Computational thermodynamics of the CoNiGa high temperature shape memory alloy system

Chari, Arpita; Dogan, E.; Talapatra, Anjana; Garay, Andres; Караман, И.; Arróyave, Raymundo

doi:10.1016/j.calphad.2013.12.005

Cited by 5 publications

(4 citation statements)

References 39 publications

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“…In Fig. 8, we show the predicted isothermal section (at 1200°C) in the Co-Ni-Ga system derived from the thermodynamic assessment by some of the present authors [74]. From the [62] isothermal section, it can be seen that there is a wide range of compositions in which the b (austenite) phase is in equilibrium with the ductile c phase.…”

Section: Optimal Microstructural Designmentioning

confidence: 87%

“…So far, we have seen how CALPHAD models can be used to understand the thermodynamics of the martensitic transformation in SMAs, the thermodynamics of point defects, the determination of metastable phase diagrams, as well as the design of complex microstructures. With regard to the application of CALPHAD methods to the understanding of phase stability in HTSMAs, there are a limited number of works [53,[76][77][78][79][80] that were not included in this section but that, in addition to the assessment of the Co-Ni-Ga HTSMA system by two of the present authors [74], constitute the bulk of the works on CALPHAD assessments of HTSMAs. When one considers that the phase stability in some of the most promising HTSMAs, such as those based on the NiTiHf and NiTiZr systems [1,7], remain unexplored within the CALPHAD framework, it is clear that there remains significant effort to be done.…”

Section: Optimal Microstructural Designmentioning

confidence: 99%

“…As such end members are seldom observed experimentally (they may be unstable or metastable at best), DFT calculations are the only means to obtain consistent thermodynamic descriptions. In recent years, DFT calculations and experiments have been used to obtain CALPHAD models of HTSMAs, including those belonging to the Co-Ni-Ga [74] and Fe-Ni-Ti [47,76] systems. Despite its promising potential, the combination of DFT and CALPHAD approaches to develop thermodynamically consistent descriptions of the phase stability in HTSMAs remains wide open.…”

Section: Ab Initio-based Thermodynamics Of Htsmasmentioning

confidence: 99%

See 2 more Smart Citations

Computational Thermodynamics and Kinetics-Based ICME Framework for High-Temperature Shape Memory Alloys

Arróyave

Talapatra

Johnson

et al. 2015

Shap. Mem. Superelasticity

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Over the last decade, considerable interest in the development of High-Temperature Shape Memory Alloys (HTSMAs) for solid-state actuation has increased dramatically as key applications in the aerospace and automotive industry demand actuation temperatures well above those of conventional SMAs. Most of the research to date has focused on establishing the (forward) connections between chemistry, processing, (micro)structure, properties, and performance. Much less work has been dedicated to the development of frameworks capable of addressing the inverse problem of establishing necessary chemistry and processing schedules to achieve specific performance goals. Integrated Computational Materials Engineering (ICME) has emerged as a powerful framework to address this problem, although it has yet to be applied to the development of HTSMAs. In this paper, the contributions of computational thermodynamics and kinetics to ICME of HTSMAs are described. Some representative examples of the use of computational thermodynamics and kinetics to understand the phase stability and microstructural evolution in HTSMAs are discussed. Some very recent efforts at combining both to assist in the design of HTSMAs and limitations to the full implementation of ICME frameworks for HTSMA development are presented.

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Section: Optimal Microstructural Designmentioning

confidence: 87%

Section: Optimal Microstructural Designmentioning

confidence: 99%

Section: Ab Initio-based Thermodynamics Of Htsmasmentioning

confidence: 99%

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Computational Thermodynamics and Kinetics-Based ICME Framework for High-Temperature Shape Memory Alloys

Arróyave

Talapatra

Johnson

et al. 2015

Shap. Mem. Superelasticity

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“…Na tabela 5 são mostrados os parâmetros de rede e índices de refinamento do pó de Co. Em acordo com a base de dados Crystmet, foram identificadas duas fases para o Co em pó, cúbica de face centrada (cfc) e hexagonais compacta (hc). A rede cristalina hc possui valores de células unitária a= 2,5071 Å, b= 2,5071 Å e c= 4,0695 Å [17,25] e cfc possui os valores de célula unitária a=b=c= 3,5447 Å [26,27,29]. Os resultados do Método de Rietveld apresentados na Tabela 5, mostra os valores dos parâmetros da rede cristalina hc e cfc para o Co e sua proximidade com os valores encontrados na literatura, provando assim a qualidade do refinamento.…”

Section: Método De Rietveldunclassified

Caracterização da matéria-prima com tamanho de partículas nanométricas utilizadas no processamento do compósito WC-10%Co

Batista¹,

Aguiar

Oliveira

et al. 2020

Matéria (Rio J.)

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RESUMO O compósito WC-10%Co também conhecido como Metal Duro de Carbeto de Tungstênico (WC) com Cobalto (Co) é um dos materiais mais produzidas pela indústria fabricante de metal duro, entretanto busca-se o melhor entendimento sobre o efeito de parâmetros de processo sobre as suas características estruturais, especialmente no que diz respeito à formação de fases metaestáveis – fases η. Neste trabalho, usamos o método de Rietveld aliado a difração de raios X (DRX), a microscopia eletrônica de varredura (MEV) e o Brunauer – Emmett – Teller (BET) para investigar a estrutura das matérias-primas utilizadas na produção de metal duro. Os tamanhos das partículas assim como as morfologias identificadas para os pós de WC e Co são reflexos do seu processo de fabricação que, introduzem tensões residuais para o pó de WC, a baixa cristalinidade e significante parcela de amorfo para o pó de Co. Estas características foram identificadas com a difração de raios X em comparação com o padrão de difração obtido e os bancos de dados cristalográficos. Após o processo de mistura dos pós foram quantificadas as fases e identificados os efeitos desse processo sobre as células unitárias de cada fase. Este trabalho mostra que a rota de caracterização empregada, com o uso do método de Rietveld, é eficiente para analisar a estrutura desses materiais durante seu processamento. Foi possível observar que o processo de mistura utilizando equipamento de moagem de alta energia promove alteração na densidade das células unitárias do WC “empurrando” átomos de Co para dentro de sua estrutura. Isso pode vir a acelerar o processo de dissolução de grande parte das partículas de WC durante a sinterização, contribuindo para a formação acentuada das fases metaestáveis eta – η, prejudicando o equilíbrio entre as propriedades mecânicas de dureza e tenacidade à fratura tornando a ferramenta ou peça muito dura e pouco tenaz.

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Heusler-type glass-coated microwires: Fabrication, characterization, and properties

Zhukov

Ipatov

Blanco

2020

Magnetic Nano- And Microwires

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Computational thermodynamics of the CoNiGa high temperature shape memory alloy system

Cited by 5 publications

References 39 publications

Computational Thermodynamics and Kinetics-Based ICME Framework for High-Temperature Shape Memory Alloys

Computational Thermodynamics and Kinetics-Based ICME Framework for High-Temperature Shape Memory Alloys

Caracterização da matéria-prima com tamanho de partículas nanométricas utilizadas no processamento do compósito WC-10%Co

Heusler-type glass-coated microwires: Fabrication, characterization, and properties

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