“Until now no one has been able to explore these superelasticity properties in micrometric and nanometric sizes,” explained Professor José María San Juan.
By using a focused ion beam, the team built micropillars and nanopillars of copper-aluminium-nickel alloy with diameters ranging between 2µm and 260nm. They applied a stress to these pillars using a nanoindenter.
Through this experiment, the researchers confirmed and quantified that in diameters of less than a micrometre there is a considerable change in the properties relating to the critical stress for superelasticity.
“The alloy continues to display superelasticity but for much higher stresses,” said Prof San Juan.
This superelastic behaviour is opening up new channels in the application of microsystems involving flexible electronics and microsystems that can be implanted into the human body.
“It will be possible to build tiny micropumps or microactuators that can be implanted on a chip, and which will allow a substance to be released and regulated inside the human body for a range of medical treatments,” Prof San Juan concluded.