The improvement of the shape memory effect of Cu-13.5Al-4Ni high-temperature shape memory alloys through Cr-, Mo-, or V-alloying

This study presents the effect of small additions of Cr, Mo, or V on the microstructure, crystallographic features of martensitic transformation, and shape memory effect of Cu-13.5Al-4Ni master alloy. The results show that the studied alloys consist of dominant 13'1 (18R) martensitic structure and fine bcc precipitates, which are riched in the alloying elements but poor in the Cu content. The martensitic transformation starts temperatures of the alloys are 414K, 385K, and 394K when X = 0.5Cr, 0.5Mo, or 0.5V, respectively. More importantly, a drop in grain size was achieved in the studied alloys, which improved the shape memory effect in Cu-13.5Al-4Ni alloys. As a result, the studied alloys exhibit a steady increase of shape memory effect as the pre-strain changed from 6% to 10%, which the maximum shape memory effect reaching 6.2%, 5.8%, and 5.5% for X = 0.5Cr, 0.5Mo, and 0.5V, respectively.& COPY; 2023 Vietnam National University, Hanoi. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Automated summary

This study investigates the effect of adding small amounts of Cr, Mo, or V on the microstructure, crystallographic features of martensitic transformation, and shape memory effect of Cu-13.5Al-4Ni master alloy. The results show that the studied alloys consist of dominant 13'1 (18R) martensitic structure and fine bcc precipitates. The martensitic transformation starts temperatures of the alloys are 414K, 385K, and 394K for X = 0.5Cr, 0.5Mo, or 0.5V, respectively. Furthermore, a decrease in grain size improves the shape memory effect in Cu-13.5Al-4Ni alloys, with the maximum shape memory effect reaching 6.2%, 5.8%, and 5.5% for X = 0.5Cr, 0.5Mo, and 0.5V, respectively.