Stabilization of martensite in Cu-Zn-Al shape memory alloys: Effects of {gamma} precipitates and thermal cycling
The applications of copper based shape memory alloys requiring a prolonged use in the martensitic state have been restricted due to their aging behavior which results in the increase of the reverse martensitic transformation temperatures with time, effect known as stabilization of martensite. The shift of reverse transformation temperatures is only present in the first retransformation after quench and/or aging. When the material reverts to the high temperature (beta) phase a rapid recovering process takes place in such a way that for the following transformations cycles, the normal transformation temperatures are re-established. The effects of thermal cycling (repetition of the temperature induced martensitic transformation) on the transformation characteristics of Cu-based shape memory alloys have been studied by several authors. On the other hand, it is known that the presence of {gamma} precipitates inside the parent {beta}-Cu-Zn-Al phase can produce strong modifications on the transformation temperatures and its thermal hysteresis. In this work the authors present results on the martensite stabilization, produced by aging at room temperature, in Cu-Zn-Al alloys with different distributions of {gamma} phase precipitates with and without thermal cycling, which are compared to the stabilization behavior found in precipitate-free samples.
- Research Organization:
- Univ. Autonoma de San Luis Potosi (MX)
- OSTI ID:
- 20023176
- Journal Information:
- Scripta Materialia, Journal Name: Scripta Materialia Journal Issue: 6 Vol. 42; ISSN 1359-6462; ISSN SCMAF7
- Country of Publication:
- United States
- Language:
- English
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