Back to Search Start Over

Abnormal grain growth of 68Cu–16Al–16Zn alloys for elastocaloric cooling via cyclical heat treatments

Authors :
Yuya Kawarada
Akihisa Aimi
Abimael Santos
Gentaro Nakata
Ichiro Takeuchi
Kenjiro Fujimoto
Source :
JPhys Energy, Vol 5, Iss 2, p 024012 (2023)
Publication Year :
2023
Publisher :
IOP Publishing, 2023.

Abstract

Cu-based superelastic shape memory alloys are promising for low-stress elastocaloric cooling. We have synthesized bulk alloys of 68Cu–16Al–16Zn under different conditions in order to promote its grain growth and enhance its elastocaloric properties. High-temperature x-ray diffraction of untreated 68Cu–16Al–16Zn alloy showed that the phase boundary between the α + β mixed phases and the high temperature phase ( β phase) was between 973 K and 1023 K. Based on this result, the 68Cu–16Al–16Zn alloy was heated and cooled in a furnace repeatedly between 773 K and 1173 K. The maximum grain size after heat treatment of the ingot rolled to 67% reached 11.1 mm. The latent heat of the martensitic transformation after grain growth was 6.3 J g ^−1 , which is higher than the previously reported value for the compound. The stress–strain curve of 68Cu–16Al–16Zn rolled to 67% rolling with cyclical heat treatments showed a maximum stress of 106 MPa at 4.5% strain, with adiabatic temperature change of 5.9 K in heating during stress loading and 5.6 K in cooling in stress removal. Furthermore, no fatigue in the stress–strain behavior was observed up to at least 60 000 mechanical cycles at 2% strain.

Details

Language :
English
ISSN :
25157655
Volume :
5
Issue :
2
Database :
Directory of Open Access Journals
Journal :
JPhys Energy
Publication Type :
Academic Journal
Accession number :
edsdoj.17f4c754635e4a2bae94eb33279e9244
Document Type :
article
Full Text :
https://doi.org/10.1088/2515-7655/acc5b2