In recent years, the applications of TiNi SMAs in microelectromechanical systems (MEMS) have got more interest because of their outstanding work output density, say 1~07 Jm~(-3) [1]. Therefore, the properties of TiNi SMAs exhibited at the microscale or even nanoscale become significant issues. Two main fabrication methods to obtain small-scale TiNi SMAs are sputtering and rapid solidification process (RSP). Recent studies on the amorphous Ti-rich TiNi thin film fabricated under low sputtering temperature discovered the nanoscale Ti-rich Guinier-Preston (GP) zones [2]. Similarly, Ti-rich GP zones have also been observed in Ti-rich TiNi ribbons prepared by rapid solidification technique [3]. To reveal the hardness evolution associated with precipitation hardening with aging time on these kinds of samples, a sophisticated equipment, nanoindenter, is employed to obtain reliable hardness values.
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