Simultaneously improving memory effect and mechanical properties in Cu-based alloys by α phase spheroidization and Fe alloying: A CuAlMnFe as an example

Abstract

The spheroidization of lamellar Fe3C in pearlite in steels can significantly increase the plasticity. Inspired by the fact, we proposed that to introduce ductile spherical α phase with precipitates of κ phase by Fe alloying can realize not only better shape memory effect (SME) but also higher mechanical properties than to introduce the blocky α phase does in Cu-based alloys. To confirm our idea, the effects of two annealings in two-phase region were studied on the spheroidization of α phase and precipitation of κ phase and the resultant SME and mechanical properties in a Cu8.5Al9.6Mn3.2Fe alloy. Our results showed that the two annealings could simultaneously spheroidize the α phase and precipitate the κ phase in the alloy. The alloy with the spherical α phase showed ∼1% higher recovery strain and ∼8% higher fracture strain than the alloy with the blocky α phase did. The spheroidization of α phase together with the precipitation of κ phase will be a direction for developing ductile Cu-based alloys with better SME and higher strength.