Detection of Crack Propagation in Alumina Using SrAl2O4:(Eu,Dy) Luminescent Paint

Using a mechano-luminescent (ML) paint enabling the visualization of fast propagating crack as well as bridging stress distribution under a conventional loading condition, this paper presents a catastrophic fracture mechanism in association with the crack wake bridging in alumina ceramics. The bridging stress distribution evolves in its magnitude and shape as crack advances and keeps changing as load changes even for a stationary crack. An instantaneous stress intensity factor skyrocketed extraordinarily up to 120 MPa√m, which is due to the well-known effect of specimen dimension and the accurate location of real crack tip by the ML technique.