Advances and Critical Perspectives on High-Entropy Shape Memory Alloys: Trends, Challenges, and Future Directions

Abstrak

This review critically examines developments in high-entropy shape memory alloys (HESMAs), with particular emphasis on Fe-based and NiTi-based systems. By evaluating these alloy families within a common comparative framework, it considers how high-entropy alloy design and additive manufacturing may connect established metallurgical approaches with the development of advanced functional materials. Reported trends in transformation temperatures, fatigue performance, corrosion resistance, and super elasticity are synthesized through comparative figures and tables. The analysis highlights the complementary advantages of Fe-based alloys, including relatively low cost and strong damping capacity, and NiTi-based alloys, which are valued for super elasticity and established biomedical use. It also considers emerging multi-component systems that exhibit different phase-transformation characteristics. Key unresolved issues include the scarcity of long-term fatigue data, limited biological validation of multi-component NiTi alloys, and barriers to scaling additive manufacturing. Priorities for future work include systematic biocompatibility assessment, hybrid processing strategies, and computational modeling of transformation kinetics. The review aims to support evidence-based alloy design for structural, biomedical, and aerospace applications.