Improved functional stability of Ti-rich TiNi shape memory ribbon prepared by melt-spinning

Nanostructured Ti–Ni–Co Alloys Showing Shape‐Memory Actuation of Large Work Output at Low Temperature

“…As the applied biased stress increases, the alloy undergoes B2-B19 0 transformation directly and thereby the actuation response of R transformation disappears. [18,24] In addition, a high-biased stress gives rise to a large output strain, as more martensite variants are aligned along the favorable orientation, whereas excessive stress would cause plastic deformation during the phase transformation, leaving the irreversible strain after heating. Although the martensitic transformation temperature (M s ) under stress-free condition of the Co1 alloy is lower than À50 °C (Figure 1b), the large biased stress significantly increases the M s to even above the room temperature.…”

“…As the applied biased stress increases, the alloy undergoes B2–B19′ transformation directly and thereby the actuation response of R transformation disappears. [ 18,24 ]…”

“… Comparison of work output as a function of actuation response temperature upon cooling (i.e., ) for the alloys with different Co contents and other reported shape‐memory alloys, including Ti–Ni binary, [ 13,17,18,43–45 ] Ti–Ni–Cu based, [ 46,47 ] Ti–Ni–Pd based, [ 48,49 ] Ti–Ni–Hf based, [ 50–53 ] Ti–Ni–Fe, [ 54,55 ] and Cu–Al–Mn [ 11 ] alloys.…”

“…[29,31] The distinct deformation behaviors among Co1, Co4, and Co6 are likely due to their different microstructures, which are shown in Section 2.5. [13,17,18,[43][44][45] Ti-Ni-Cu based, [46,47] Ti-Ni-Pd based, [48,49] Ti-Ni-Hf based, [50][51][52][53] Ti-Ni-Fe, [54,55] and Cu-Al-Mn [11] alloys.…”

“…[15,16] In addition, according to the Clausius-Clapeyron equation, the transformation temperature also significantly increases with the increase of external biased stress. [17,18] Therefore, it is still challenging to achieve both the low actuation temperature and the high recoverable actuation strain simultaneously.…”