Strengthening of nanoprecipitations in an annealed Al0.5CoCrFeNi high entropy alloy

Niu, Sizhe; Kou, Hongchao; Guo, Tong; Zhang, Yu; Wang, Jun; Li, Jinshan

doi:10.1016/j.msea.2016.06.040

Cited by 174 publications

(37 citation statements)

References 29 publications

(33 reference statements)

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“…These two kinds of BCC/B2 microstructures are resulted from the composition segregation, which could be also verified by the XRD results that the diffraction peaks of BCC and B2 phases are widened clearly (Figure 1). Thereof, in the BCC/B2 regions with a very high Al content, the ordered B2 phase becomes the matrix, and the disorder BCC is the precipitated phase with a spherical morphology, which is contrary to the common image that the ordered phase is always precipitated on the disordered BCC matrix [30][31][32][33][34][35][36].…”

Section: Microscopic Morphologies Of Bcc/b2 Phases In Heasmentioning

confidence: 90%

“…More importantly, the unique morphology of the cuboidal B2 phase coherently-embedded into the disordered BCC matrix renders this HEA with both a higher tensile strength (σ UTS = 1223 MPa) and a good ductility of 8% at room temperature. Although the BCC/B2 morphologies were reported in some HEAs sporadically [20,23,30], the elaborate morphology variations of the disordered BCC and its ordered B2 phases have not been studied systematically by far since BCC and B2 phases are always coherent, which is of crucial importance for improving the mechanical property.…”

Section: Introductionmentioning

confidence: 99%

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The BCC/B2 Morphologies in AlxNiCoFeCr High-Entropy Alloys

Jiang

et al. 2017

Metals

130

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Abstract:The present work primarily investigates the morphological evolution of the body-centered-cubic (BCC)/B2 phases in Al x NiCoFeCr high-entropy alloys (HEAs) with increasing Al content. It is found that the BCC/B2 coherent morphology is closely related to the lattice misfit between these two phases, which is sensitive to Al. There are two types of microscopic BCC/B2 morphologies in this HEA series: one is the weave-like morphology induced by the spinodal decomposition, and the other is the microstructure of a spherical disordered BCC precipitation on the ordered B2 matrix that appears in HEAs with a much higher Al content. The mechanical properties, including the compressive yielding strength and microhardness of the Al x NiCoFeCr HEAs, are also discussed in light of the concept of the valence electron concentration (VEC).

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Section: Microscopic Morphologies Of Bcc/b2 Phases In Heasmentioning

confidence: 90%

Section: Introductionmentioning

confidence: 99%

The BCC/B2 Morphologies in AlxNiCoFeCr High-Entropy Alloys

Jiang

et al. 2017

Metals

130

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“…More importantly, the unique morphology of the cuboidal B2 phase coherentlyembedded into the disordered BCC matrix renders this HEA with both a higher tensile strength (σUTS = 1223 MPa) and a good ductility of 8 % at room temperature. Although the evolutions of phase structures and mechanical properties with the Al content in the AlxCoCrFeNi HEA series have been widely investigated [19][20][21][22]29], the microscopic morphologies of the disordered BCC and its ordered B2 phases have not been studied systematically by far since BCC and B2 phases are always coherent, which is of crucial importance for improving the mechanical property.…”

Section: Introductionmentioning

confidence: 99%

The BCC/B2 Morphologies in AlxNiCoFeCr High-Entropy Alloys

Ma¹,

Jiang²,

Li³

et al. 2017

Preprint

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Abstract:The present work investigates primarily the morphology evolution of the body-centeredcubic (BCC)/B2 phases in AlxNiCoFeCr high-entropy alloys (HEAs) with increasing Al content, which has been neglected so far. There exist two types of microscopic morphologies of BCC and B2 phases in this HEA series: one is the weave-like morphology induced by the spinodal decomposition, and the other is the microstructure of a spherical disordered BCC precipitation on the ordered B2 matrix that appears in HEAs with a much higher Al content. The shape of coherent precipitates is found to be closely related to the lattice misfit between BCC and B2 phases, which is sensitive to Al. The mechanical properties, including the compressive yielding strength and microhardness of the AlxNiCoFeCr HEAs, are also discussed in light of the concept of the valence electron concentration (VEC).

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“…[164] The Al 0.5 CrFeCoNi HEA demonstrated an increase in yield strength and ultimate strength with the aging treatment at 650 C for 30 min to 8 h, but with the reduction in ductility. [165] The yield strength of %714 MPa and ultimate strength of %355 MPa in as-cast condition increased to 1220 and 834 MPa, respectively, after aging treatment for 8 h. The formation of www.advancedsciencenews.com www.aem-journal.com nano-sized precipitates (%18 nm) in FCC phase and B2 precipitates (%70 nm) in BCC phase is attributed to the increase in strength and the reduction in ductility. The annealing of as-cast Al 0.3 CrFeCoNi HEA has a significant effect on the mechanical properties due to the formation of L1 2 fine precipitates at 700 C and B2 coarse precipitates at 900 C. [152] The yield strength increases from %175 MPa in the as-cast condition to %300 and %250 MPa after annealing at 700 and 900 C, respectively, and significant work hardening is observed for the alloy annealed at 900 C. The presence of fine nano L1 2 precipitates and coarse B2 precipitates are attributed to the high yield stress at 700 C and large work hardening at 900 C, respectively.…”

Section: Age Hardening Behaviormentioning

confidence: 95%

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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Strengthening of nanoprecipitations in an annealed Al0.5CoCrFeNi high entropy alloy

Cited by 174 publications

References 29 publications

The BCC/B2 Morphologies in AlxNiCoFeCr High-Entropy Alloys

The BCC/B2 Morphologies in AlxNiCoFeCr High-Entropy Alloys

The BCC/B2 Morphologies in AlxNiCoFeCr High-Entropy Alloys

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

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