ICAMS / Interdisciplinary Centre for Advanced Materials Simulation
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Atomistic simulations of solid-solid phase transformations in molybdenum

Date: 01.04.2014
Time: 12:00 p.m.
Place: DPG Spring Meeting 2014, Dresden, Germany

Ari Harjunmaa
Jutta Rogal
Ralf Drautz
Rye Terrel, Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, USA
Sam Chill
Graeme Henkelman, Department of Chemistry and Biochemistry, The University of Texas at Austin, Austin, USA

As a refractory metal, molybdenum plays an important role in strengthening special-purpose materials such as Ni-base superalloys. In heavy usage, these materials are frequently plagued by the formation of topologically close-packed (TCP) phases, which concentrate the alloying atoms into brittle precipitates, rendering the material weaker. To find a way to prevent this detrimental occurrence, it is important to understand the atomistic processes at work in solid-solid phase transformations leading to the formation of TCP phases. As a first step, we investigate interfaces between the TCP A15 and the cubic BCC phases in molybdenum, using classical molecular dynamics to model the time evolution of the systems in question. We then compare and expand these results with those obtained from adaptive kinetic Monte Carlo simulations, extending the same system setup to room temperature; furthermore, we use this latter method to characterize singular processes involved in the transformation of the atomic layers. Finally, we evaluate the reliability of the employed empirical potential by further analysis of the main results using density functional theory.

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