Abstract
Nowadays, there is a great interest in developing new families of shape memory alloys (SMA) exhibiting thermomechanical properties beyond the classical ones obtained with the well-known NiTi SMA and the derived ternary alloys. Indeed, a great effort is being focused in developing high-temperature SMA, like the ones based on NiTiHf/Zr or on Cu-Al-Ni, and also on the development of SMA that could be successfully implemented at micro and nanoscale for smart micro electro-mechanical systems (MEMS) applications. However, new hydrogen-based energy sources, high-power nuclear fusion and the emerging quantum computing technologies, as well as the classical superconducting ones, require low-temperature working environments. All of them need the use of sensors and actuators at cryogenic temperatures, but, at present, there are not shape memory alloys (SMA) offering the possibility of operating as sensors and actuators, valves for instance, at so low temperatures, below liquid nitrogen.
