Physicum seminar "Short range order in a high entropy alloy and its role in vacancy energetics and hydrogen trapping"

Klipi teostus: Nils Austa 13.10.2022 1555 vaatamist Füüsika ja astrofüüsika


Artur Tamm (UT Associate professor in computational physics)

High entropy alloys is a material class consisting of multiple principal elements in equal concentrations. Many different elements making up an alloy increase the importance of the configurational entropy which stabilises the single phase disordered phase. Widely varying local environments are beneficial for applications in extreme environments, such as high radiation and corrosive environments. Moreover, high entropy alloys show improved mechanical properties and can be designed by changing the consistency.
Cantor alloy is a prototypical material consisting of five metallic elements (NiCrCoFeMn) used for studying the general trends of high entropy alloys. One of the common assumptions is that the elements in the alloy are randomly distributed. Recent computational and experimental studies have observed short-range order in ternary and quaternary "medium" entropy alloys.
Our computational study investigates the chemical ordering in the Cantor alloy and its role on defect formation and hydrogen absorption. We analyse the short-range order in both the bulk material as well as in selected grain boundaries. Next, we computed the vacancy formation energies in both the random alloy as well as in the alloy with local ordering. Finally, we populated the vacancies with hydrogen atoms to investigate the trapping capability.

The Physicum seminars are meant for a broad auditorium of physicists and materials scientists, as well as for interested people from other natural and exact sciences (including bachelor level students) and aim at introducing what is important and new in a certain field, or where a specific research direction has reached today.

Seminar is in English. Everybody is welcome to attend.