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Regensburg 2013 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 15: Poster Session

MM 15.41: Poster

Montag, 11. März 2013, 18:00–20:00, Poster E

First-principles calculations and kinetic Monte Carlo simulations of screw dislocation motion in dilute W alloys — •Leili Gharaee1, Alexander Stukowski2, Jaime Marian3, and Paul Erhart11Chalmers University of Technology, Gothenburg, Sweden — 2Technische Universität Darmstadt, Darmstadt, Germany — 3Lawrence Livermore National Laboratory, Livermore, California

Tungsten is being considered as a candidate material for structural applications in fusion reactors. The performance of the pure material is, however, limited by a high ductile-to-brittle transition temperature (DBTT), which can be lowered by alloying for example with small amounts of Re. These alloys are, however, not suitable for applications in fusion environments due to neutron activation of Re, which motivates the search for alternative alloys. The present work addresses the potential of dilute W-Ti alloys to accomplish a lowering of the DBTT. To this end, we have studied the elastic properties of intrinsic defects and substitutional alloying agents in body-centered cubic tungsten as well as their direct interaction with screw dislocations using density functional theory. In this fashion we determined deformation volume tensors and interaction strenghts for each of these entities. The thus obtained information was subsequently employed to parametrize a kinetic Monte Carlo model for screw dislocation motion that takes into account the elastic interaction between dislocation segments and point defects. This approach enabled us to study systematically the effect of various defects on the mobility of screw dislocations as a function of shear, temperature, and defect density.

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