Predicting Fracture Toughness of TRIP 800 Using Phase Properties Characterized by In-Situ High-Energy X-Ray Diffraction

Transformation-induced plasticity (TRIP) steel is a typical representative of first generation advanced high-strength steel, which exhibits a combination of high strength and excellent ductility due to its multiphase microstructure. In this article, we study the crack propagation behavior and fracture resistance of a TRIP 800 steel using a microstructure-based finite element method with the various phase properties characterized by in-situ high-energy X-ray diffraction (HEXRD) technique. Uniaxial tensile tests on the notched TRIP 800 sheet specimens were also conducted, and the experimentally measured tensile properties and R curves (resistance curves) were used to calibrate the modeling parameters and to validate the overall modeling results. The comparison between the simulated and experimentally measured results suggests that the micromechanics based modeling procedure can well capture the overall complex crack propagation behaviors and the fracture resistance of TRIP steels. The methodology adopted here may be used to estimate the fracture resistance of various multiphase materials.