A Practical Guide to Ternary Nitinol Alloys

The authors will survey the state-of-the art with respect to using ternary and quarternary additions to tailor the microstructure and the properties of Nitinol. The quantitative boundaries of the element additions will be reviewed with regards to melting as well as hot and cold workability.   

 Discussed will be the use tantalum and hafnium to stabilize martensite (increase hysteresis) and the use of iron, chrome, aluminum and cobalt to suppress martensite, as well as the role of copper and niobium respectively to contract or expand hysteresis.  The effects of platinum and palladium additions will also be discussed. Minor element additions and their effect on the microstructure and microcleanliness of Nitinol will also be mentioned during this review.

The authors will provide commentary on gains one can make with ternary additions, the sacrifices, and what has been done from a commercial perspective.