Effective pair potential for random fcc CoCrFeMnNi alloys

0531957 - ÚFM 2021 RIV GB eng J - Journal Article
Gröger, Roman - Vítek, V. - Dlouhý, Antonín
Effective pair potential for random fcc CoCrFeMnNi alloys.
Modelling and Simulation in Materials Science and Engineering. Roč. 28, č. 7 (2020), s. 1-25, č. článku 075006. ISSN 0965-0393. E-ISSN 1361-651X
R&D Projects: GA MŠMT(CZ) LQ1601
Institutional support: RVO:68081723
Keywords : pair potential * high entropy alloy * compositional randomness * CoCrFeMnNi * stacking fault * dislocation
OECD category: Condensed matter physics (including formerly solid state physics, supercond.)
Impact factor: 2.248, year: 2020
Method of publishing: Limited access
https://iopscience.iop.org/article/10.1088/1361-651X/ab7f8b

The single-phase equiatomic CoCrFeMnNi alloy is a random solid solution of five elements on the face-centered cubic lattice, whose pure constituents crystallize in very different structures and exhibit diverse magnetic properties. Due to the randomness of the alloy, 80% of nearest neighbor bonds are between unlike elements and thus the details of bonding in pure structures are less important. The elastic moduli of this alloy give rise to small Cauchy pressure C12−C44, which suggests that the dominant part of bonding may be described by a simple pair potential. We test this hypothesis by developing a long-range Lennard-Jones potential in which the equilibrium crystal structures of pure constituents are taken as reference. The standard mixing rules for regular solutions are then adopted to obtain parameters for bonds between unlike elements in the quinary system. The transferability of this potential to quaternary CoCrFeNi, ternary CoCrNi, and binary FeNi alloys is investigated and the predictions compared with experiments and density functional theory calculations. By sampling over a large number of random configurations, we investigate the effect of compositional randomness on misfit volumes, energies of point defects and stacking faults, and the dislocation friction stresses experienced by moving edge and screw dislocations.

Permanent Link: http://hdl.handle.net/11104/0311459