Melt-cast microfibers of Cu-based shape memory alloy adopt a favorable texture for superelasticity

Abstract

Continuous production of shape memory alloy (SMA) fibers and microfibers is a non-trivial task due to the challenges associated with their undeformed memory and, for many copper-based SMAs, brittleness in non-engineered forms. Here we demonstrate the direct continuous casting of super-meter-scale Cu-based SMA microfibers into a desirable oligocrystalline microstructure that is not brittle. The melt-casting process used here develops a favorable texture as well, leading to large superelastic strains (above 8%), beyond what is typical for non-single-crystal SMAs. Keywords: Shape memory alloys; Fibers; Martensitic phase transformations