Precipitation and thermal fatigue in Ni–Ti–Zr shape memory alloy thin films by combinatorial nanocalorimetry

McCluskey, Patrick; Zhao, Chunwang; Kfir, Ofer; Vlassak, Joost J.

doi:10.1016/j.actamat.2011.04.043

Cited by 34 publications

(9 citation statements)

References 36 publications

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“…Shape memory alloy (SMA) thin films, especially those based on NiTi, have been studied extensively over the last few decades because they are promising candidate materials for actuators in microelectromechanical systems (MEMS) (Ishida et al, 1995;König et al, 2011;McCluskey et al, 2011;Miyazaki and Ishida, 1994;Tomozawa et al, 2009;Wolf and Heuer, 1995). Several reviews of SMA process technology can be found in the literature (Fu et al, 2004;Ishida and Martynov, 2002;Winzek et al, 2004), while a detailed summary of the physical metallurgy of NiTi-based SMAs has been published by Otsuka and Ren (Otsuka and Ren, 2005).…”

Section: Introductionmentioning

confidence: 99%

Thickness and film stress effects on the martensitic transformation temperature in equi-atomic NiTi thin films

Wang

Vlassak

2015

Mechanics of Materials

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This paper presents the results of an experimental study of the transformation behavior and its thickness dependence of submicron Ni-50.5at %Ti thin films on substrates. Measurements were performed on thin films with a microstructure that consisted of pancake-like grains with aspect ratios in excess of 50:1 in order to minimize grain-imposed constraints. The effect of the residual stress on the martensite transformation behavior was evaluated by using different substrate materials covering a range of thermal expansion coefficients. If the thermal stress in the austenite phase exceeds ~300 MPa, the martensitic transformation occurs in a one-step process from B2→ B19', while films with a lower stress follow a two-step transformation of B 2 → Rphase →B19'. The slope of the stress-temperature curve during the B2→ B19' transformation is much larger than the equilibrium value and trends up with decreasing film thickness. For films less than 400 nm in thickness, the transformation temperature decreases rapidly with decreasing film thickness. Cross-sectional TEM analysis reveals small composition shifts in the immediate vicinity of the film interfaces, but not in the bulk of the films, ruling out any composition effects

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Section: Introductionmentioning

confidence: 99%

Thickness and film stress effects on the martensitic transformation temperature in equi-atomic NiTi thin films

Wang

Vlassak

2015

Mechanics of Materials

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“…10,11 This combinatorial technique can be used to study the kinetics of phase transformations and the effects of heat treatments as a function of composition and has been applied successfully to shape memory alloys and metallic glasses. [12][13][14] An important challenge in the nanocalorimetric study of multi-component materials systems is to assign the features in the calorimetric trace to the various physical events that take place as a function of temperature-phase transitions in multi-component systems lead to complex calorimetric signals. One possible approach to resolve this challenge consists of simultaneously performing x-ray diffraction (XRD) and calorimetry measurements.…”

Section: Introductionmentioning

confidence: 99%

Scanning AC nanocalorimetry combined with in-situ x-ray diffraction

Xiao

Gregoire

McCluskey

et al. 2013

Journal of Applied Physics

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Micromachined nanocalorimetry sensors have shown excellent performance for high-temperature and high-scanning rate calorimetry measurements. Here, we combine scanning AC nanocalorimetry with in-situ x-ray diffraction (XRD) to facilitate interpretation of the calorimetry measurements. Time-resolved XRD during in-situ operation of nanocalorimetry sensors using intense, high-energy synchrotron radiation allows unprecedented characterization of thermal and structural material properties. We demonstrate this experiment with detailed characterization of the melting and solidification of elemental Bi, In, and Sn thin-film samples, using heating and cooling rates up to 300 K/s. Our experiments show that the solidification process is distinctly different for each of the three samples. The experiments are performed using a combinatorial device that contains an array of individually addressable nanocalorimetry sensors. Combined with XRD, this device creates a new platform for high-throughput mapping of the composition dependence of solid-state reactions and phase transformations. V C 2013 AIP Publishing LLC.

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“…For instance, the nanocalorimetry sensor originally developed by Allen and coworkers can attain heating rates as large as 10 5 K/s, and has been used to perform very precise heat capacity measurements on nanoparticles [4,52] and ultrathin polymer films composition gradients, enabling high-throughput analysis of complex materials systems [7,23]. This combinatorial technique can be used to study the kinetics of phase transformations and the effects of heat treatments as a function of composition, and has been applied successfully to shape memory alloys and metallic glasses [29,55,56]. …”

Section: Introductionmentioning

confidence: 99%

Scanning AC Nanocalorimetry and Its Applications

Xiao

Vlassak

2016

Fast Scanning Calorimetry

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This thesis presents an AC nanocalorimetry technique that enables calorimetry measurements on very small quantities of materials over a wide range of scanning rates (from isothermal to 3×10^3 K/s), temperatures (up to 1200 K), and environments. Such working range bridges the gap between traditional scanning calorimetry of bulk materials and nanocalorimetry. The method relies on a micromachined nanocalorimeter with negligible thermal lags between heater, thermometer, and sample. The ability to perform calorimetry measurements over such a broad range of scanning rates makes it an ideal tool to characterize the kinetics of phase transformations, reactions at elevated temperatures or to explore the behavior of materials far from equilibrium. We By combining scanning DC and AC nano-calorimetry techniques, we study the nucleation behavior of undercooled liquid Bi at cooling rates ranging from 10^1 to 10^4 K/s. Upon initial melting, the Bi thin-film sample breaks up into isolated islands. The number of islands in a typical sample is sufficiently large that highly repeatable nucleation behavior is observed, despite the stochastic nature of the nucleation process.We establish a data reduction technique to evaluate the nucleation rate from DC and AC calorimetry results. The results show that the driving force for the nucleation of melted Bi is well described by classical nucleation theory over a wide range of cooling rates. The proposed technique provides a unique and efficient way to examine nucleation kinetics v with cooling rates over several orders of magnitude. The technique is quite general and can be used to evaluate reaction kinetics in other materials.Lastly, we apply the scanning AC nanocalorimetry technique to study solid-gas phase reactions by measuring the change in heat capacity of a sample during reaction. We apply this approach to evaluate the oxidation kinetics of thin-film samples of zirconium in air. The results confirm parabolic oxidation kinetics with an activation energy of 0.59±0.03 eV. The nano-calorimetry measurements were performed using a device that contains an array of micromachined nano-calorimeter sensors in an architecture designed for combinatorial studies. We demonstrate that the oxidation kinetics can be quantified using a single sample, thus enabling high-throughput mapping of the composition-dependence of the reaction rate.vi

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Precipitation and thermal fatigue in Ni–Ti–Zr shape memory alloy thin films by combinatorial nanocalorimetry

Cited by 34 publications

References 36 publications

Thickness and film stress effects on the martensitic transformation temperature in equi-atomic NiTi thin films

Thickness and film stress effects on the martensitic transformation temperature in equi-atomic NiTi thin films

Scanning AC nanocalorimetry combined with in-situ x-ray diffraction

Scanning AC Nanocalorimetry and Its Applications

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