Superelastic and Shape Memory Single Crystal CuAlNi: Fabrication and Applications
Dr. Valery Martynov1, Michael D. Bokaie1, Dr. A.David Johnson2 and Mr. George Robert Gray2, 1TiNi Aerospace, 2235 Polvorosa Avenue, San Leandro, CA 94577, 2TiNi Alloy Company, 13003 Neptune Drive, San Leandro, CA 94577

A crystal grower for pulling from a melt of Cu-Al-Ni alloys different single crystalline profiles was designed and built in TiNi Aerospace Company. The grower utilizes Stepanov’s method and enables pulling various profiles (including hollow ones) of oriented single crystals up to 20 inches long. By varying the alloy formulation transformation temperatures of the crystals can be adjusted in the temperature range from –196 to + 200 oC.
 
Elimination of grain boundaries from the material dramatically improves its mechanical properties and allows single crystals to reach the theoretical limit of strain recovery both in superelastic and shape memory applications of the single crystals.  Cylindrical rods and flat profiles of various sizes and transformation intervals have been pulled and tested. Some prospective applications of single crystalline Cu-Al-Ni SMA (SSMA) will be presented and discussed.

Session 6: Alloy Production and Processing

The Preliminary Program for The International Conference on Shape Memory and Superelastic Technologies (May 7-11, 2006)