| Title: | Microstructure of rapidly solidified Cu-Al-Ni shape memory alloy ribbons |
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| Authors: | ID Lojen, Gorazd (Author)
ID Anžel, Ivan (Author)
ID Kneissl, Albert C. (Author)
ID Unterweger, Elfride (Author)
ID Kosec, Borut (Author)
ID Bizjak, Milan (Author) |
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| Files: |  http://dx.doi.org/10.1016/j.jmatprotec.2005.02.196
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| Language: | English |
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| Work type: | Unknown |
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| Typology: | 1.01 - Original Scientific Article |
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| Organization: | FS - Faculty of Mechanical Engineering
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| Abstract: | Cu-Al-Ni shape memory alloys (SMAs) are currently the only available high temperature SMAs, showing a good resistance against functional fatigue. In polycrystalline state, they are very brittle and exhibit, in general, only small reversible deformations. By melt spinning, thin Cu-Al-Ni ribbons can be manufactured directly from the melt. Appropriate casting parameters can ensurea single layer columnar structure with a fibre texture, which significantly increases the maximal reversible strain in longitudinal direction. Cu-Al-Ni ribbons, containing 13, 14 and 15 wt.% Al were cast by free jet melt spinning. Because of the alloys' low thermal conductivity, the cooling rate was surprisingly low - considering the crystal grain size - significantly below 103 K/s. Therefore, wide ribbons having a single layer columnar and (except the ribbons containing 13 wt.% Al) completely martensiticstructure could not be obtained. Regardless the chemical composition, the ribbons have a single layer columnar structure only if the thickness does not exceed approximately 50 m, otherwise the structure consists of at least two layers of equiaxed grains. In as-cast condition, only ribbons containing 13 wt.% Al seem to be completely martensitic. Heat treatments at temperatures up to 900 °C improved the structure of 13 and 14 wt.% Al ribbons. All ribbons exhibit one-way shape memory effect in as-cast condition. Heat-treated ribbons containing 13 wt.% Al exhibited two-way shape memory effect already after one bending and heating cycle. |
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| Keywords: | metallurgy, shape memory alloys, Cu-Al-Ni alloy, microstructure, melt spinning |
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| Year of publishing: | 2005 |
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| PID: | 20.500.12556/DKUM-27025  |
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| UDC: | 669.018 |
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| ISSN on article: | 0924-0136 |
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| COBISS.SI-ID: | 9607190 |
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| NUK URN: | URN:SI:UM:DK:SXUPLTDV |
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| Publication date in DKUM: | 01.06.2012 |
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| Views: | 2800 |
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| Downloads: | 122 |
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| Metadata: |    |
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| Categories: | Misc.
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