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https://doi.org/10.15255/KUI.2013.016

Shape Memory Alloys (Part I): Significant Properties

I. Ivanić ; Faculty of Metallurgy, University of Zagreb, Sisak, Croatia
M. Gojić ; Faculty of Metallurgy, University of Zagreb, Sisak, Croatia
S. Kožuh ; Faculty of Metallurgy, University of Zagreb, Sisak, Croatia

Puni tekst: hrvatski, pdf (1 MB) str. 323-330 preuzimanja: 453* citiraj
APA 6th Edition
Ivanić, I., Gojić, M. i Kožuh, S. (2014). Slitine s prisjetljivosti oblika (I. dio): najznačajnija svojstva. Kemija u industriji, 63 (9-10), 323-330. https://doi.org/10.15255/KUI.2013.016
MLA 8th Edition
Ivanić, I., et al. "Slitine s prisjetljivosti oblika (I. dio): najznačajnija svojstva." Kemija u industriji, vol. 63, br. 9-10, 2014, str. 323-330. https://doi.org/10.15255/KUI.2013.016. Citirano 23.10.2019.
Chicago 17th Edition
Ivanić, I., M. Gojić i S. Kožuh. "Slitine s prisjetljivosti oblika (I. dio): najznačajnija svojstva." Kemija u industriji 63, br. 9-10 (2014): 323-330. https://doi.org/10.15255/KUI.2013.016
Harvard
Ivanić, I., Gojić, M., i Kožuh, S. (2014). 'Slitine s prisjetljivosti oblika (I. dio): najznačajnija svojstva', Kemija u industriji, 63(9-10), str. 323-330. https://doi.org/10.15255/KUI.2013.016
Vancouver
Ivanić I, Gojić M, Kožuh S. Slitine s prisjetljivosti oblika (I. dio): najznačajnija svojstva. Kemija u industriji [Internet]. 2014 [pristupljeno 23.10.2019.];63(9-10):323-330. https://doi.org/10.15255/KUI.2013.016
IEEE
I. Ivanić, M. Gojić i S. Kožuh, "Slitine s prisjetljivosti oblika (I. dio): najznačajnija svojstva", Kemija u industriji, vol.63, br. 9-10, str. 323-330, 2014. [Online]. https://doi.org/10.15255/KUI.2013.016

Sažetak
Shape memory alloys (SMAs) belong to a group of functional materials with the unique property of “remembering” the shape they had before pseudoplastic deformation. Such an effect is based on crystallographic reversible thermo-elastic martensitic transformation. There are two crystal phases in SMAs: the austenite phase (stable at high temperature) and the martensite phase (stable at low temperature).
Austenite to martensite phase transformation can be obtained by mechanical (loading) and thermal methods (heating and cooling). During martensitic transformation, no diffusive process is involved, only inelastic deformation of the crystal structure. When the shape memory alloy passes through the phase transformation, the alloy transforms from high ordered phase (austenite) to low ordered phase (martensite). There are two types of martensite transformations. First is temperature-induced martensite, which is also called self-accommodating (twinned) martensite. The second is stress-induced martensite, also called detwinned martensite. The entire austenite to martensite transformation cycle can be described with four characteristic temperatures: Ms – martensite start temperature, Mf – martensite finish temperature, As – austenite start temperature, and Af – austenite finish temperature. The main factors influencing transformation temperatures are chemical composition, heat treatment procedure, cooling speed, grain size, and number of transformation cycles.
As a result of martensitic transformation in SMAs, several thermomechanical phenomena may occur: pseudoelasticity, shape memory effect (one-way and two-way SME) and rubber-like behavior. Pseudoelasticity occurs when the SMA is subjected to a mechanical loading at a constant temperature above Af. The second thermomechanical behaviour that can be observed in SMA is the shape memory effect (SME), mainly one-way SME, which is the most commonly used SME. When the sample is subjected to a mechanical loading, the stress reaches a critical value and the transformation of twinned martensite into detwinned martensite begins and finishes when the loading process is finished. When the loading-unloading process is finished, the SMA presents a residual strain recoverable by alloy heating, which induces the reverse phase transformation. As a result, the alloy recovers to its original shape.
In this paper, a review of thermomechanical properties of shape memory alloys and general characteristics of martensite transformations is shown.

Ključne riječi
Shape memory alloy; martensite transformation; austenite; pseudoelasticity; shape memory effect

Hrčak ID: 126394

URI
https://hrcak.srce.hr/126394

[hrvatski]

Posjeta: 601 *