United States of America As Represented by the Administrator of Nasa

Fransua Thomas

Christopher DellaCorte

Malcolm K Stanford

Ronald Dean Noebe

Glen Bigelow

A method for making small diameter NiTi metal alloy components, including balls, comprising providing a metal powder comprising nickel, titanium, and a transition metal, consolidating the metal powder into cylindrical rods, and cutting the cylindrical rods into segments. The segments are then machined into spheres slightly larger than the finished ball size diameter. The spheres are heat treated to solutionize and dissolve all phases and subsequently cooled without the need for rapid quenching due to the influence of the transition metal to suppresses the formation of soft phases in the spheres, wherein such soft phases prevent hardening, to achieve a Rockwell hardness of HRC 58-62. Finally, the hardened spheres are polished until the desired finished ball size diameter and surface finish is achieved.

Method for making small diameter nickel-titanium metal alloy balls

One or more substitutional elements may be used to reduce the solution treatment temperature and required quench rates for hardening of 60-NITINOL. The advantages of modified NITINOL include that less energy is consumed during the heat treatment process, the material is subjected to less thermal distortion, and less machining is required. Modified NITINOL may have adequate hardness for bearing applications and may display highly elastic behavior.

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Strongsville, OH, United States of America

Fransua Thomas