How does crack deflection increase the energy absorbed by a ceramic?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

advanced structural ceramics Figure 1: Resistance to cracking in transformation-toughened zirconia. In a ceramic composed of tetragonal zirconia dispersed in a zirconia matrix, the stress field advancing ahead of a propagating crack transforms the small tetragonal particles to larger monoclinic particles. The larger particles exert a crack-closing force in the process zone behind the crack tip, effectively resisting propagation of the crack.

In the field of advanced structural ceramics, crack deflection is a key mechanism used to improve the material's fracture toughness.

When a ceramic is engineered with specific microstructures—such as fibrous or interlocked grains, or through the use of whiskers and fibres—the path of an advancing crack is forced to deviate from a straight line. This deflection leads to a dramatic increase in the total length of the crack. Because the crack must travel a longer path through the material, the fracture surface area increases significantly. This process requires more energy to propagate the crack, resulting in much greater overall energy absorption by the ceramic.1