Nickel-titanium (NiTi) alloy, composed of nearly equal atomic ratios of nickel and titanium, is renowned as a "memory metal" due to its unique shape memory effect and superelasticity. NiTi alloy wire has become a star product in materials science, playing an irreplaceable role in fields such as healthcare, aerospace, and smart devices.

‌· Shape Memory Effect:‌ NiTi alloy wire can recover its original shape when heated to a critical temperature after low-temperature deformation. This property stems from the reversible phase transformation between austenite and martensite in its crystal structure, making it ideal for self-adjusting devices.
‌· Superelasticity:‌ Within the human body temperature range, NiTi alloy wire can withstand up to 8% strain and fully recover, far exceeding the elastic limits of traditional metals. This makes it exceptional for scenarios requiring repeated deformation.
‌· Biocompatibility:‌ A stable titanium oxide layer forms on the surface of NiTi alloy, significantly reducing nickel ion release risks. It has passed multiple biosafety certifications and is widely used in implantable medical devices.

‌Medical Industry:‌ NiTi alloy wire is a core material for cardiovascular stents, orthodontic archwires, and minimally invasive surgical tools. For example, cardiovascular stents expand at body temperature to provide long-term vascular support, reducing restenosis risks.
‌Aerospace:‌ NASA employs NiTi alloy wire in satellite antenna deployment mechanisms, where its lightweight and high reliability meet the demands of harsh space environments.
‌Smart Devices:‌ In robotics, NiTi alloy wire serves as a micro-actuator, enabling precise movements via temperature or electrical control, advancing flexible robotics technology.

Despite its advantages, challenges such as high costs, complex processing, and long-term fatigue performance remain. Current research focuses on developing low-cost manufacturing techniques (e.g., 3D printing), improving fatigue resistance, and exploring applications in wearables and energy. As demand for smart materials grows, NiTi alloy wire is poised to break new ground, becoming a cornerstone of future technological innovation.