Considerations In The Selection Of Superelastic Nitinol For Medical Device Design

The design of medical devices offers a unique set of challenges, related to necessary fatigue life, required strength attributes, achievable delivery system profile, ease of manufacturing and, ultimately, cost. The use of superelastic materials such as nitinol, can effectively address this broad spectrum of design considerations. Superelastic nitinol can be manufactured in various ways, and in various alloy forms, allowing a high degree of flexibility in achievable material properties, which allows for material tailoring relative to specific device applications.

In this investigation, the general characteristic differences of binary, ternary, quaternary and an unconventionally processed binary nitinol are discussed in relation to the details of medical device design needs. Specific experimental data comparative to superelastic properties for these materials, as well as fatigue endurance limit data (from fatigue to fracture evaluations) will be discussed, and the properties will be considered and compared relative to the needs of medical device design, using specific examples to illustrate the differences and their importance to medical device design considerations.