| 1. |
- Jiao, Wenna, et al.
(author)
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Eutectic High-Entropy Alloys
- 2022
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In: Materials Horizons: From Nature to Nanomaterials. - Singapore : Springer Nature Singapore. - 2524-5392 .- 2524-5384. ; , s. 53-90
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Book chapter (other academic/artistic)abstract
- Eutectic high-entropy alloys (EHEAs), as a subclass of high-entropy alloys (HEAs), exhibit various excellent mechanical, physical, and anti-corrosion properties as well as excellent castability, which are becoming one of the research frontiers in the metal alloy field. EHEAs combine nicely the unique advantages of eutectic alloys and HEAs, with in-situ formed composite structure containing multi-principal components during the solidification process. Since the first report of EHEAs in 2014, plenty of investigations have been made on the topic, resulting in dozens of promising candidate EHEAs for future applications. In this chapter, the recent research advances in EHEAs were summarized, to comprehensively present the historical development, current situation, and future aspects of EHEAs. The concept of EHEAs was firstly introduced, which was proposed based on the special solidification microstructure of eutectic alloys. The excellent mechanical performance in directly cast EHEAs inspired rapid developments on this topic. Then, several alloy design methods were introduced, for the efficient prediction of new EHEA systems. Meanwhile, the deformation behavior and mechanisms have been thoroughly investigated for a mechanistic understanding of the superior mechanical properties of EHEAs, and they were summarized here. Finally, the potential applications and future developments of EHEAs were suggested as a concluding remark.
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| 2. |
- Lu, Yiping, et al.
(author)
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A new strategy to design eutectic high-entropy alloys using mixing enthalpy
- 2017
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In: Intermetallics. - : Elsevier BV. - 0966-9795. ; 91, s. 124-128
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Journal article (peer-reviewed)abstract
- Although eutectic high entropy alloys (EHEAs) display homogeneously fine microstructure, excellent castability and promising industrial application potential, how to design eutectic compositions in high entropy alloys (HEAs) remains to be challenging. Here, a novel strategy, specifically, through calculation of mixing enthalpy, was used to locate eutectic compositions in HEAs. As a proof of this concept, a series of EHEAs were located and prepared following the mixing enthalpy method. Using this new strategy, eutectic compositions can be designed conveniently, once one can classify elements into two different groups. This new alloy design strategy can be readily adapted to locate new EHEAs.
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| 3. |
- Lu, Yiping, et al.
(author)
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Directly cast bulk eutectic and near-eutectic high entropy alloys with balanced strength and ductility in a wide temperature range
- 2017
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In: Acta Materialia. - : Elsevier BV. - 1359-6454. ; 124, s. 143-150
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Journal article (peer-reviewed)abstract
- High entropy alloys (HEAs) usually possess weak liquidity and castability, and considerable compositional inhomogeneity, mainly because they contain multiple elements with high concentrations. As a result, large-scale production of HEAs by casting is limited. To address the issue, the concept of eutectic high entropy alloys (EHEAs) was proposed, which has led to some promise in achieving good quality industrial scale HEAs ingots, and more importantly also good mechanical properties. In the practical large-scale casting, the actual composition of designed EHEAs could potentially deviate from the eutectic composition. The influence of such deviation on mechanical properties of EHEAs is important for industrial production, which constitutes the topic of the current work. Here we prepared industrial-scale HEAs ingots near the eutectic composition: hypoeutectic alloy, eutectic alloy and hypereutectic alloy. Our results showed that the deviation from eutectic composition does not significantly affect the mechanical properties, castability and the good mechanical properties of EHEAs can be achieved in a wide compositional range, and at both room and cryogenic temperatures. Our results suggested that EHEAs with simultaneous high strength and high ductility, and good liquidity and castability can be readily adapted to large-scale industrial production. The deformation behavior and microstructure evolution of the eutectic and near-eutectic HEAs were thoroughly studied using a combination of techniques, including strain measurement by digital image correlation, in-situ synchrotron X-ray diffraction, and transmission electron microscopy. The wavy strain distribution and the therefore resulted delay of necking in EHEAs were reported for the first time.
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| 4. |
- Lu, Yiping, et al.
(author)
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Preparing bulk ultrafine-microstructure high-entropy alloys: Via direct solidification
- 2018
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In: Nanoscale. - : Royal Society of Chemistry (RSC). - 2040-3372 .- 2040-3364. ; 10:4, s. 1912-1919
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Journal article (peer-reviewed)abstract
- In the past three decades, nanostructured (NS) and ultrafine-microstructure (UFM) materials have received extensive attention due to their excellent mechanical properties such as high strength. However, preparing low-cost and bulk NS and UFM materials remains to be a challenge, which limits their industrial applications. Here, we report a new strategy to prepare bulk UFM alloys via the direct solidification of high-entropy alloys (HEAs). As a proof of concept, we designed AlCoCr x FeNi (1.8 ≤ x ≤ 2.0) HEAs and achieved a complete UFM in bulk materials. The compositional requirements for obtaining the formation of the UFM are highly demanding, necessitating the coupling of near eutectic alloy composition and the high temperature decomposition of supersaturated primary and secondary phases. Our strategy provides a low-cost and highly efficient method to prepare bulk UFM alloys, with great potential to accelerate the engineering application of these materials.
