Multiscale Problems in Three Applications - Abstract
Kastner, Oliver
Martensitic transformations (MT) are a special class of diffusion-less solid-solid phase transitions which occur in metallic alloys. This contribution shows results obtained from large scale atomistic simulations of MT in unconstrained test assemblies in 2D. The model employs binary Lennard-Jones potentials, which are constructed so as to allow for lattice transformations between a symmetric austenite phase and variants of martensite. With this model atom dynamic (AD) simulations concerning test assemblies of up to 262,000 atoms were carried out. The test assemblies had different rectangular shapes (bar-like to square). Constraints to the surface were minimized or absent (free surface) in order to allow for free nucleations and evolutions of MT. The simulations were carried out in temperature control mode in order to simulate temperature induced transformations. The results highlight the spatial and temporal evolution of MT in some detail. Observed phenomena are - the propagation of traveling transformation fronts across a bar, - the martensitic plate growth in extended bulk material involving the twinning process, - the free formation and accommodation of martensitic grain structures exhibiting different orientations.