Behavio of Supeaplastically Extruded Cu-26wt%Zn–3.5wt%Al Shape Memory Alloy

1990 ◽  
Vol 196 ◽  
Author(s):  
Zheng Zhengyt ◽  
Zhcng Weijian ◽  
Lin Fuzeng ◽  
Chew Yingsheng
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory Alloys ◽  
Strain Rate ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Strain Rate Sensitivity ◽  
Rate Sensitivity ◽  
Heat Treated

ABSTRACTThe influence of superplastic extrusion on the microstructures and the shape memory effect of the Cu-Zn-Al shape memory alloys has been investigated. The shape memory alloy Cu-26%wt%Zn-3.5wt%Al is superplastio with an index of strain rate sensitivity n = 0.48 at 600°C, at a strain of . After extrusion under the superplastio condition the miorostruotures are improved and no cavities are observed. The superplastically extruded specimens of this alloy were heat-treated to obtain the shape memory effect. These specimens indicate that no deterioration of shape memory effect of the alloy is induced by the superplastio extrusion and the shape memory effect of the alloy is somewhat improved.

Cold Bending a Ni-Ti Shape Memory Alloy Wire

2015 ◽  
Vol 661 ◽  
pp. 98-104 ◽  
Author(s):  
Kuang-Jau Fann ◽  
Pao Min Huang
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Room Temperature ◽  
Aging Treatment ◽  
Treatment Temperature ◽  
Bending Test ◽  
Solution Treatment Temperature

Because of being in possession of shape memory effect and superelasticity, Ni-Ti shape memory alloys have earned more intense gaze on the next generation applications. Conventionally, Ni-Ti shape memory alloys are manufactured by hot forming and constraint aging, which need a capital-intensive investment. To have a cost benefit getting rid of plenty of die sets, this study is aimed to form Ni-Ti shape memory alloys at room temperature and to age them at elevated temperature without any die sets. In this study, starting with solution treatments at various temperatures, which served as annealing process, Ni-rich Ni-Ti shape memory alloy wires were bent by V-shaped punches in different curvatures at room temperature. Subsequently, the wires were aged at different temperatures to have shape memory effect. As a result, springback was found after withdrawing the bending punch and further after the aging treatment as well. A higher solution treatment temperature or a smaller bending radius leads to a smaller springback, while a higher aging treatment temperature made a larger springback. This springback may be compensated by bending the wires in further larger curvatures to keep the shape accuracy as designed. To explore the shape memory effect, a reverse bending test was performed. It shows that all bent wires after aging had a shape recovery rate above 96.3% on average.

scholarly journals Fabrication and Two-Way Deformation of Shape Memory Composite with SMA and SMP

2010 ◽  
Vol 638-642 ◽  
pp. 2189-2194 ◽  
Author(s):  
Hisaaki Tobushi ◽  
Shunichi Hayashi ◽  
Y. Sugimoto ◽  
K. Date
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Shape Memory Polymer ◽  
Bending Deformation ◽  
Heating And Cooling ◽  
Round Shape ◽  
Heat Treated ◽  
Shape Memory Composite

The shape memory composite (SMC) with shape memory alloy (SMA) and shape memory polymer (SMP) was fabricated, and the two-way bending deformation and recovery force were investigated. The results obtained can be summarized as follows. (1) Two kinds of SMA tapes which show the shape memory effect and superelasticity were heat-treated to memorize the round shape, respectively. The shape-memorized round SMA tapes were sandwiched between the SMP sheets, and the SMC belt was fabricated. (2) The two-way bending deformation with an angle of 56 degrees is observed during heating and cooling. (3) If the SMC belt is heated and cooled by keeping the form, recovery force increases during heating and decreases during cooling.

Conventional Plasticity Constitutive Model for Shape Memory Alloys

2011 ◽  
Vol 216 ◽  
pp. 469-473
Author(s):  
Hai Tao Li ◽  
Xiang He Peng
Keyword(s):  
Shape Memory Alloy ◽  
Constitutive Model ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Numerical Algorithm ◽  
Individual Behavior ◽  
Two Phase ◽  
The Individual

A two-phase constitutive model for shape memory alloys (SMAs) is proposed based on the fact that SMAs is dynamically composed of austenite and martensite. The behavior of SMAs is regarded as the dynamic combination of the individual behavior of each phase. This model can describe the main characteristics of SMAs, such as pseudoelasticity and shape memory effect. The corresponding numerical algorithm was also developed to describe the main features of shape memory alloy Au-47.5at.%Cd.

Investigation of the Kinetic of a Bainitic Reaction upon Heating in a CuAlNiMn and a CuAlNiMnFe Shape Memory Alloy

2013 ◽  
Vol 752 ◽  
pp. 3-9 ◽  
Author(s):  
Marton Benke ◽  
Valéria Mertinger ◽  
Peter Barkoczy
Keyword(s):  
Solid State ◽  
Kinetic Model ◽  
Shape Memory Alloy ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
One Stage ◽  
Shape Memory Behaviour ◽  
Memory Characteristics

The examination of solid state processes leading to the degradation of the shape memory behaviour is essential with respect to the suitability of shape memory alloys. Besides degradation processes occurring during relatively long periods of time called ageing, bainitic reactions that suddenly degrade the shape memory behaviour were also observed in many Cu-based shape memory alloys. The mechanisms and effects of the bainitic reactions on the shape memory characteristics were investigated in many Cu-based systems, but the kinetic of the reaction was not examined so far. In the present paper, an examination was carried out on a CuAlNiMn and a CuAlNiMnFe shape memory alloy to reveal what kinetic model describes the bainitic reaction occurring and thus completely destroying the shape memory effect during one stage of heating.

Unexpected Constrained Twin Hierarchy in Equiatomic Ru-Based High Temperature Shape Memory Alloy Martensite

2013 ◽  
Vol 738-739 ◽  
pp. 195-199 ◽  
Author(s):  
Philippe Vermaut ◽  
Anna Manzoni ◽  
Anne Denquin ◽  
Frédéric Prima ◽  
Richard Portier
Keyword(s):  
High Temperature ◽  
Martensitic Transformation ◽  
Shape Memory Alloy ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Martensitic Transformations ◽  
Single Transition

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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