Dresden 2020 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 54: Topical Session: Interface-dominated phenomena - Crystallization and Microstructure Evolution

MM 54.1: Talk

Thursday, March 19, 2020, 11:45–12:00, IFW A

Atomistic investigation of phase boundary migration during solid-solid phase transformations in tungsten — •Yanyan Liang, Grisell Díaz Leines, Jutta Rogal, and Ralf Drautz — Interdisciplinary Centre for Advanced Materials Simulation, Ruhr-Universität Bochum

The phase transformation between the topological close packed A15 and cubic BCC in the transition metal tungsten has recently incited attention, given the applications in microelectronics and spintronic devices where either BCC or A15 is favourable. The underlying atomistic processes greatly influence the kinetics of phase transformations, specifically the mobility and corresponding growth velocity of interfaces. At high temperatures, phase boundary migration can be captured by conventional molecular dynamics (MD) simulations. At moderate temperatures, however, enhanced sampling techniques are required due to the slow movement of the interface and corresponding extended timescales that need to be covered. We combine both, high-temperature MD and low-temperature enhanced sampling, to investigate phase boundary migration between A15 and BCC in W. From these simulations, we extract information concerning the growth mode, such as step nucleation and growth along the step edges or island formations. Furthermore, we investigate the influence of driving forces on interface migration at different mismatches between A15 and BCC. Together with the evaluation of energy barriers connected to the migration of the phase boundary, we provide novel insight into the atomistic mechanism and kinetics during the solid-solid phase transformation.