Microstructure-based finite-difference analysis of the plastic flow in low-carbon steel

Abstract

Despite extensive research, the question – what makes the fronts of plastic strain (e.g. Lüders bands) propagate or remain still has not been solved yet. Therefore, the problem is acute for modern solid mechanics and physics. In this paper, an analysis of low-carbon steel plastic flow is carried out both numerically and experimentally. A microstructure-based finite-difference analysis is employed to provide a deeper insight into the emerging features of plastic flow. Low-carbon polycrystalline steel is chosen as the basic material for this investigation. A hand-controlled iterative procedure based on the step-by-step packing method is utilized to design a representative volume element (RVE) of the low-carbon steel under study. The designed model represents a cluster of grains randomly distributed within the computational domain according to a certain law and randomly oriented with respect to the global coordinate system based on the results of EBSD study. A number of earlier reported models of plastic flow are combined and modified to study the yield plateau stage of the model samples. The mathematical model parameters are accurately calibrated against the experimental data using quite simple methods. The results of modeling satisfactorily meet the available experimental data and sufficiently complement them in terms of reproducing some regularities of plastic flow observed both at micro- and macrolevel. Relying on the numerical modeling data the conditions at the front of the Lüders bands are discussed, which shed light on a possible mechanism of propagation.