An experimental and microstructural investigation of biaxial Bauschinger effects in IF steel DC06 using in-situ neutron diffractionTuesday (27.09.2016) 15:30 - 15:45 Part of:
Classically, the Bauschinger effect refers to a reduction of yield strength after a load path change under uniaxial loading. In this study, we present first results of an experimental investigation on Bauschinger effects in the sheet metal DC06 subjected to in-plane biaxial loading: We first performed biaxial tensile tests with cruciform specimens up to different pre-strains. Then, smaller specimens were prepared from the biaxially deformed inner part of the cruciform specimens. With these smaller specimens, we performed biaxial compression tests in a newly developed test-rig. The material exhibits distinct Bauschinger effects when subjected to biaxial load path changes, which result in different mechanical properties compared to the behavior under uniaxial load. We discuss how these novel Bauschinger effects can be rationalized by considering the results of TEM and EBSD investigations at the different stages of biaxial loading. Furthermore, residual stress measurements by in-situ neutron diffraction were performed. After the biaxial tensile deformation, compressive residual stresses can be detected; these residual stresses facilitate yielding under biaxial compression and clearly affect the observed Bauschinger effects.