Grain-size dependence of shape memory effect and damping capacity in melt-spun Zr-Cu-based shape memory alloy ribbons

Zr-Cu-based shape memory alloy ribbons are promising candidates for micro-actuators and damping devices in Micro-Electro-Mechanical Systems applications. However, the grain size effect on the shape memory effect and damping capacity remains unclear. In this study, we utilized the melt-spinning technique combined with annealing treatment to obtain ribbons with varying grain sizes. The effects on both shape memory effect and damping capacity were systematically investigated. The results show that grain coarsening increases both the martensitic transformation temperatures and latent heat. Specifically, M_s increased from −34.7 °C at 168 nm to 80.5 °C at 383 nm, while ΔH_AM decreases from −2.08 to −6.23 J/g. The maximum shape recovery strain and work output at 100 MPa increased with increasing grain size, from 0.34% and 0.34 J/cm³ at 201 nm to 0.65% and 0.65 J/cm³ at 383 nm. Conversely, the damping capability in the martensitic state diminished with grain coarsening, as the tanδ fell from 0.053 at 201 nm to 0.031 at 383 nm. This work provides insight into the applications of Zr-Cu ribbons in micro-actuation and vibration control.