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| 5. |
- Lu, Yiping, et al.
(author)
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Promising properties and future trend of eutectic high entropy alloys
- 2020
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In: Scripta Materialia. - : Elsevier BV. - 1359-6462. ; 187, s. 202-209
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Journal article (peer-reviewed)abstract
- Eutectic high-entropy alloys (EHEAs), as a sub-group of high-entropy alloys (HEAs), are becoming a new research hotspot in the metallic materials community because of their excellent castability, fine and uniform microstructures even in the as-cast state, high strength, and good ductility. Some of the EHEAs have shown promising potentials for industrial applications. Here, the history, interesting solidification microstructure and mechanical properties, and the design strategy of EHEAs are reviewed, and their future prospects are outlined.
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| 6. |
- Ning, Zhijun, et al.
(author)
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Photovoltage Improvement for Dye-Sensitized Solar Cells via Cone-Shaped Structural Design
- 2009
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In: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 113:23, s. 10307-10313
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Journal article (peer-reviewed)abstract
- In this article, three truexene-based dyes with 2-cyanoacrylic acid as acceptor and starburst triarylamine as donor (S5, S6, and S7) were conveniently synthesized and used for dye-sensitized solar cells (DSSCs). A compact sensitizer layer is molecular interfacially engineered on the TiO2 surface via cone-shaped sensitizers. As a result, the approach of the electrolyte to the TiO2 surface is blocked significantly by the compact sensitizer layer formed and the charge recombination in the DSSCs is proved to be retarded effectively. The monochromatic incident photon-to-current conversion efficiency of these sensitizers is near 90%. In addition, S7-sensitized solar cells yield an open-circuit voltage of 752 mV and it fill factor of 0.70, which are even higher than those of N719 under the same conditions.
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| 7. |
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The Seventeenth Data Release of the Sloan Digital Sky Surveys : Complete Release of MaNGA, MaStar, and APOGEE-2 Data
- 2022
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In: Astrophysical Journal Supplement Series. - : Institute of Physics (IOP). - 0067-0049 .- 1538-4365. ; 259:2
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Journal article (peer-reviewed)abstract
- This paper documents the seventeenth data release (DR17) from the Sloan Digital Sky Surveys; the fifth and final release from the fourth phase (SDSS-IV). DR17 contains the complete release of the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey, which reached its goal of surveying over 10,000 nearby galaxies. The complete release of the MaNGA Stellar Library accompanies this data, providing observations of almost 30,000 stars through the MaNGA instrument during bright time. DR17 also contains the complete release of the Apache Point Observatory Galactic Evolution Experiment 2 survey that publicly releases infrared spectra of over 650,000 stars. The main sample from the Extended Baryon Oscillation Spectroscopic Survey (eBOSS), as well as the subsurvey Time Domain Spectroscopic Survey data were fully released in DR16. New single-fiber optical spectroscopy released in DR17 is from the SPectroscipic IDentification of ERosita Survey subsurvey and the eBOSS-RM program. Along with the primary data sets, DR17 includes 25 new or updated value-added catalogs. This paper concludes the release of SDSS-IV survey data. SDSS continues into its fifth phase with observations already underway for the Milky Way Mapper, Local Volume Mapper, and Black Hole Mapper surveys.
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| 8. |
- Yang, Yiping, et al.
(author)
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A contracting Intertropical Convergence Zone during the Early Heinrich Stadial 1
- 2023
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In: Nature Communications. - 2041-1723. ; 14:1
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Journal article (peer-reviewed)abstract
- Despite the fact that the response of tropical hydroclimate to North Atlantic cooling events during the Heinrich Stadial 1 (HS1) has been extensively studied in African, South American and Indonesia, the nature of such responses remains debated. Here we investigate the tropical hydroclimate pattern over the Indo-Asian-Australian monsoon region during the HS1 by integrating hydroclimatic records, and examining a δ18Oseawater record from Globigerinoides ruber (white) in the tropical Indian Ocean. Our findings indicate that tropical hydrological conditions were synchronously arid in both hemispheres during the early HS1 (~18.3-16.3 ka) in the Indo-Asian-Australian monsoon region, except for a narrow, wet hydrological belt in northern low latitudes, suggesting the existence of a contracted tropical precipitation belt at that time. This study reveals that the meltwater discharge and resulting changes in global temperatures and El Niño exerted a profound influence on the tropical hydroclimate in the Indo-Asian-Australian monsoon region during the early HS1.
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