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Stabilization and Destabilization in Melt-spun Cu-Al-Ni Based SMA Ribbons
|G.S. Yang 3, Kwang K. Jee 1, W. Y. Jang 2|
1. Korea Institute of Science and Technology, Material Science and Engineering Division, Seoul, Korea, South
In order to clarify the destabilization condition, the effect of heat treatments i.e. flash heating and aging on the microstructure and transformation characteristics of stabilized ribbons on account of chemical composition and wheel speed has been studied in Cu-Al-Ni based SMA melt-spun ribbons.
By flash heating above 750 ℃ × 5 sec, the parent phase was not retained at room temperature because of the disappearance of lattice defects introduced during melt spinning, while the grain size of the flash-heated ribbon became coarser with increasing flash-heating temperature.
When as-spun ribbon was aged at 600 ℃, remarkable change in microstructure was not observed with increasing aging time but transformation temperatures of the ribbon aged at 600 ℃ were lower than those in as-spun ribbon. With increasing aging temperature to 100 ℃ and 200 ℃, the volume fraction of retained parent phase was decreased, resulting in destabilization of parent phase. Microstructure of the ribbons aged at 100 ℃ and 200 ℃ were changed to columnar structure and Ms and As temperatures were risen with increasing aging temperature and time.
Presentation: poster at E-MRS Fall Meeting 2005, Symposium C, by W. Y. Jang
See On-line Journal of E-MRS Fall Meeting 2005
Submitted: 2005-05-20 14:39 Revised: 2009-06-07 00:44