Prediction of Fracture Behavior in a Quenching and Partitioning Steel Under Different Stress States

Increasing research efforts have been devoted to the development of quenching and partitioning (Q&P) steel, which is considered to be a very promising representative of the third generation of advanced high-strength steel (AHSS). The excellent tensile properties achieved by the novel Q&P treatment make it a potential material to manufacture structural components in automotive industries. In addition to tensile strength and ductility, the formability and fracture properties of Q&P steels shall be thoroughly investigated under different stress states. Therefore, the deformation and fracture properties of a laboratory Q&P steel have been investigated by conducting a comprehensive experimental program and the corresponding finite element simulations. Tensile tests have been performed using flat specimens with different notch configurations to achieve a very wide range of loading conditions. In addition, the deformation and fracture behavior during different experiments have been simulated using finite element methods and damage mechanics approaches. After collecting the critical stress and strain variables from simulation results, a stress state-dependent fracture criterion has been calibrated and validated to characterize the fracture resistance of the Q&P steel in this study.