Microstructure, martensitic transformation and shape memory effect of novel Cu-Al-Ga based shape memory single crystals

In this study, the shape memory effect of novel iron-alloyed Cu-Al-Ga shape memory single crystals were re-ported for the first time. The microstructure, crystal structure, martensitic transformation and shape memory effect of Cu-10Al-6Ga (master alloy), Cu-10Al-6Ga-3Fe, Cu-12Al-4Ga-3Fe and Cu-14Al-4Ga-3Fe (wt.%) were investigated. All studied alloys consist of dominant martensite and fine bcc nanoparticles with richer Fe content and poorer Cu content except master alloy. The martensitic transformation start temperatures are 241.3 degrees C, 251.3 degrees C and 71.9 degrees C for Cu-10Al-6Ga-3Fe, Cu-12Al-4Ga-3Fe and for Cu-14Al-4Ga-3Fe alloys, respectively. For master alloy, the martensitic transformation disappears resulted from the precipitation of a large amount of alpha-Cu during heating. In addition, the shape memory effects clearly increase as a result of increase of the pre-strains. The Cu-14Al-4Ga-3Fe single crystal obtains a maximum shape memory effect of 6.8% with 100% strain recovery when 10% pre-strain is applied.

Automated summary

This study reports for the first time the shape memory effect of novel iron-alloyed Cu-Al-Ga shape memory single crystals. The microstructure, crystal structure, martensitic transformation and shape memory effect of different compositions were investigated. The alloys consist of dominant martensite and fine bcc nanoparticles, except for the master alloy. The martensitic transformation start temperatures vary among the studied alloys. The shape memory effect clearly increases with increase of pre-strains, reaching a maximum of 6.8% strain recovery for Cu-14Al-4Ga-3Fe single crystal with 10% pre-strain.