Temperature dependence of pseudoelasticity and shape memory effect in Fe3Ga single crystals with D03 structure

Abstract

Pseudoelastic behavior and shape memory effect in D03-ordered Fe-24.4at%Ga single crystals deformed at different temperatures were investigated focusing on the microstructure and dislocation configuration. High strain recovery ratios more than 80% could be obtained at temperatures between -100 and 100°C. In particular, perfect pseudoelasticity appeared in the crystals deformed at room temperature. During unloading, antiphase boundaries (APB) left behind 1/4〈111〉 superpartial dislocations pulled back the superpartials resulting in the pseudoelasticity. In addition, Fe3Ga single crystals compressed at -150°C demonstrated shape memory effect during heating to room temperature. On the other hand, the recovery ratio decreased with increasing deformation temperature up to 300°C and remained constant at about 10%. The L12 phase precipitating during deformation, dislocation configuration associated with 1/4〈111〉 superpartials connected by two kinds of APB and relaxation of the APB were found to strongly influence the pseudoelasticity and shape memory effect in Fe3Ga single crystals. © 2008 ISIJ.