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MM: Fachverband Metall- und Materialphysik

MM 18: Poster Session I

MM 18.13: Poster

Montag, 16. März 2020, 18:15–20:00, P4

On the complex structure and phase boundaries in Fe-Al binary alloys — •Subhamoy Char and Dasari Prasad — Department of Chemistry, Indian Institute of Technology Kanpur, UP-208016, India

Although elemental Fe and Al are simple metals in their respective ground states, the solubility of one in another with varying composition leads to a series of intermetallic Fe_xAl_y phases consists of wide variation in structure, electronic, magnetic, and mechanical properties. The phases are dressed-up with full of complexities that are often challenged the computations to comprehend the structure-property relationship. This is mostly attributed due to the fact that the structures undergo temperature driven order-disorder phase transformations, thermal vacancies, antisite defects, and ambiguous phase segregation between different Fe-Al phases. Therefore, it is indispensable to correctly model the phase diagram by predicting the Fe-Al structures at finite temperature. While the DFT is more effective in calculating total energies and forces of such alloys, it is computationally quite an arduous task in predicting the structures across the temperature verses the compositional structure state-space of Fe-Al phase diagram. Here, we have adopted a hybrid data-driven, stochastic and evolutionary crystal structure prediction approach coupled to DFT electronic energy calculations to predict thermodynamically viable structural solutions and thereby the Fe-Al phase boundaries are constructed. It is found that the vibrational entropy essentially steers the inexplicable phase segregations in Fe-Al binary alloys.