| Popis: |
A promising direct method of preparation by rapid solidification, the twin roll casting technique, has been used for the first time to produce semi-finite shape memory alloys thin strips (200-600 μm thick). Different NiTi and Cu-Ni-Al based compositions have been tested. Some cracks appeared on these new products but they have been partially or totally suppressed, according to the alloy composition, by optimisation of the parameters of the process and after adding side dams to the wheels. The resulting strip morphology, stricture and microstructure have been analysed, taking into account the complex heat and mass flows during the process. Transformation temperatures are in the same range of values that those of the corresponding massive materials. |
