Nitinol alloys have long been a core material in medical and industrial applications due to their unique super-elastic properties. Fort Wayne Metals developed a new generation of Nitinol-based super-elastic (SE) alloys that push the previous boundaries of strength and performance. With upper plateau strengths exceeding 1.0 GPa and lower plateau strengths above 600 MPa, these advanced materials unlock new possibilities across a range of demanding applications.

Enhanced strength for medical applications

The ability to achieve high plateau stresses allows medical device engineers to develop components with thinner profiles while maintaining or even increasing mechanical performance. For instance, vascular guidewires and orthodontic arch wires made from these advanced Nitinol alloys can deliver greater force in smaller wire diameters.

Tensile stress-strain testing of one such alloy, NiTiNbY, revealed remarkable improvements over traditional binary Nitinol alloys. NiTiNbY demonstrated a forward loading plateau stress of 1100 MPa—an increase of more than 65% compared to conventional Nitinol’s 650 MPa. Additionally, its unloading plateau stress is double that of standard Nitinol, while its axial elastic modulus is 40-50% higher. These improvements mean that medical devices, such as stents and guidewires, can be designed with thinner structures without compromising outward force or performance.

While higher stresses can enhance push-ability and torque in guidewires, engineers must consider durability, particularly for permanent implants. However, for temporary devices, the benefits are substantial. Orthodontic arch wires, for example, can provide double the bending force compared to traditional Nitinol wires, enhancing treatment efficiency.

Superelasticity at cryogenic temperatures for space applications

One of the most remarkable attributes of these alloys is their ability to retain super-elastic properties even at extremely low temperatures. Traditional Nitinol alloys transform to martensite upon cooling, losing their super-elastic behavior. However, NiTiNbY and similar compositions maintain stable super-elastic recovery even at -130°C, as shown in stress-strain testing. This property makes them ideal for applications in space exploration and other extreme environments.

Potential space applications include deployable structures, springs, and even advanced tire designs for extraterrestrial exploration. A spring or textile-based tire made from NiTiNbY alloy could be compacted for transport and then deployed to operate over a broad temperature range while maintaining high load-carrying capabilities.

If you are interested in the future of Nitinol alloy spring tires and our collaboration with NASA, please explore our most recent research.

Categories: Materials Science, Medical device materials, Nitinol innovations, Research & development, Robotics & aerospace applications, Superelastic alloys