Quantitative Prediction of Cleavage Fracture Toughness of Ferrite Steel without Adjustable Parameters

AbstractThis study presents a numerical model to quantitatively predict a cleavage fracture toughness of ferrite-cementite steel without any adjustable parameters. The model is constructed in framework of multiscale analysis. The macroscopic analysis is an elasto- plastic finite element analysis. A microscopic analysis is based on the Monte Carlo method considering microscopic fracture process of the three stages; Stage-I: formation of fracture origin by cementite cracking, Stage-II: propagation of the cementite crack into ferrite matrix and formation of a cleavage crack, and Stage-III: propagation of the cleavage crack across ferrite grain boundary. The predicted results of fracture toughness show good agreement with the experimental results including their scatter. Influences of microstructures on fracture toughness can be estimated by parameter studies. According to the results, the validation and the effectiveness of the proposed model are found out