High damage tolerant Al₂O₃ composite ceramics constructed with short Al₂O₃ fibers

Abstract

The catastrophic fracture characteristics of ceramic materials have become one of the most serious factors limiting their application in critical areas, as a result, it is urgent to overcome the brittleness and improve the damage tolerance of ceramic materials. Herein, a series of Al2O3 composite ceramics developed with short Al2O3 fibers and a compound interface phase composed of Al2O3 and h‐BN powders, followed by investigating their fracture behaviors and damage tolerance. Results show that these composites present progressive fracture manners with the rising resistance curve (R‐curve) behaviors, and the maximum crack growth toughness of the sample with 15% compound interface phase reaches above 10 MPa·m1/2 (135% increase with respect to the reference alumina). Meanwhile, the composite ceramic exhibits an excellent ability to resist catastrophic failure with a large critical crack size (105.47 ± 19.11 μm) and high damage tolerance parameter (0.71 ± 0.06 m1/2), which are close to 14.57 times and 5.92 times higher than those of the reference alumina. The superior performances are mainly attributed to the precise combination of compound interface phase for inducing crack and interlocking Al2O3 fibers for load capacity.