Fracture mechanics testing and crack growth simulation of highly ductile austenitic steel

The present contribution deals with ductile austenitic cast steel (Cr19Ni7Mn6Si0.3 steel). CT-specimens are cut out of cast plates and tested under monotonic and quasi-static conditions. Good ductility, high work hardening and restricted specimen dimensions complicate the fracture mechanical characterization of the material and regular fracture toughness values cannot be determined. Crack tip opening displacement (CTOD) and crack extension are measured optically. Force-displacement data and crack growth resistance curves have been gleaned from the experiments. A cohesive zone model has been utilized to simulate the fracture event (crack initiation and propagation). The results of these simulations have been compared with experimental data. The aim is to determine the cohesive parameters as these can be related to fracture toughness. The transferability of these parameters to specimens of greater thickness remains an open question.