Fracture toughness of flake graphite cast iron

Abstract

Fracture-toughness tests have been carried out on flake graphite cast irons having a range of eutectic cell sizes and different matrix microstructures. Provided that tension geometries are employed, the toughness can be characterized by a critical stress intensity factor. In bend specimens the toughness is overestimated because of differences in elastic modulus in the tensile and compressive regions of the specimen. Both the fracture toughness and the tensile strength increase with decreasing cell size and increasing matrix hardness.