Superelasticity is a characteristic thermomechanical property in shape memory alloys (SMA), which is due to a reversible stress-induced martensitic transformation. Nano-compression experiments made possible the study of this property in Cu–Al–Ni SMA micropillars, showing an outstanding ultra-high mechanical damping capacity reproducible for thousands of cycles and reliable over the years. This scenario motivated the present work, where a comparative study of the damping capacity on four copper-based SMA: Cu–Al–Ni, Cu–Al–Be, Cu–Al–Ni–Be and Cu–Al–Ni–Ga is approached. For this purpose, [001] oriented single-crystal micropillars of comparable dimensions (around 1 µm in diameter) were milled by focused ion beam technique. All micropillars were cycled up to two hundred superelastic cycles, exhibiting a remarkable reproducibility. The damping capacity was evaluated through the dimensionless loss factor η, calculated for each superelastic cycle, representing the dissipated energy per cycle and unit of volume. The calculated loss factor was averaged between three micro-pillars of each alloy, obtaining the following results: Cu–Al–Ni η = 0.20 ± 0.01; Cu–Al–Be η = 0.100 ± 0.006; Cu–Al–Ni–Be η = 0.072 ± 0.004 and Cu–Al–Ni–Ga η = 0.042 ± 0.002. These four alloys exhibit an intrinsic superelastic damping capacity and offer a wide loss factor band, which constitutes a reference for engineering, since this kind of micro/nano structures can potentially be integrated not only as sensors and actuators but also as dampers in the design of MEMS to improve their reliability. In addition, the study of the dependence of the superelastic loss factor on the diameter of the pillar was approached in the Cu–Al–Ni–Ga alloy, and here we demonstrate that there is a size effect on damping at the nanoscale.

超弹性是形状记忆合金 (SMA) 的一种特征热机械性能，这是由于可逆应力引起的马氏体转变造成的。纳米压缩实验使研究 Cu-Al-Ni SMA 微柱的这种特性成为可能，显示出出色的超高机械阻尼能力，可重复数千次循环，并且多年来可靠。这种情况激发了目前的工作，其中对四种铜基 SMA 的阻尼能力进行了比较研究：Cu-Al-Ni、Cu-Al-Be、Cu-Al-Ni-Be 和 Cu-Al-Ni-Ga接近。为此，通过聚焦离子束技术研磨了具有可比尺寸（直径约 1 µm）的 [001] 取向单晶微柱。所有微柱都进行了多达 200 次超弹性循环，表现出显着的可重复性。η，为每个超弹性循环计算，代表每个循环和单位体积的耗散能量。计算的损耗因子在每种合金的三个微柱之间取平均值，得到以下结果：Cu-Al-Ni η  = 0.20 ± 0.01；Cu-Al-Be η  = 0.100 ± 0.006；Cu-Al-Ni-Be η  = 0.072 ± 0.004 和 Cu-Al-Ni-Ga η = 0.042 ± 0.002。这四种合金表现出固有的超弹性阻尼能力并提供宽的损耗因子带，这构成了工程参考，因为这种微/纳米结构不仅可以集成为传感器和执行器，还可以作为阻尼器设计MEMS 以提高其可靠性。此外，在 Cu-Al-Ni-Ga 合金中研究了超弹性损耗因子对支柱直径的依赖性，在这里我们证明了纳米级阻尼的尺寸效应。