Texture development and formability prediction for pre-textured cold rolled body-centred cubic steel

In this study, a polycrystalline material model is introduced. It consists of an artificial grain structure, where the individual crystal geometries are generated by Voronoi cells. In the grains slip planes and sliding directions, corresponding to the slip systems of bcc crystals, are incorporated. The crystallographic behaviour is captured in a consistent continuum mechanics based crystal plasticity framework based on the elastoplastic multiplicative split of the deformation gradient and a viscoplastic regularisation due to a constitutive relation of slip rates and the critical shear stress in the slip systems. A suitable flow rule fulfils the requirement of plastic incompressibility.The specific material considered is the ferritic steel DC04 (material number 1.0338). Based on the results of experimental studies, the initial texture is transferred via Euler angles into the modelled polycrystalline structure. For the determination of initial data as well as the validation of the material behaviour EBSD investigations are carried out. The comparison of the results is done by measuring the strain evolution of grains, the texture and the Schmid factor under uniaxial tensile load. In addition to EBSD measurements of pre-deformed material, in situ EBSD tensile tests are carried out in the SEM. The results of the in situ studies coincide with the results of the pre-deformed material. It is shown that the simulation results agree very well with the experimentally obtained data. The plastic material behaviour is reproduced very well by the simulation, whereas the texture and Schmid factor development shows a good correlation between model and experiment.