# CrFeVWX (X = Ta or Ti) High-Entropy Alloy: A Theoretical and Experimental Comparative Investigation on Phase Stability

## TL;DR

This study explores CrFeVWX high-entropy alloys for use in extreme environments like nuclear fusion reactors, comparing their stability and properties through simulations and experiments.

## Contribution

The paper presents a comparative theoretical and experimental investigation of CrFeTaVW and CrFeTiVW high-entropy alloys for phase stability and performance.

## Key findings

- Monte Carlo simulations predict lower potential energy and more stable structures for both alloys compared to Molecular Dynamics.
- CrFeTaVW shows lower chemical segregation in Monte Carlo simulations, while CrFeTiVW shows the opposite trend.
- Experimental results confirm bcc structures in both alloys, with CrFeTaVW also showing an Fe2Ta Laves phase.

## Abstract

Materials capable of withstanding extreme environments open promising opportunities for nuclear fusion reactors. In this study, equiatomic CrFeTaVW and CrFeTiVW high-entropy alloys are investigated as interlayer materials between W and CuCrZr. Monte Carlo and Molecular Dynamics simulations predicted a bcc-type structure for both systems. Additionally, the Monte Carlo simulation predicts lower potential energy and a more stable structure for both systems than Molecular Dynamics. For CrFeTaVW, the chemical segregation values are lower in MC than in the MD simulation, whereas for CrFeTiVW, the opposite trend is observed, with MC indicating stronger segregation values. After simulation, the high-entropy alloys were prepared by planetary ball milling, consolidated by spark plasma sintering, and analyzed using X-ray diffraction, scanning electron microscopy, and thermal diffusivity. The experimental results for the milled powders confirmed the formation of a bcc structure in both alloys. The consolidated material revealed a bcc-type structure and an Fe2Ta Laves phase for the CrFeTaVW HEA, while the CrFeTiVW HEA exhibits two different bcc-type structures. The values of CrFeTaVW and CrFeTiVW thermal diffusivity are between 3.5 and 7 mm2/s, which is consistent with the expected values for high-entropy alloys. Overall, the findings indicate that these HEAs have promising properties that can be used in extreme environments.