Martensite destabilization in Au7Cu5Al4 shape-memory alloy
Aging-induced changes in the austenite peak (AP) temperature of Au7Cu5Al4 shape-memory alloy are investigated. Whereas heat treating the parent phase at temperatures >140 degrees C or aging the martensite for long times at room temperature both stabilized the AP to approximately 80 degrees C,...
| Main Authors: | , , , |
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| Format: | Journal Article |
| Published: |
Pergamon
2011
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| Subjects: | |
| Online Access: | http://hdl.handle.net/20.500.11937/44658 |
| Summary: | Aging-induced changes in the austenite peak (AP) temperature of Au7Cu5Al4 shape-memory alloy are investigated. Whereas heat treating the parent phase at temperatures >140 degrees C or aging the martensite for long times at room temperature both stabilized the AP to approximately 80 degrees C, low-temperature excursions into the parent phase caused the subsequent AP to drop to approximately 60 degrees C and the transformation hysteresis to decrease. The evidence indicates that this destabilization of the martensite is caused by time-dependent relaxation of elastic constraint due to parent-phase lath migration during the preceding low-temperature austenitizing treatment. This mechanism of aging is different from that of the better-known symmetry-conforming short-range order phenomenon. |
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