Dislocation-Density Crystalline Plasticity Modelling of Lath Martensitic Microstructures in Steel Alloys

Tarek Hatem (1) , Mohammed Zikry (1)

1 Department of Mechanical and Aerospace Engineering [Raleigh]

A three-dimensional multiple-slip dislocation-density-based crystalline formulation, specialized finite-element formulations, and Voronoi tessellations adapted to martensitic orientations, were used to investigate large strain inelastic deformation modes and dislocation-density evolution in martensitic microstructures. The formulation is based on accounting for variant morphologies and orientations, retained austenite, and initial dislocations-densities that are uniquely inherent to martensitic microstructures. The effects of parent austenite orientation and retained austenite were also investigated for heterogeneous f.c.c./b.c.c. crystalline structures. Furthermore, the formulation was used to investigate microstructures mapped directly from SEM/EBSD images of martensitic steel alloys. The analysis indicates that variant morphology and orientations have a direct consequence on dislocation-density accumulation and inelastic localization in martensitic microstructures, and that lath directions, orientations, and arrangements are critical characteristics of high strength martensitic deformation and behaviour.

Mots clés: Physical Sciences

Tarek Hatem, Mohammed Zikry. Dislocation-Density Crystalline Plasticity Modelling of Lath Martensitic Microstructures in Steel Alloys. Philosophical Magazine, 2009, 89 (33), pp.3087-3109. ⟨10.1080/14786430903185999⟩. ⟨hal-00529578⟩