Reversible changes in yield stress and transformation temperature of a NiTi alloy by alternate heat treatments

Effect of indentation temperature on nickel-titanium indentation-induced two-way shape-memory surfaces

“…Generally, the R-phase is seen in compositions with slightly higher nickel content, typically above Ti-50.5at%Ni (Khalil Allafi et al 2002;Khalil-Allafi et al 2002), and can be induced with proper heat treatment and the formation of precipitate structures (Cong et al 2014;Wang, Verlinden, et al 2015;Wang, Kustov, et al 2015). Studies on NiTi compositions of lower nickel content suggest that the R-phase transformation can be induced through a combination of heat treatment and material processing, such as cold working (Mahmud et al 2008;Okamoto et al 1988;Todoroki 1985;Todoroki & Tamura 1986;Goo & Sinclair 1985). It has also been proposed that grain sizes below 150 nm in Ni-rich NiTi can impede the formation of precipitate structures in NiTi (Prokofiev et al 2010).…”

Cyclic ageing of Ti–50.8at.% Ni alloy

“…In 1988, Horikawa et al [12] conducted a study of ''short-time'' cyclic anneals between 713 K and 783 K of a Tie51 at.% Ni alloy. They observed an interesting up-and-down movement of the transformation temperatures with anneal cycles.…”

A study of Ti50−x/2Ni40−x/2Cu10Crx (x = 0 ∼ 1at.%) shape memory alloys

“…The transformation behaviors and mechanical properties in TiNi binary alloys can be affected by various thermo-mechanical treatments, such as thermal cycling [4,5], aging in Ni-rich alloys [6][7][8][9], and annealing after cold working [10][11][12][13]. Furthermore, the addition of a third element has a substantial effect on transformation behaviors in TiNi alloys.…”