MESOMECHANICAL SIMULATION OF CRACK PROPAGATION IN REAL AND QUASI-REAL IDEALIZED MICROSTRUCTURES OF TOOL STEELS

摘要

An innovative computational approach to the optimization of fracture resistance of two-phase materialsrnby varying their microstructure is suggested. The main points of the optimization of such materials are asrnfollows: (1) numerical simulation of crack initiation and growth in real microstructures of materials withrnthe use of multiphase finite elements (MPFE) and the element elimination technique [1-3], (2) simulationrnof crack growth in idealized quasi-real microstructures (net-like, band-like and random distributions ofrnthe primary carbides in the steels), (3) the comparison of fracture resistances of different microstructuresrnand (4) the development of recommendations to the improvement of the fracture toughness of steels.rnThree main mechanisms of increasing the fracture toughness of steels by varying the carbide distributionrn(crack deflection by normally oriented carbide layers, crack growth along the carbide network; crackrnbranching) are identified.