Novel TiNiCuNb shape memory alloys with excellent thermal cycling stability

Recent Development of TiNi‐Based Shape Memory Alloys with High Cycle Stability and High Transformation Temperature

“…Among the three elements, Fe shows the largest reduction in TT, at a rate of 42 C at% À1 , [8] and Nb shows the smallest one, at a rate of 2.5 C at% À1 . [39] The alloyings of Co and Fe do not affect the cyclic stability, [8] and the proper alloying of Nb enhances the cyclic stability of phase transformation. [39]…”

“…[39] The alloyings of Co and Fe do not affect the cyclic stability, [8] and the proper alloying of Nb enhances the cyclic stability of phase transformation. [39]…”

“…[27] To date, several SMA systems satisfying the cofactor conditions have shown stable transformation and slim hysteresis, including TiNiCu, [27] TiNiCuCo, [8,14,33] ZnAuCu, [30] TiNiPd, [34] NiMnSnCo, [35] NiMnInCu, [36] TiPdCr, [37] TiNiCuFePd, [38] and TiNiCuNb. [39] Two other methods have been reported to be effective for improving the crystallographic compatibility, in addition to tailoring the chemical composition. The first one was reported by Ahadi and Sun, [40] in which λ 2 approaches 1 with decreasing grain size of the Ti 49.1 Ni 50.9 alloy to nanoscale.…”

“…Co, Fe, and Nb have been added to TiNiCu alloys to tailor the TTs. [8,39] With increasing content of alloying element, the TTs decrease. Among the three elements, Fe shows the largest reduction in TT, at a rate of 42 C at% À1 , [8] and Nb shows the smallest one, at a rate of 2.5 C at% À1 .…”

“…In this regard, a high‐throughput approach based on the thin‐film composition‐spread technique has shown its effectiveness in validating the cofactor conditions and identifying the desired alloy . To date, several SMA systems satisfying the cofactor conditions have shown stable transformation and slim hysteresis, including TiNiCu, TiNiCuCo, ZnAuCu, TiNiPd, NiMnSnCo, NiMnInCu, TiPdCr, TiNiCuFePd, and TiNiCuNb …”