Effect of ta additions on the microstructure, damping, and shape memory behaviour of prealloyed Cu-Al-Ni shape memory alloys

• Main Authors: Saud, S. N., Hamzah, E., Bakhsheshi Rad, H. R., Abubakar, T.
• Format: Article
• Language: English
• Published: Hindawi Limited 2017
• Subjects: TJ Mechanical engineering and machinery
• Online Access: http://eprints.utm.my/id/eprint/74922/1/EHamzah_EffectofTaAdditionsontheMicrostructure.pdf; http://eprints.utm.my/id/eprint/74922/; https://www.scopus.com/inward/record.uri?eid=2-s2.0-85029395630&doi=10.1155%2f2017%2f1789454&partnerID=40&md5=4f7b28d54a07926e1863aa85f3af4e79
• Institution: Universiti Teknologi Malaysia

The influence of Ta additions on the microstructure and properties of Cu-Al-Ni shapememory alloys was investigated in this paper. The addition of Ta significantly affects the green and porosity densities; the minimum percentage of porosity was observed with the modified prealloyed Cu-Al-Ni-2.0wt.% Ta. The phase transformation temperatures were shifted towards the highest values after Ta was added. Based on the damping capacity results, the alloy of Cu-Al-Ni-3.0 wt.% Ta has very high internal friction with the maximum equivalent internal friction value twice as high as that of the prealloyed Cu-Al-Ni SMA. Moreover, the prealloyed Cu-Al-Ni SMAs with the addition of 2.0wt.% Ta exhibited the highest shape recovery ratio in the first cycle (i.e., 100% recovery), and when the number of cycles is increased, this ratio tends to decrease. On the other hand, the modified alloys with 1.0 and 3.0 wt.% Ta implied a linear increment in the shape recovery ratio with increasing number of cycles. Polarization tests in NaCl solution showed that the corrosion resistance of Cu-Al-Ni-Ta SMA improved with escalating Ta concentration as shown by lower corrosion current densities, higher corrosion potential, and formation of stable passive film.