Effect of the surface state of the Ti-Ni alloy products on the shape memory effect parameters

Прокошкин, С. Д.; Рыклина, Е. П.; Chernavina, A. A.; Abramov, V. Ya.; Krestnikov, N. S.

doi:10.1134/s003602950906010x

Cited by 2 publications

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References 3 publications

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“…4a and c). For the Ti-50.0 at.% Ni alloy, this tendency is retained up to high annealing temperatures [2]. It is interesting that the effect of a scale becomes the opposite for the Ti-50.7 at.% Ni alloy in the annealing temperature range 550-700 ºC: shape recovery in the samples coated with a scale begins at lower temperatures.…”

Section: Resultsmentioning

confidence: 94%

Study of Surface State Influence on Functional Poperties of Ti-Ni Alloys

Рыклина¹

2013

MSF

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Binary TiNi alloys containing 50.0 at.% Ni and 50.7 at.% Ni were tested under bending. Shape memory effect (SME) and two-way SME (TWSME) parameters were measured. Low-temperature thermomechanical treatment (LTMT) by drawing with true strain e ≈ 0.6 and post-deformation annealing (PDA) was performed in the temperature range 300600С for 0.3  1 hr permitted obtaining different types of initial austenite structure. The wires with 0.3 and 0.45 mm in diameter were studied. The curves of element distribution through the surface layer were graphed. The SME training procedure was carried out in bending with the constrained strain 0.7 and 8 %. Thickness, structure and element composition of the oxide film strongly depend on PDA regimes. In all cases titanium quantity in the boundary layer correlates with the oxygen quantity, diffused from the surface. Evidently, it is caused by their chemical reaction and oxide formation. Nickel atoms remain in uncombined state, and their migration is directed from the surface deep into the sample. LTMT permits decreasing the film thickness more than by 10 times. Surface state strongly affects all studied parameters: characteristic temperatures, recovery strain and TWSME value. Increasing of wire diameter from 0.3 to 0.45 mm leads to significant changes of studied parameters. Forecasting of said influence is difficult because of its ambiguity. Therefore, the oxide film must be eliminated by etching in order to obtain the reliable results

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Section: Resultsmentioning

confidence: 94%

Study of Surface State Influence on Functional Poperties of Ti-Ni Alloys

Рыклина¹

2013

MSF

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Influence of heat treatment on thermokinetic EMF during reverse phase transition in titanium nickelide

Petrova-Burkina

Рубаник

et al. 2020

Vescì Akademìì navuk Belarusì. Seryâ fizika-tehničnyh navuk

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The effect of duration and annealing temperature in the range of 400–800 °C on the thermokinetic EMF value in titanium nickelide, the composition of which is close to the equi-atomic one, at a reverse phase transition was investigated. Thermokinetic EMF was measured directly using a digital millivoltmeter MNIPI V7-72. The phase and elemental composition of the alloy and the kinetics of thermoelastic phase transformations have been checked by X-ray diffraction and calorimetric studies, and X-ray microanalysis. Annealing at temperatures of 500 and 800 °C leads to an increase in the thermokinetic EMF value from 0.22 to 0.25 mV. Removal of the oxide layer from the sample surface annealed at 700 °C for 0.5 h leads to an increase in the thermokinetic EMF value from 0.22 to 0.26 mV for the 1-st thermal cycle. It was found that thermal cycling causes a decrease in the thermokinetic EMF values down to 0.98 mV for the 20th thermal cycle for the samples without an oxide layer and to 0.3 mV for the samples with an oxide layer, respectively. With the increase in annealing time up to 20 h at 700 °C, the decrease in the thermokinetic emf value to 0.16 mV was observed. The thermokinetic EMF value after heat treatment is associated with changes in the physical and mechanical properties of the alloy and characterized by a shift of the characteristic temperatures of the phase transition. The research results are important for understanding the physics of thermoelectric phenomena in shape memory alloys during nonstationary heating and can be used both to control the homogeneity of their physical and mechanical properties and to design smart actuators and sensors, mechanisms of control systems.

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Effect of the surface state of the Ti-Ni alloy products on the shape memory effect parameters

Cited by 2 publications

References 3 publications

Study of Surface State Influence on Functional Poperties of Ti-Ni Alloys

Study of Surface State Influence on Functional Poperties of Ti-Ni Alloys

Influence of heat treatment on thermokinetic EMF during reverse phase transition in titanium nickelide

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