Indentation behavior of pseudoelastic TiNi alloy

Liu, R.; Li, D.Y.; Xie, Yi; Llewellyn, R.; Hawthorne, H.M.

doi:10.1016/s1359-6462(99)00199-2

Cited by 128 publications

(60 citation statements)

References 11 publications

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“…Hardness and elastic behavior of the oxide scales were determined from the indentation curves and each reported value was an average of 50 measurements. The elastic behavior was evaluated using the ratio (g) of elastic deformation energy (W e ) to the total deformation energy (W tot ) [20]. W tot is represented by the area enclosed by the loading curve and the maximum penetration depth while W e is represented by the area enclosed between the maximum penetration depth and the unloading curve.…”

Section: Resultsmentioning

confidence: 99%

A Further Study of the Beneficial Effects of Yttrium on Oxide Scale Properties and High-Temperature Wear of Stellite 21

Radu

2008

Tribol Lett

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Alloying yttrium to Co-based alloys has been proven to considerably improve their oxide scales that play an important role in resisting wear at elevated temperatures. In addition to the formation of Y 2 O 3 phase in the oxide scale, the yttrium addition may also change the oxidation mechanism, which could be responsible for many benefits of yttrium to the wear resistance of this alloy at elevated temperatures. In this study, the effect of yttrium on the oxidation behavior of Stellite 21 alloy was investigated and correlated to the changes in microstructure and improvement in properties of the oxide scale formed at 600°C which in turn improved high-temperature wear behavior.

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Section: Resultsmentioning

confidence: 99%

A Further Study of the Beneficial Effects of Yttrium on Oxide Scale Properties and High-Temperature Wear of Stellite 21

Radu

2008

Tribol Lett

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“…The η ratio which is a measure of pseudoelasticity was calculated according to the method proposed in Ref. [12].…”

Section: Methodsmentioning

confidence: 99%

Challenges of Using Elemental Nickel and Titanium Powders for the Fabrication of Monolithic NiTi Parts

Farvizi¹

2017

Archives of Metallurgy and Materials

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Due to its interesting properties and wide applications in different industries, fabrication of monolithic NiTi with cost-effective methods is an important and attractive issue. One of the economic ways to fabricate NiTi is employing elemental nickel and titanium powders. In this study, effects of using elemental powders as a precursor on the microstructure and mechanical properties of HIP-consolidated NiTi samples will be explored. The result of XRD analysis showed that after HIP process an interwoven structure which consists of NiTi 2 , Ni 3 Ti and B2-B19′ NiTi evolves. The formation of NiTi 2 /Ni 3 Ti intermetallics is thermodynamically favored which affects different aspects of this alloy: (i) it alters martensitic transformation temperatures; (ii) restricts essential properties of this alloy such as PE and SME, (iii) increases hardness, and (iv) yields to premature fracture at small strains during tensile tests.

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“…In fact, the latter is expected to play a significant role in the indentation response of SMAs, as this takes place in the indentation region due to the presence of highly localized stresses. As a consequence, well known contact mechanics theories for conventional metals cannot be directly applied to SMAs and work has been carried out, in recent years, to understand better the effects of microstructural transitions on the indentation response of both thin films [3][4][5][6][7][8] and bulk specimens [9][10][11][12][13][14][15]. These studies revealed marked effects of material composition, as well as the thermo-mechanical treatments carried out during material processing, on the indentation response of SMAs.…”

Section: Introductionmentioning

confidence: 99%

Indentation response of a NiTi shape memory alloy: modeling and experiments

Maletta

Furgiuele

Sgambitterra

et al. 2012

Frattura Ed Integrità Strutturale

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ABSTRACT. The indentation response of a pseudoelastic nickel-titanium based shape memory alloy (SMA) has been analyzed. Indentation tests have been carried out at room temperature using a spherical diamond tip and indentation loads in the range 50-500 mN in order to promote a large stress-induced transformation zone in the indentation region and, consequently, to avoid local effects due to microstructural variations. The measured load-displacement data have been analyzed to obtain information on the pseudoelastic response of the alloy. To aid this analysis numerical simulations were performed, by using a commercial finite element (FE) software code and a special constitutive model for SMAs, so as to understand better the microstructural evolution occurring during the indentation process. Finally, the FE model has been used to analyze the effects of temperature on the indentation response of the alloy. This analysis revealed a marked variation of both the maximum and residual penetration depths with increasing test temperature. SOMMARIO.Nel presente lavoro è stata analizzata la risposta all'indentazione di una lega a memoria di forma (SMA -Shape Memory Alloy) a base di nickel e titanio. In particolare, sono state eseguite prove di indentazione mediante l'utilizzo di un indentatore sferico e per livelli di carico compresi tra 50 e 500 mN, al fine di favorire la formazione di zone di trasformazione ampie e, pertanto, evitare effetti locali dovuti a variazioni microstrutturali. Le curve carico-spostamento sono state analizzate al fine di ottenere informazioni utili per la comprensione del comportamento pseudoelastico della lega. A tale scopo, sono state condotte analisi numeriche, utilizzando un software commerciale agli elementi finiti, per meglio comprendere i cambiamenti microstrutturali, che avvengono durante il processo di indentazione. Infine, il modello numerico è stato utilizzato per analizzare l'effetto della temperatura sulla risposta all'indentazione delle SMAs. I risultati hanno mostrato una marcata variazione della profondità di penetrazione e della profondità residua al variare della temperatura.

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Indentation behavior of pseudoelastic TiNi alloy

Cited by 128 publications

References 11 publications

A Further Study of the Beneficial Effects of Yttrium on Oxide Scale Properties and High-Temperature Wear of Stellite 21

A Further Study of the Beneficial Effects of Yttrium on Oxide Scale Properties and High-Temperature Wear of Stellite 21

Challenges of Using Elemental Nickel and Titanium Powders for the Fabrication of Monolithic NiTi Parts

Indentation response of a NiTi shape memory alloy: modeling and experiments

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