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Phase-Resolved Defect Transport Mechanisms Governing Asynchronous Ordering in a Eutectic High-Entropy Alloy
Huiwen Yao1,2, Qingshuang Ma1,2, Jie Xiong3
1School of Materials Science and Engineering, Northeastern University, Shenyang, P. R. China.
Summary
Eutectic high-entropy alloys (EHEAs) show different phase changes due to unique defect behaviors. Understanding these mechanisms is key to designing stable complex alloys.
Area of Science:
- Materials Science
- Metallurgy
- Solid-State Physics
Background:
- Eutectic high-entropy alloys (EHEAs) display complex, asynchronous phase evolution during thermal treatment.
- The fundamental mechanisms driving these differing phase transformations remain largely unexplored.
Purpose of the Study:
- To elucidate the mechanisms behind the asynchronous phase evolution in EHEAs.
- To investigate the isothermal annealing behavior of the AlCoCrCuFeNi alloy.
Main Methods:
- Phase-resolved experimental techniques, including electron microscopy.
- Atomistic simulations, such as molecular dynamics and Monte Carlo simulations.
Main Results:
- Electron microscopy showed distinct structural pathways: BCC-FeCr developed long-range order, while B2-NiAl underwent local relaxation.
- Simulations revealed phase-dependent defect energetics influencing transport mechanisms.
- B2-NiAl exhibited efficient vacancy-mediated transport, whereas BCC-FeCr utilized a cooperative vacancy-interstitial mechanism.
Conclusions:
- Heterogeneous defect transport mechanisms are responsible for asynchronous ordering in EHEAs.
- This phase-resolved understanding provides a basis for designing thermally stable complex alloys.
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