20.500.12556/DKUM-27025 Microstructure of rapidly solidified Cu-Al-Ni shape memory alloy ribbons 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. metallurgy shape memory alloys Cu-Al-Ni alloy microstructure melt spinning metalurgija zlitine z oblikovnim spominom zlitina Cu-Al-Ni mikrostruktura true false false Angleški jezik Angleški jezik Neznano 2012-06-01 09:39:13 2012-06-01 09:39:13 2022-04-15 03:43:13 2019-07-10 12:10:40 2005 0 0 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 669.018 9607190 0924-0136 URN:SI:UM:DK:SXUPLTDV http://dx.doi.org/10.1016/j.jmatprotec.2005.02.196 1 https://dk.um.si/Dokument.php?lang=slv&id=36260 Fakulteta za strojništvo 0 0 0