High-entropy alloys (HEA) have emerged as promising structural materials for use in extreme environments where conventional alloys face limitations. In this study, ferritic Fe-Al-Cr-Ni-Ti alloys were developed by employing the HEA design concept to promote coherent L21 precipitation within a BCC matrix. The systematic variation of Al content enhanced lattice coherency, precipitation strengthening, and the rapid formation of protective Al2O3 scales. The alloy with 16 at% Al exhibited superior high-temperature mechanical performance, showing a yield strength of approximately 400 MPa and ~5 % uniform elongation at 700 °C, exceeding the use temperature limit of conventional steels. Steam oxidation tests demonstrated the formation of dense, continuous alumina films, while hot rolling and grain refinement effectively improved room-temperature ductility. These findings indicate that Fe-Al-Cr-Ni-Ti alloys offer a cost-effective pathway to achieve a balanced combination of heat resistance, corrosion resistance, and mechanical processability, suggesting their potential as strong candidates for next-generation energy and high-temperature structural applications.

Abstract
1. 서 론
2. 실험 방법
    2.1. 시료 준비
    2.2. 고온 인장 시험
    2.3. 수증기 산화 시험
    2.4. 열간 압연 및 상온 인장 시험
    2.5. 미세조직 분석
3. 결과 및 고찰
    3.1. 고엔트로피 기술이 적용된 페라이트계 Fe-Al-Cr-Ni-Ti 내열합금
    3.2. 석출강화형 페라이트 합금의 고온 기계적 특성
    3.3. Alumina forming 합금으로서의 고온 내부식 특성
    3.4. 페라이트계 합금의 변형수용성 향상을 위한 초미세립화
4. 결 론
References
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• 임가람(한국재료연구원 극한재료연구소) | Ka Ram Lim (Extreme Materials Research Institute, Korea Institute of Materials Science, Changwon 51508, Republic of Korea) Corresponding author