Effect of microstructure on the relationship between fracture toughness and ductility

The relationship between fracture toughness, expressed as JIC, and ductility, given by measurements of the bulge ductility, was studied experimentally for two microstructures of 1045 steel. These microstructures consist of annealed pearlitic structure with hardness Rc = 15 and a tempered matensitic structure with Rc = 23. JIC and bulge ductility measurements were performed in the temperature range of −100-25°C. The tensile properties at these …