High-entropy alloys (HEAs) are generally defined as solid solutions containing at least 5 constituent elements with concentrations between 5 and 35 atomic percent without the formation of intermetallic compounds. Currently, HEAs receive great attention as promising candidate materials for extreme environments due to their potentially desirable properties that result from their unique structural properties. In this review paper, we aim to introduce HEAs and explain their properties and related research by classifying them into three main categories, namely, mechanical properties, thermal properties, and electrochemical properties. Due to the high demand for structural materials in extreme environments, the mechanical properties of HEAs including strength, hardness, ductility, fatigue, and wear resistance are mainly described. Thermal and electrochemical properties, essential for the application of these alloys as structural materials, are also described.

Abstract
1. 서 론
2. 고엔트로피 합금의 열역학적 정의 및 조건
3. 고엔트로피 합금의 특성
    3.1. 기계적 특성
    3.2 열적 특성
    3.3 전기화학적 특성
4. 맺음말
References

• 박푸른솔(서울과학기술대학교 신소재공학과) | Pureunsol Park (Department of Materials Science and Engineering, Seoul National University of Science and Technology)
• 이호준(서울과학기술대학교 신소재공학과) | Ho Joon Lee (Department of Materials Science and Engineering, Seoul National University of Science and Technology)
• 조영준(서울과학기술대학교 신소재공학과) | Youngjun Jo (Department of Materials Science and Engineering, Seoul National University of Science and Technology)
• 구본승(서울과학기술대학교 신소재공학과) | Bonseung Gu (Department of Materials Science and Engineering, Seoul National University of Science and Technology)
• 최원준(한양대학교 신소재공학과) | Won June Choi (Department of Materials Science and Engineering, Hanyang University)
• 변종민(서울과학기술대학교 신소재공학과/서울과학기술대학교 분말기술연구소) | Jongmin Byun (Department of Materials Science and Engineering, Seoul National University of Science and Technology/The Institute of Powder Technology, Seoul National University of Science and Technology) Corresponding Author