Research Progress on Fracture Toughness Testing Technology of Ductile Cast Iron

Fracture toughness is an important fracture resistance index of materials. The research status of plane strain fracture toughness, elastoplastic fracture toughness, crack tip opening displacement and dynamic fracture toughness testing techniques and their application to ductile cast iron materials are summarized. The influence of the temperature, microstructure and sample size on the fracture toughness of ductile cast iron is described. The problem of crack length testing in the fracture toughness specimen of ductile cast iron is discussed. The test method of fracture toughness of ductile cast iron based on J-Q (J integral-triaxial stress factor) theory is also described. It is believed that the multi-parameter fracture toughness testing based on the J-Q theory is the focus of future research. Furthermore, if the fracture toughness is to be used for engineering safety assessment, the loading mode and environment in actual service must be comprehensively considered during the testing.