EXPERIMENTAL-STUDY OF THE FRACTURE-TOUGHNESS OF A CERAMIC CERAMIC-MATRIX COMPOSITE SANDWICH STRUCTURE/

A hybrid experimental-numerical approach has been used to measure the fracture resistance of a sandwich structure consisting of a 304 stainl ess steel/partially stabilized zirconia ceramic-matrix composite crack -arresting layer embedded in a partially stabilized zirconia ceramic s pecimen. The mode I fracture toughness increases significantly when th e crack propagates from the ceramic into the ceramic-matrix composite region. The increased toughening due to the stainless steel particles is explained reasonably well by a toughening model based on processing -induced thermal residual stresses. In addition, several experimental modifications were made to the chevron-notch wedge-loaded double canti lever beam specimen to overcome numerous problems encountered in gener ating a precrack in the small, brittle specimens used in this study.