High-temperature shape memory effect and the B2-L10 thermoelastic martensitic transformation in Ni-Mn intermetallics

2013 ◽  
Vol 58 (6) ◽  
pp. 878-887 ◽  
Author(s):  
V. G. Pushin ◽  
N. N. Kuranova ◽  
E. B. Marchenkova ◽  
E. S. Belosludtseva ◽  
V. A. Kazantsev ◽  
...  
2001 ◽  
Vol 291 (2-3) ◽  
pp. 175-183 ◽  
Author(s):  
A.A. Cherechukin ◽  
I.E. Dikshtein ◽  
D.I. Ermakov ◽  
A.V. Glebov ◽  
V.V. Koledov ◽  
...  

2008 ◽  
Vol 138 ◽  
pp. 399-406 ◽  
Author(s):  
Xiang Long Meng ◽  
Yu Dong Fu ◽  
Wei Cai ◽  
J.X. Zhang ◽  
Qing Fen Li ◽  
...  

The martensitic transformation behavior and shape memory effect (SME) have been investigated in a Ni-rich Ti29.6Ni50.4Hf20 high temperature shape memory alloy (SMA) in the present study. After aging, the transformation temperatures of Ti29.6Ni50.4Hf20 alloy increase obviously due to the precipitation of (Ti,Hf)3Ni4 particles. And the transformation sequence changes from one-step to two-step. When the experimental alloy is aged at different temperatures for 2h, the transformation temperatures increase rapidly with increasing the aging temperature and then change slightly with further increasing the aging temperature. Most of the martensite variants preferentially oriented in the aged Ti29.6Ni50.4Hf20 alloy. The aged Ti29.6Ni50.4Hf20 alloy shows the better thermal stability of transformation temperatures than the solution-treated one because the precipitates depress the introduction of defects during thermal cycling. In addition, the proper aged Ti29.6Ni50.4Hf20 alloy also shows the larger SME than the solution-treated one since the precipitates strengthen the matrix strongly.


Author(s):  
А.Б. Тохметова ◽  
Н.Г. Ларченкова ◽  
Е.Ю. Панченко ◽  
Ю.И. Чумляков

The effects of stress-induced martensite aging (SIM-aging) along the [110]B2-direction on the thermoelastic martensitic transformation in Ni49Fe18Ga27Co6 single crystals were investigated. It was experimentally established that the effective regime of SIM-aging (at T = 423 K, 1 h under a compressive stress 450 MPa) results in a stabilization of stress-induced martensite and inducing the tensile two-way shape memory effect with reversible strain of +9.0 (± 0.3) % along the [001]B2-direction which is the perpendicular to the SIM-aging axis. Maximum work output of Wmax = 0.14 J/g (1125 kJ/m3) that can be realized using the two-way shape memory effect was obtained.


2013 ◽  
Vol 738-739 ◽  
pp. 195-199 ◽  
Author(s):  
Philippe Vermaut ◽  
Anna Manzoni ◽  
Anne Denquin ◽  
Frédéric Prima ◽  
Richard Portier

Among the different systems for high temperature shape memory alloys (SMA’s), equiatomic RuNb and RuTa alloys demonstrate both shape memory effect (SME) and MT temperatures above 800°C. Equiatomic compounds undergo two successive martensitic transformations, β (B2) → β’ (tetragonal) → β’’ (monoclinic), whereas out of stoechiometry alloys exhibit a single transition from cubic to tetragonal. In the case of two successive martensitic transformations, we expect to have a finer microstructure of the second martensite because it is supposed to develop inside the smallest twin elements of the former one. In equiatomic Ru-based alloys, if the first martensitic transformation is “normal”, the second one gives different unexpected microstructures with, for instance, twins with a thickness which is larger than the smallest spacing between twin variants of the first martensite. In fact, the reason for this unexpected hierarchy of the twins size is that the second martensitic transformation takes place in special conditions: geometrically, elastically and crystallographically constrained.


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