUM NITRIDE UNDER MODERATE CONFINEMENT

An experimental technique for imposing lateral confinement on specimen s subjected to dynamic or quasi-static uniaxial compression has been d eveloped. Lateral confinement is provided by a shrink-fit metal sleeve installed on the lateral surface of a cylindrical ceramic specimen. E xperiments using this technique were performed on sintered aluminum ni tride (AIN). The results show that the failure mode changes from fragm entation by axial splitting under conditions of uniaxial stress to loc alized faulting under moderate lateral confinement. The compressive fa ilure strength of the AIN increases with the increase of confinement p ressure under both static and dynamic loading conditions. The effect o f strain rate on the failure strength appears to be independent of the confinement pressure.