Tensile Deformation of Superelastic NiTi Wires in Wide Temperature and Microstructure Ranges

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61389005%3A_____%2F19%3A00503692" target="_blank" >RIV/61389005:_____/19:00503692 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/68378271:_____/19:00517463 RIV/68407700:21340/19:00337254

Výsledek na webu

<a href="https://doi.org/10.1007/s40830-018-00205-2" target="_blank" >https://doi.org/10.1007/s40830-018-00205-2</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1007/s40830-018-00205-2" target="_blank" >10.1007/s40830-018-00205-2</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Tensile Deformation of Superelastic NiTi Wires in Wide Temperature and Microstructure Ranges

Popis výsledku v původním jazyce

Superelastic NiTi wires were prepared from a single cold worked wire by various electropulse heat treatments. The wires having a wide range of virgin microstructures were subjected to tensile tests until rupture and cyclic superelastic tensile testing in a wide temperature range. The results were complemented by TEM observation of lattice defects created by superelastic cycling. It appeared that the yield stress depends significantly on the wire microstructure and less on the test temperature. The upper plateau stress varies with the microstructure through its effect on the Ms temperature and increases with increasing temperature in accord with the Clausius-Clapeyron equation up to a maximum temperature characteristic for each microstructure. The upper plateau strains exhibit pronounced maxima (12-18%) at test temperatures and microstructures (pulse times), at which the upper plateau stress approaches the yield stress. The instability of cyclic superelastic deformation was found to be inversely related to the difference between the yield stress and upper plateau stress. Cyclic deformation introduces dislocation slip in the microstructure of the cycled wire from the 3rd cycle and promotes formation of {114} austenite twins upon later cycling. These observations were explained by the activation of deformation twinning in oriented martensite and the stress induced B2 double right arrow B19 double right arrow B2(T) martensitic transformation in specific range of microstructures and temperatures. The ductility of the tested wires was observed to vary stepwise with microstructure from similar to 13 up to similar to 55% and gradually decreased with temperature increasing above 100 degrees C.

Název v anglickém jazyce

Tensile Deformation of Superelastic NiTi Wires in Wide Temperature and Microstructure Ranges

Popis výsledku anglicky

Superelastic NiTi wires were prepared from a single cold worked wire by various electropulse heat treatments. The wires having a wide range of virgin microstructures were subjected to tensile tests until rupture and cyclic superelastic tensile testing in a wide temperature range. The results were complemented by TEM observation of lattice defects created by superelastic cycling. It appeared that the yield stress depends significantly on the wire microstructure and less on the test temperature. The upper plateau stress varies with the microstructure through its effect on the Ms temperature and increases with increasing temperature in accord with the Clausius-Clapeyron equation up to a maximum temperature characteristic for each microstructure. The upper plateau strains exhibit pronounced maxima (12-18%) at test temperatures and microstructures (pulse times), at which the upper plateau stress approaches the yield stress. The instability of cyclic superelastic deformation was found to be inversely related to the difference between the yield stress and upper plateau stress. Cyclic deformation introduces dislocation slip in the microstructure of the cycled wire from the 3rd cycle and promotes formation of {114} austenite twins upon later cycling. These observations were explained by the activation of deformation twinning in oriented martensite and the stress induced B2 double right arrow B19 double right arrow B2(T) martensitic transformation in specific range of microstructures and temperatures. The ductility of the tested wires was observed to vary stepwise with microstructure from similar to 13 up to similar to 55% and gradually decreased with temperature increasing above 100 degrees C.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10302 - Condensed matter physics (including formerly solid state physics, supercond.)

Projekt

Výsledek vznikl pri realizaci vícero projektů. Více informací v záložce Projekty.

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2019

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Shape Memory and Superelasticity

ISSN

2199-384X

e-ISSN

—

Svazek periodika

5

Číslo periodika v rámci svazku

1

Stát vydavatele periodika

CH - Švýcarská konfederace

Počet stran výsledku

21

Strana od-do

42-62

Kód UT WoS článku

000461366700006

EID výsledku v databázi Scopus

2-s2.0-85062737814