Effects of Temperature on Serrated Flows of Al0.5CoCrCuFeNi High-Entropy Alloy

Chen, Shuying; Xie, Xie; Chen, Bilin; Qiao, J.W.; Zhang, Yong; Ren, Yang; Dahmen, Karin A.; Liaw, Peter K.

doi:10.1007/s11837-015-1580-8

Cited by 46 publications

(27 citation statements)

References 41 publications

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“…8a, 8b and 8c. Other work has shown that dislocations will be pinned by segregation during the mechanical deformation if the solute atoms are mobile enough to segregate to the dislocations, similar to Cottrell atmospheres in carbon steels [61] . The present work has shown that the mobile species have precipitated as Ni-Al nano-particles, which combined with the more homogeneous deformation produced by such particles reduces the tendency for such flow serrations.…”

Section: Apt Results and Deformation Behaviormentioning

confidence: 90%

High-entropy Al0.3CoCrFeNi alloy fibers with high tensile strength and ductility at ambient and cryogenic temperatures

et al. 2017

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High-entropy alloys (HEAs) are multi-component systems based on novel alloy composition designs with entropy maximization. They feature an array of unique mechanical properties when compared with traditional alloys. In this study, HEA fibers with diameters ranging from 1-3.15 mm in diameter, with the composition of Al 0.3 CoCrFeNi (atomic percent, at. %), were successfully fabricated by hot-drawing, followed by microstructural characterization using scanning-electron microscopy (SEM) and transmission-electron microscopy (TEM). The compositional variations within and between fibers were determined using energy-dispersive X-ray spectroscopy in TEM along with atomic-probe tomography (APT). These analyses revealed a homogeneous face-centered cubic (FCC) structure in the as-cast material, while post processing (e.g., forging and wire drawing) produced nanosized B2 *Text only Click here to download Text only: Text.docx Click here to view linked References

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Section: Apt Results and Deformation Behaviormentioning

confidence: 90%

High-entropy Al0.3CoCrFeNi alloy fibers with high tensile strength and ductility at ambient and cryogenic temperatures

et al. 2017

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“…The Al 0.5 CrFeCoNiCu HEA shows the directional transformation of serrations from upward serrations at 400-500 C to downward serrations at 600 C (shown in Figure 10). [169] The critical strain for the onset of serrations in this alloy shows normal behavior, that is, the critical strain value decreases with increasing temperature. It is speculated that the dynamic strain aging (DSA) causes serration in this alloy.…”

Section: Mechanical Properties At Elevated Temperaturementioning

confidence: 83%

“…The optimum condition for thermomechanical processing of homogenized sample was identified as 945-965 C and 10 À1.7 -10 À1.1 s À1 . Chen et al [169] observed a change in crystal structure in Al 0.5 CrFeCoNiCu HEA after compression test in the temperature range of 400-600 C at a strain rate of 5 Â 10 À5 s À1 . A single FCC phase and the mixture of FCC and BCC phases were observed for the samples tested at 400-500 C and 600 C, respectively.…”

Section: Mechanical Properties At Elevated Temperaturementioning

confidence: 99%

“…[170] The serrations in flow behavior have been reported for few HEAs. [169,[171][172][173][174] Serrations, in general, can occur in flow curve during plastic deformation due to many factors, and one of them is the interaction between solute atoms and dislocations. The Al 0.5 CrFeCoNiCu HEA shows the directional transformation of serrations from upward serrations at 400-500 C to downward serrations at 600 C (shown in Figure 10).…”

Section: Mechanical Properties At Elevated Temperaturementioning

confidence: 99%

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High‐Entropy Alloys: Potential Candidates for High‐Temperature Applications – An Overview

2017

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Multi-principal elemental alloys, commonly referred to as high-entropy alloys (HEAs), are a new class of emerging advanced materials with novel alloy design concept. Unlike the design of conventional alloys, which is based on one or at most two principal elements, the design of HEA is based on multi-principal elements in equal or near-equal atomic ratio. The advent of HEA has revived the alloy design perception and paved the way to produce an ample number of compositions with different combinations of promising properties for a variety of structural applications. Among the properties possessed by HEAs, sluggish diffusion and strength retention at elevated temperature have caught wide attention. The need to develop new materials for high-temperature applications with superior high-temperature properties over superalloys has been one of the prime concerns of the high-temperature materials research community. The current article shows that HEAs have the potential to replace Ni-base superalloys as the next generation hightemperature materials. This review focuses on the phase stability, microstructural stability, and high-temperature mechanical properties of HEAs. This article will be highly beneficial for materials science and engineering community whose interest is in the development and understanding of HEAs for high-temperature applications.

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“…Recently, it was reported that ternary and quaternary alloys can also be regarded as HEAs, such as ZrNbHf 16 and WNbMoTa 17 . Specifically, with a large number of elements, HEAs soon form solid solutions with structures, including body-centered-cubic (BCC) structure 3 17 18 19 , face-centered-cubic (FCC) structure 3 20 21 22 , or hexagonal-closed-packed (HCP) structure 3 23 24 25 , rather than complicated intermetallic compounds, which could be attributed to the large configurational entropy. In addition, HEAs possess superior properties, such as the enhanced yield strength 26 , good resistance to wear and fatigue 15 22 27 and corrosion 28 29 , remarkable fracture-toughness at cryogenic temperature 4 , and excellent properties at elevated temperatures 30 .…”

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Self-Similar Random Process and Chaotic Behavior In Serrated Flow of High Entropy Alloys

Chen

Ren

et al. 2016

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The statistical and dynamic analyses of the serrated-flow behavior in the nanoindentation of a high-entropy alloy, Al0.5CoCrCuFeNi, at various holding times and temperatures, are performed to reveal the hidden order associated with the seemingly-irregular intermittent flow. Two distinct types of dynamics are identified in the high-entropy alloy, which are based on the chaotic time-series, approximate entropy, fractal dimension, and Hurst exponent. The dynamic plastic behavior at both room temperature and 200 °C exhibits a positive Lyapunov exponent, suggesting that the underlying dynamics is chaotic. The fractal dimension of the indentation depth increases with the increase of temperature, and there is an inflection at the holding time of 10 s at the same temperature. A large fractal dimension suggests the concurrent nucleation of a large number of slip bands. In particular, for the indentation with the holding time of 10 s at room temperature, the slip process evolves as a self-similar random process with a weak negative correlation similar to a random walk.

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Effects of Temperature on Serrated Flows of Al0.5CoCrCuFeNi High-Entropy Alloy

Cited by 46 publications

References 41 publications

High-entropy Al0.3CoCrFeNi alloy fibers with high tensile strength and ductility at ambient and cryogenic temperatures

High-entropy Al0.3CoCrFeNi alloy fibers with high tensile strength and ductility at ambient and cryogenic temperatures

High‐Entropy Alloys: Potential Candidates for High‐Temperature Applications – An Overview

Self-Similar Random Process and Chaotic Behavior In Serrated Flow of High Entropy Alloys

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