Flow stress evolution across the scales: From hardening mechanisms in fcc alloys to forming simulations of bcc steels
KU Leuven, Belgien
Department of Materials Engineering
The first part of this talk examines strain hardening mechanisms in face centered cubic based FeCoNiCr(Mn,Al) single and dual-phase high entropy alloys. Using selected single crystal orientations slip-slip, slip-twin, twin-slip and twin-twin interactions are triggered [1]. By incorporating them into a crystal plasticity framework their contribution to latent and self-hardening is quantified and correlated with dislocation reactions. The residual Burgers vector emerges as a central quantity to rationalize the experimental hardening/softening trends originating from twin-related dislocation reactions. In addition, secondary phases can largely increase hardening rates beyond those of single-phase microstructures [2].
The second part then presents ongoing experimental und numerical activities aiming to predict the mechanical properties of ferritic steel pipes manufactured from hot rolled coils. During pipe forming the coil material experiences a complex deformation history with several strain path changes leading to pipe properties differing from those of the coil. However, current phenomenological hardening models are not able to correctly reproduce the anisotropic strength evolution during forming [3]. Here in contrast, a physics-based crystal plasticity model incorporated into a computationally efficient hierarchical multi-scale forming simulation will be employed aiming to more accurately predict texture and strength changes. The current state of these efforts will be described and future developments discussed.
[1,2] M. Bönisch, Y. Wu, H. Sehitoglu, Acta Materialia 153 (2018) 391-403, Scientific Reports (2018) 8:10663
[3] S. Cooreman, D. van Hoecke, M. Liebeherr, P. Thibaux, M.Y. Enderlin, Proceedings of the 2016 11th International Pipeline Conference, Calgary, Canada
Matthias Bönisch, 18. June 2019