Crack growth along interfaces in porous ceramic layers

Crack growth along porous ceramic layers was studied experimentally. Double cantilever beam sandwich specimens were loaded with pure bending moments t o obtain stable crack growth. The experiments were conducted in an environm ental scanning electron microscope enabling in situ observations of various mechanisms associated with crack growth. The macroscopic fracture energy o f the interface between dense lanthanum strontium chromite and a porous lan thanum strontium manganite was measured to lie in the range of 1.4-3.8 J/m( 2). Several micromechanisms were observed ahead of, or in the wake of, the crack tip. The measured variation of the fracture energy along the crack le ngth may be attributed to such phenomena.