Relationship between grain size and martensitic transformation start temperature in a Ti–30Ni–20Cu alloy ribbon

Crystallization behavior of cold worked Ti–30Ni–20Cu(at%) alloy ribbons

“…Therefore, it is believed that cold working assists crystallization of amorphous Tie30Nie20Cu alloy. The heat of transformation for crystallization of CR ribbons is known to be 37.5 J/g at the heating rate of 10 K/min, which is very close to that of AS ribbons(36.2 J/g) [10]. Fig.…”

“…4(a) and (b). From the previous study [10], AS Tie30Nie20Cu ribbons annealed at various temperatures showed homogenous grain size distribution. Therefore, the inhomogeneous grain size distribution is ascribed to deformation effect.…”

“…The present authors showed that a Tie30Nie20Cu alloy with an average grain size of 0.7 mm was obtained by thermally-induced crystallization, i.e. crystallization by annealing amorphous Tie30Nie20Cu alloy, which is very small comparing that of the alloy prepared by conventional casting [10]. Deformation induced crystallization has been also known to result in nanocrystalline materials by the deformation-driven nanocrystal catalytic reaction [11,12].…”

Development and characterization of Fe70Pd30 ferromagnetic shape memory splats

“…Seki et al [23] and Kang et al [25] found a strong increase of the transformation temperature with grain size. As the grain size R is expected to increase with T an according to R ¼ R 0 þ a$t$exp(ÀQ/k B T an ) (with the initial grain size R 0 , the activation energy for grain boundary movement Q and a proportionality factor a) the transformation temperature should increase in the same way.…”

Shape memory behaviour of Ti51.5Ni(48.5−x)Cux (x=23.4–37.3) thin films with submicron grain sizes

“…Accordingly, the decrease in the Ms temperature of the 27.6e37.3at.%Cu films with either decreasing annealing temperature or increasing Cu content is explained by the decrease of the grain size. Kang et al [19] investigated the relationship between grain size and martensitic transformation start temperature in Tie30Nie20Cu alloy ribbons crystallized at various temperatures and reported that the Ms temperature decreased from 317 to 308 K with decreasing grain size from 1.2 to 0.7 mm. Fig.…”