The mechanical response of UFG and nanostructured microalloyed steels subjected to dynamic loading conditions

Abstract

As the number of available, advanced high-strength metallic materials possibilities increases due to advancements in processing (for example advanced thermomechanical processing - ATP or severe plastic deformation - SPD), experimental comparisons alone are not sufficient for determination of the most ideal microstructures for specific applications. Our study deals with the dynamic behaviour of high strength steels and in particular with ultrafine-grained (UFG) microalloyed ferrite and austenite. The forming processes of modern UFG materials require rheological models describing the materials behaviour at large strains and strain rates up to over 1000 s-1. In our case, the mechanical response of UFG steels (produced using MaxStrain system) was investigated with split Hopkinson pressure bar (SHPB) tests, performed at room temperature. The dynamic work-hardening behaviour as a function of solute atoms and fine-scale, secondphase particles in the nano-structures of microalloyed ferrite and austenite has been compared to the mechanical response of these materials under quasi-static loading conditions.