A coupled kinetic Monte Carlo–finite element mesoscale model for thermoelastic martensitic phase transformations in shape memory alloys

Chen, Ying; Schuh, Christopher A.

doi:10.1016/j.actamat.2014.10.011

Cited by 28 publications

(19 citation statements)

References 69 publications

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“…In terms of thermodynamics, whenever B2 transform into B19 , the total free energy of the system (B2 + B19 ) increases as the developed internal strain increases the strain energy. Thus, to advance the transformation process, the temperature needs to decrease, and this reduces the total free energy of the system, thereby increasing the driving force on the remaining 2 Smart Materials Research B2 to transform into B19 [18,19]. Thus, to understand the martensitic phase transformation in NiTi SMA, it is very important to have knowledge of the evolution kinetics of various phases at the atomic level.…”

Section: Introductionmentioning

confidence: 99%

Atomistic Study on Size Effects in Thermally Induced Martensitic Phase Transformation of NiTi

Gur

Frantziskonis

2016

Smart Materials Research

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The atomistic study shows strong size effects in thermally induced martensitic phase transformation evolution kinetics of equiatomic NiTi shape memory alloys (SMAs). It is shown that size effects are closely related to the presence of free surfaces; thus, NiTi thin films and nanopillars are studied. Quasi-static molecular dynamics simulations for several cell sizes at various (constant) temperatures are performed by employing well-established interatomic potentials for NiTi. The study shows that size plays a crucial role in the evolution of martensite phase fraction and, importantly, can significantly change the phase transformation temperatures, which can be used for the design of NiTi based sensors, actuators, or devices at nano- to microscales. Interestingly, it is found that, at the nanometer scale, Richard’s equation describes very well the martensite phase fraction evolution in NiTi thin films and nanopillars as a function of temperature.

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Section: Introductionmentioning

confidence: 99%

Atomistic Study on Size Effects in Thermally Induced Martensitic Phase Transformation of NiTi

Gur

Frantziskonis

2016

Smart Materials Research

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“…The MT phenomenon in the case of x = 14.0 occurs via the application of an external uniaxial stress while not being cooling at zero stress and can be understood from the energy landscape for the austenite and martensite phases 46 . The free energies of the two phases are functions of temperature and stress and generally involve several sources (chemical free energy Δ G ch , mechanical energy E m , interfacial energy E i , surface energy E sf , stored elastic strain energy E el and frictional work E fr ).…”

Section: Resultsmentioning

confidence: 99%

“…The free energies of the two phases are functions of temperature and stress and generally involve several sources (chemical free energy Δ G ch , mechanical energy E m , interfacial energy E i , surface energy E sf , stored elastic strain energy E el and frictional work E fr ). The corresponding expression for the change in the Gibbs free energy (per unit volume) of a sample during transformation is shown as 46 :where γ i is the austenite/martensite interface energy per unit area, A i is the interfacial area, Δ γ sf is the difference in the surface energy per unit area, A sf is the specific surface area and E el is the average increment in elastic strain energy density. The frictional work E fr is irreversible and is positive in both transformation directions.…”

Section: Resultsmentioning

confidence: 99%

Elastocaloric effect and superelastic stability in Ni–Mn–In–Co polycrystalline Heusler alloys: hysteresis and strain-rate effects

Liu

2017

Sci Rep

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Controlling material hysteresis and working frequency variability are fundamentally important for refrigeration cycle efficiency and power density in solid-state cooling systems. For elastocaloric cooling, understanding the relationship between the width of the stress hysteresis and elastocaloric behaviour during superelastic cycles under varied strain rates is important. In this work, we report the effects of strain rate effects on the superelastic and elastocaloric responses in Ni45Mn50−xInxCo5 (x = 13.6–14.0 in at%) polycrystalline alloys. We observed a strong correlation between stress hysteresis and superelastic stability during mechanical cycling under increasing strain rates. Excellent transformation reversibility and stable superelastic responses are observed for x = 13.6 with a narrow hysteresis (49 MPa), whereas transformation irreversibility and dramatically deteriorated superelastic stability occur for x = 13.8, with a wide hysteresis (138 MPa). Furthermore, isothermal loading–unloading cycles under increasing and constant maximum applied stress were performed for the x = 13.6 samples, with a combination of low transformation stress and small transformation hysteresis. We suggest that a balance between transformation strain and hysteresis energy loss is fundamental to achieving a high coefficient of performance for elastocaloric materials.

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“…Following the fuzzy approach, RAO and QIU (2011) presented a methodology for the fuzzy analyses of nonlinear rotor-bearing systems along with numerical results that were presented to demonstrate the computational feasibility of the proposed approach. LARA-MOLINA, KOROISHI and STEFFEN JR. (2015) analyzed the dynamics of flexible rotors under uncertain parameters modeled as fuzzy and fuzzy random variables. CAVALINI JR et al (2015) evaluated the dynamic behavior of a flexible rotor with three rigid discs, supported by two fluid film bearings.…”

Section: Uncertainty Analysis Reviewmentioning

confidence: 99%

“…LARA-MOLINA, KOROISHI and STEFFEN JR. (2015) analyzed the dynamics of flexible rotors under uncertain parameters modeled as fuzzy and fuzzy random variables. CAVALINI JR et al (2015) evaluated the dynamic behavior of a flexible rotor with three rigid discs, supported by two fluid film bearings. The uncertainties were considered as affecting the oil viscosity and the radial clearance of both bearings that support the machine.…”

Section: Uncertainty Analysis Reviewmentioning

confidence: 99%

Fuzzy logic as a tool for uncertainty, robustness and reliability analyses of mechanical systems

Dourado¹

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I would like to express my sincere gratitude to my family, in special my mother for having provided to me the education basis that led me to all my accomplishments and for her encouragements to look for achievements that are more important. I am grateful to have a true angel in my life, my wife Mirella, thank you for sharing my dreams and for helping me to make our dreams come true. I thank also my colleges in the LMEst laboratory for the support you all assured to me during this journey, especially Prof. Dr. Aldemir Cavalini, whose contribution made this work possible. Thank you Prof. Dr. Leonardo Sanches for being a true friend along all these years. I would also like to express my sincere thanks to my advisor Prof. Valder Steffen Jr, who I learned to admire not only professionally but also as a person. I will consider myself fulfilled if I can achieve half of your accomplishments. A special thanks to the faculty and staff of FEMEC-UFU, and to my advisory committee members for their willingness on evaluating my thesis and contributing to its improvement. Finally, my sincere thanks to the financial support provided by the Brazilian research agencies CNPq, CAPES and FAPEMIG, and to the support of the INCT-EIE. I am also thankful to the companies CERAN, BAESA, ENERCAN, and Foz do Chapecó for the financial support through the R&D project Robust Modeling for the Diagnosis of Defects in Generating Units (02476-3108/2016). DOURADO, A. De P. Fuzzy Logic as a Tool for Uncertainty, Robustness and Reliability Analyses of Mechanical Systems. 2018. 89 pages.

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A coupled kinetic Monte Carlo–finite element mesoscale model for thermoelastic martensitic phase transformations in shape memory alloys

Cited by 28 publications

References 69 publications

Atomistic Study on Size Effects in Thermally Induced Martensitic Phase Transformation of NiTi

Atomistic Study on Size Effects in Thermally Induced Martensitic Phase Transformation of NiTi

Elastocaloric effect and superelastic stability in Ni–Mn–In–Co polycrystalline Heusler alloys: hysteresis and strain-rate effects

Fuzzy logic as a tool for uncertainty, robustness and reliability analyses of mechanical systems

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