Thermal stability and grain boundary strengthening in ultrafine-grained CoCrFeNi high entropy alloy composite

Sathiyamoorthi, Praveen; Basu, Joysurya; Kashyap, Sanjay; Pradeep, Konda Gokuldoss; Kottada, Ravi Sankar

doi:10.1016/j.matdes.2017.08.053

Cited by 216 publications

(44 citation statements)

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“…The overall combined effect should result in a lower rate of grain growth upon heating in HEAs than conventional materials with similar melting points. Such results have been reported in 3d transition and refractory metal HEAs [19,20,21,22], which will be discussed further in the following sections.…”

Section: Coupling Grain-boundary Strengthening With the High-entropy supporting

confidence: 70%

Nanostructured high-entropy materials

2020

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Section: Coupling Grain-boundary Strengthening With the High-entropy supporting

confidence: 70%

Nanostructured high-entropy materials

2020

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“…Meanwhile, the HEAs with these excellent properties drive a new class of materials in nanoscale devices potentially in high-stress and elevated-temperature applications. Sathiyamoorthi et al [96] found that ultrafine-grained CoCrFeNi HEAs show the exceptional thermal stability upon the exposure of sintered compacts to high temperature (973 to 1,173 K) and prolonged duration of 600 h, as illustrated in Fig. 12.…”

Section: Thermal Stabilitymentioning

confidence: 99%

Science and technology in high-entropy alloys

2018

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As human improve their ability to fabricate materials, alloys have evolved from simple to complex compositions, accordingly improving functions and performances, promoting the advancements of human civilization. In recent years, high-entropy alloys (HEAs) have attracted tremendous attention in various fields. With multiple principal components, they inherently possess unique microstructures and many impressive properties, such as high strength and hardness, excellent corrosion resistance, thermal stability, fatigue, fracture, and irradiation resistance, in terms of which they overwhelm the traditional alloys. All these properties have endowed HEAs with many promising potential applications. An in-depth understanding of the essence of HEAs is important to further developing numerous HEAs with better properties and performance in the future. In this paper, we review the recent development of HEAs, and summarize their preparation methods, composition design, phase formation and microstructures, various properties, and modeling and simulation calculations. In addition, the future trends and prospects of HEAs are put forward.

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“…In addition to the alloy matrix, there are two types of impurities, i.e., white particles attached on the surface (Figure 2a) and black spots dispersed in the matrix (Figure 2b). The white particles are presumed to be silica powders in oxide polishing solution (OPS) owing to their similar size (0.04 µm), while the black spots correspond to oxides [17,36]. The impurities are generally introduced by the milling medium and/or the process controlling agent (PCA) during the MA process [37,38].…”

Section: Methodsmentioning

confidence: 99%

“…The white particles are presumed to be silica powders in oxide polishing solution (OPS) owing to their similar size (0.04 μm), while the black spots correspond to oxides [17,35]. The impurities are generally introduced by the milling medium and/or the process controlling agent (PCA) during the MA process [36,37]. As shown in Figure 2b, the HEA consists mainly of a gray phase and a white phase, corresponding to the FCC and BCC phases, respectively, which is in accord with the results reported by Beyramali Kivy et al [8].…”

Section: Methodsmentioning

confidence: 99%

Microstructures and Tribological Properties of TiC Reinforced FeCoNiCuAl High-Entropy Alloy at Normal and Elevated Temperature

Zhu

Zhou

et al. 2020

Metals

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Recent studies have suggested that high-entropy alloys (HEAs) possess high fracture toughness, good wear resistance, and excellent high-temperature mechanical properties. In order to further improve their properties, a batch of TiC-reinforced FeCoNiCuAl HEA composites were fabricated by mechanical alloying and spark plasma sintering. X-ray diffractometry analysis of the TiC-reinforced HEA composites, combined with scanning electron microscopy imaging, indicated that TiC particles were uniformly distributed in the face-centered cubic and body-centered cubic phases. The room temperature hardness of the FeCoNiCuAl HEA was increased from 467 to 768 HV with the addition of TiC, owing to precipitation strengthening and fine grain strengthening effects. As the TiC content increased, the friction coefficient of the FeCoNiCuAl HEA first increased and then decreased at room temperature, due to the transition of the wear mechanism from adhesive to abrasive behavior. At higher temperature, the friction coefficient of the FeCoNiCuAl HEA monotonously reduced, corresponding well with the transition from adhesive wear to oxidative wear.wear resistance of HEAs [8,9]. Recently, it was reported that the addition of Cu can reduce the wear rate of CoCrFeNiCux HEAs at both room temperature and elevated temperatures, and wear resistance at elevated temperatures is promoted more significantly than that at room temperature due to their self-lubricating mechanism [10].However, the major challenge for practical applications of the FeCoNiCuAl HEA is its insufficient strength. Recent studies have indicated that the precipitation of reinforcing phases in various materials, such as HEAs and ceramics, can further increase the yield strength of the alloy while maintaining relatively high ductility [11][12][13]. For instance, the precipitation of SiC nanoparticles in FeCoCrNiMn enhanced the compressive yield strength from 1180 to 1480 MPa at room temperature [14]. The precipitation of WC in the FeCoCrNi HEA leads to an improved hardness up to 768HV, which corresponds well with the transition of the wear mechanism [13]. The alloy may also be strengthened by dispersion strengthening, which can significantly improve the strength and hardness of the alloy, and reduce the plasticity and toughness slightly [15]. TiC is considered a good candidate as the strengthening phase due to its high melting point, high hardness, low density, good metal matrix wettability, good chemical stability, and excellent wear resistance [16]. The optimized yield strength of the (FeCrNiCo)Al 0.75 Cu 0.25 HEA reinforced by TiC particles can reach 1637 MPa, which is increased by 90.6% compared to the (FeCrNiCo)Al 0.75 Cu 0.25 HEA [17]. However, the precipitation of ceramic nanoparticles in the metal matrix tends to be unevenly distributed, which is probably originated from the instability of the interfaces between the ceramic particles and the metal matrix [18][19][20]. In order to make the second phase uniformly distributed in the matrix, in situ methods are widely used to fa...

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Thermal stability and grain boundary strengthening in ultrafine-grained CoCrFeNi high entropy alloy composite

Cited by 216 publications

References 50 publications

Nanostructured high-entropy materials

Nanostructured high-entropy materials

Science and technology in high-entropy alloys

Microstructures and Tribological Properties of TiC Reinforced FeCoNiCuAl High-Entropy Alloy at Normal and Elevated Temperature

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