Reduced strength degradation of alumina-aluminium titanate composite subjected to low-velocity impact loading

The impact behaviour of monophase alumina and alumina-aluminium titanate monolithic composite ceramics that present flaw tolerant behaviour was studied. Low-velocity impact loading tests were performed on bending bars and the residual strength after the impact was evaluated by four-point bending tests. The impact tests were monitored using an instrumented drop-weight machine. During impact, the composites absorbed higher energy than the monophase material. The strength retention, in percentage, after the impact was significantly higher for the composite that presented damage tolerance for impact energy levels higher than monophase alumina. These results are discussed and fractographic analysis was used to identify the mechanisms responsible for the lower strength degradation of the composite.