Modeling of grain refinement and mechanical response of microalloyed steel wires severely deformed by combined forming process

Recently developed accumulative angular drawing (AAD) combined with wire drawing (WD) and wire flattening (WF) processes were employed to effectively induce severe plastic deformation (SPD) effects into drawn wires. The influence of combined effects of area reduction, bending, shearing, and burnishing on the accumulated deformation energy and microstructural inhomogeneities in the microalloyed steel (b.c.c.) wires has been discussed with respect to possibilities of formation of ultrafine-grained and multilayered structures in subsequently drawn and flattened wires. However, the main challenge in the present study was to support and extend experimental research on hardening mechanisms and inhomogeneous deformation energy accumulation during investigated combined forming process by numerical simulation. One of the efficient solutions to that task is development of multiscale numerical model based on digital material representation (DMR) concept, capable of explicit recreation of microstructure morphology of investigated materials as well as its further evolution with respect to complex macroscopic processing conditions. As an outcome, it was demonstrated that the presence of precipitates in the severally deformed and inhomogeneous ferrite can be not only the key factor in strengthening process but can also directly influence the grain refining process. The presented study provides a set of evidence and inspiration for introducing the controlled inhomogeneity of deformation as a tool to produce advanced structural materials.