A comprehensive review of NiTiCu alloys for actuator applications

摘要

Abstract NiTiCu shape memory alloys are promising materials for advanced actuation systems because of their enhanced mechanical properties, cyclic stability, and reduced thermal hysteresis compared to conventional binary NiTi alloys. The addition of Cu improves transformation behaviour, reduces hysteresis, and increases fatigue resistance, making these alloys suitable for applications such as robotics, aerospace, and biomedical devices. This review provides a comprehensive analysis of NiTiCu alloys, focusing on their microstructural characteristics, thermomechanical performance, and specific roles in actuation applications. The enhanced properties of NiTiCu alloys are attributed to their refined phase transformation behaviour and the stabilisation of mechanical properties under cyclic loading. However, challenges such as optimising cold work levels, managing irreversible strain, and achieving uniform microstructures persist. Strategies, including advanced thermomechanical processing, alloy composition optimisation, and emerging fabrication techniques, such as additive manufacturing, are explored to address these issues. Future research directions emphasise the integration of NiTiCu actuators into smart systems and the development of tailored compositions to expand their functionality. This review highlights the critical role of NiTiCu alloys in advancing next-generation actuation technologies and identifies pathways for enhancing their performance across a diverse range of applications.