habraste materjalide sitkenemismehhanism, mida iseloomustab prao avanemine ja seeläbi leviku takistamine; mehhanism on iseloomulik tehno- ja klaaskeraamikale, mis on armeeritud kiududega, niitkristallidega, liistakutega, samuti plastsest metallist osakestega, a feature of the microstructure that extends across a crack behind the crack tip and imposes a closing force on the crack; it is a major toughening mechanism for ceramics reinforced with long fibers