THE INFLUENCE OF A GLASSY PHASE ON THE HIGH-STRAIN RATE RESPONSE OF ACERAMIC

Results of pressure-shear plate impact experiments on an alumina ceram ic (AD85) containing a significant amount of an oxide glass phase are presented. Under high strain-rate loading, the ceramic shows low shear strength and a strong strain softening behavior. This behavior is att ributed to the response of the intergranular glassy phase. The ceramic is modeled by using an atomistic constitutive model for the response of the glass. This model utilizes the concept of free volume. Computat ions performed using this constitutive model predict a localization of the deformation near the impact end of the specimen and show that the increase in free volume that occurs in the glass during the deformati on is responsible for the observed softening response. Void compaction in the AD85 during the compressive loading is also modeled. (C) 1998 Elsevier Science Ltd. All rights reserved.