Investigating Ductile Failure at the Microscale in Engineering Steels: A Micromechanical Finite Element Model

In this study, we present a microstructure-based micromechanical model to quantify failure mechanisms in engineering steels. Crystal plasticity at the microscale, governed by crystallographic slip, is explicitly taken into account in the frame-work of continuum mechanics. Furthermore, it is assumed that material damage at the microscale is controlled by the accumulated equivalent plastic strain, such that failure occurs once this strain exceeds a threshold. Both single- and poly-crystalline materials containing sufficient numbers of grains are investigated under a representative macroscopic loading. The calibration of the present model relies on uniaxial tensile test data. Both austenitic stainless steels (such as 316H) and martensitic steels (such as P91) are examined to illustrate the application of the method. The micromechanical modelling provides insights into understanding of the mechanical response at the microscale in engineering steels.