Dynamic Compressive Fracture of Ceramic Polymer Layered Composites

Dynamic compressive fracture evaluation is an essential characterization technique for advanced monolithic structural ceramics like alumina. Thus, for high strain rate induced damage tolerant applications, it is needed to take care of the characteristically brittle microstructure of the alumina ceramics. Hence, a smarter design concept has been involved based on the idea that cracks can either be arrested or deflected if a weak interface or interphase can be introduced. Thus, ceramic polymer layered composites (CPLC) were fabricated from high (e.g., 97%) density alumina disks pressureless sintered from sub-micron (d50-0.6 □m) alumina powder. The dynamic fragmentation of the CPLC samples at a reasonably high e.g., 900.s-1 strain rate has been studied with the real time, high-speed, in-situ video images, obtained during their failure in SHPB tests. A new failure mechanism has been proposed based on these data and FESEM evidences of grain boundary microcrack, inter/intra-granular shear bands and micro-fracture/cleavage formation.