Properties of iron after large and severe plastic deformation – Application potential for precursors to ultrafine grained microstructuresWednesday (26.09.2018) 12:00 - 12:15 S1/01 - A3 Part of:
Ultrafine grained (UFG) metals processed by severe plastic deformation are well known for their outstanding mechanical properties, yet, current applications are very limited mostly due to the elaborate processing. The present work investigates the microstructures and mechanical properties of precursors to UFG microstructures that evolve at strains below the levels required for UFG microstructures, which implies less processing effort. ARMCO® iron is subjected to a single pass of equal channel angular pressing (ECAP), cold rolling, as well as a combination of both processes and compared to strain–free samples and a UFG reference condition subjected to five ECAP passes. EBSD analyses show that the precursor states consist of a majority of low angle boundaries with a boundary spacing below 1µm. The mechanical properties from tensile tests and high cycle fatigue tests show intermediate properties for the precursor states in between those of the strain–free and the UFG reference condition. Compared to the processing effort, the difference in properties between precursors and UFG reference turns out to be relatively small. Especially a combination of a single ECAP pass followed by cold rolling is a good compromise in terms of processing effort and mechanical properties with an endurance limit being less than 10 % lower as compared to the UFG reference condition.