Understanding the physical metallurgy of the CoCrFeMnNi high-entropy alloy: An atomistic simulation study

Won Mi Choi, Yong Hee Jo, Seok S Sohn, Sunghak Lee, Byeong Joo Lee

Research output: Contribution to journalArticle

24 Citations (Scopus)

Abstract

Although high-entropy alloys (HEAs) are attracting interest, the physical metallurgical mechanisms related to their properties have mostly not been clarified, and this limits wider industrial applications, in addition to the high alloy costs. We clarify the physical metallurgical reasons for the materials phenomena (sluggish diffusion and micro-twining at cryogenic temperatures) and investigate the effect of individual elements on solid solution hardening for the equiatomic CoCrFeMnNi HEA based on atomistic simulations (Monte Carlo, molecular dynamics and molecular statics). A significant number of stable vacant lattice sites with high migration energy barriers exists and is thought to cause the sluggish diffusion. We predict that the hexagonal close-packed (hcp) structure is more stable than the face-centered cubic (fcc) structure at 0 K, which we propose as the fundamental reason for the micro-twinning at cryogenic temperatures. The alloying effect on the critical resolved shear stress (CRSS) is well predicted by the atomistic simulation, used for a design of non-equiatomic fcc HEAs with improved strength, and is experimentally verified. This study demonstrates the applicability of the proposed atomistic approach combined with a thermodynamic calculation technique to a computational design of advanced HEAs.

Original languageEnglish
Article number1
Journalnpj Computational Materials
Volume4
Issue number1
DOIs
Publication statusPublished - 2018 Dec 1
Externally publishedYes

Fingerprint

Atomistic Simulation
Metallurgy
Entropy
Simulation Study
Cryogenics
Face
Twinning
Energy barriers
Industrial Application
Hardening
Shear Stress
Alloying
Molecular Dynamics
Hexagon
Industrial applications
Migration
Molecular dynamics
Shear stress
Solid solutions
Thermodynamics

ASJC Scopus subject areas

  • Modelling and Simulation
  • Materials Science(all)
  • Mechanics of Materials
  • Computer Science Applications

Cite this

Understanding the physical metallurgy of the CoCrFeMnNi high-entropy alloy : An atomistic simulation study. / Choi, Won Mi; Jo, Yong Hee; Sohn, Seok S; Lee, Sunghak; Lee, Byeong Joo.

In: npj Computational Materials, Vol. 4, No. 1, 1, 01.12.2018.

Research output: Contribution to journalArticle

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