Berlin 2015 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 42: Mechanical Properties I

MM 42.5: Vortrag

Mittwoch, 18. März 2015, 17:00–17:15, TC 010

Refined statistical work hardening and recovery model for Aluminium alloys — •Volker Mohles¹, Volker Pankoke¹, Philipp Schumacher², and Benjamin Milkereit² — ¹RWTH Aachen University, Institute of Physical Metallurgy and Metal Physics, Aachen, Germany — ²University of Rostock, Chair of Materials Science, Rostock, Germany

A new statistical work hardening and recovery model for aluminium alloys called 4IVM (4 Internal Variables Model) has been developed. Like its established predecessor (3IVM+) it calculates the evolution of dislocation densities during plastic deformation and derives the corresponding flow curves in a wide range of temperatures and strain rates. In order to improve the physical basis and its applicability, the new model considers four densities of dislocations as material state variables: mobile dislocations (ρ_mob), dipole dislocations (ρ_dip), locked dislocations (ρ_lock), and subgrain boundary dislocations (ρ_sub). These dislocation types have distinctly different properties, in reality and in the model, with respect to generation, annihilation, direct impact on the flow stress, and the overall dislocation density evolution. Moreover their cores and strain fields differ. In future this allows to introduce specific dependencies on segregation by foreign solved atoms. The new model is validated by comparing simulated flow curves to measured ones. For this, binary Al-Si alloys have been prepared and compression tested in varying precipitation states. Compared to its predecessor, 4IVM offers improved flow curve predictions.