Embrittlement of Ni-Ti-B glasses during crystallization

Abstract

The fracture response of NiTiB glasses has been studied as different heat treatments are given to induce different amounts of crystallinity. At the same time, the fracture surface morphology and crack and shear band interactions with crystals have been examined using electron microscopy. Crystals embedded in the glass matrix cause stress and strain concentrations which lead to crack or cavity nucleation. A fracture model is developed, based on such effects, and it is shown that different crystalline phases and distributions cause different degrees of cavity nucleation and growth.