Alloying behaviour, thermal stability and phase evolution in quinary AlCoCrFeNi high entropy alloy

Shivam, Vikas; Basu, Joysurya; Pandey, Vivek Kumar; Shadangi, Yagnesh; Mukhopadhyay, N. K.

doi:10.1016/j.apt.2018.06.006

Cited by 147 publications

(39 citation statements)

References 33 publications

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“…This new phase was identified to be the L1 2 phase by QualX 2.0 [ 34 ], similar XRD peak of carbides with L1 2 phase in AlCoCrFeNi was reported in Ref. [ 35 ]. Intensity of these new peaks became stronger when the temperature increased to above 1000 °C, indicating higher concentration of L1 2 phase with increasing temperature.…”

Section: Resultssupporting

confidence: 69%

Carbide Formation in Refractory Mo15Nb20Re15Ta30W20 Alloy under a Combined High-Pressure and High-Temperature Condition

Zhang

Bhandari

Zeng

et al. 2020

Entropy

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In this work, the formation of carbide with the concertation of carbon at 0.1 at.% in refractory high-entropy alloy (RHEA) Mo15Nb20Re15Ta30W20 was studied under both ambient and high-pressure high-temperature conditions. The x-ray diffraction of dilute carbon (C)-doped RHEA under ambient pressure showed that the phases and lattice constant of RHEA were not influenced by the addition of 0.1 at.% C. In contrast, C-doped RHEA showed unexpected phase formation and transformation under combined high-pressure and high-temperature conditions by resistively employing the heated diamond anvil cell (DAC) technique. The new FCC_L12 phase appeared at 6 GPa and 809 °C and preserved the ambient temperature and pressure. High-pressure and high-temperature promoted the formation of carbides Ta3C and Nb3C, which are stable and may further improve the mechanical performance of the dilute C-doped alloy Mo15Nb20Re15Ta30W20.

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Section: Resultssupporting

confidence: 69%

Carbide Formation in Refractory Mo15Nb20Re15Ta30W20 Alloy under a Combined High-Pressure and High-Temperature Condition

Zhang

Bhandari

Zeng

et al. 2020

Entropy

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“…It was reported in the literature [10,21,22,31] that the nucleation pathway of Cr containing sigma phase prototype of Cr-Co and Cr-Fe alloys formed either through the BCC/B2 phase or directly from the FCC matrix. BCC/B2 phase prototypes can be transformed to sigma phase due to the high affinity of Cr toward Co, Cr, or Fe.…”

Section: Discussionmentioning

confidence: 99%

Transformations in CrFeCoNiCu High Entropy Alloy Thin Films during In-Situ Annealing in TEM

2020

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In-situ TEM-heating study of the microstructural evolution of CrFeCoNiCu high entropy alloy (HEA) thin films was carried out and morphological and phase changes were recorded. Post annealing investigation of the samples was carried out by high resolution electron microscopy and EDS measurements. The film is structurally and morphologically stable single phase FCC HEA up to 400 °C. At 450 °C the formation of a BCC phase was observed, however, the morphology of the film remained unchanged. This type of transformation is attributed to diffusionless processes (martensitic or massive). From 550 °C fast morphological and structural changes occur, controlled by volume diffusion processes. Fast growing of a new intermetallic phase is observed which contains mainly Cr and has large unit cell due to chemical ordering of components in <100> direction. The surface of the films gets covered with a CrO-type layer, possibly contributing to corrosion resistance of these.

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“…Zhang et al [ 26 ] find the FCC, BCC and B2 in the AlCoCrFeNi sample sinter by spark plasma. Shivam et al [ 28 ] report a similar pattern for the ball milled powders. They find a solid solution phase is formed after 20 h milling, and with further milling, a more homogenized solid solution with finer grains can be achieved.…”

Section: Resultsmentioning

confidence: 62%

“…The image shows the HEA particles had a predominantly irregular shape the heavy fracture observed in the particles. During the ball milling process, continuous fracturing, deformation as well as cold welding increases the diffusivity of the starting elements and lead to the formation of the HEA [ 28 ]. The XRD pattern of the ball milled powders, shock consolidated sample and shock consolidation with heat treatment are shown in the Figure 3 .…”

Section: Resultsmentioning

confidence: 99%

“…The microstructure of Al x CoCrFeNi can be tailored from single FCC solid solution, duplex FCC plus BCC solid solutions to single BCC solid solution by increasing the aluminum mole ratio, meanwhile the hardness increases from 116 HV to 509 HV. Al x CoCrFeNi is fabricated by different methods such as arc melting, microwave sintering [ 3 , 26 , 27 , 28 ].…”

Section: Introductionmentioning

confidence: 99%

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Fabrication of Nanocrystalline AlCoCrFeNi High Entropy Alloy through Shock Consolidation and Mechanical Alloying

Arab

Guo

Zhou

et al. 2019

Entropy

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High entropy alloys (HEAs) are usually fabricated using arc melting which has the disadvantages of diseconomy, and the limitations in the shape and size of final products. However, recently, quite a large amount of research has been carried out to find the fabrication techniques for HEAs with better properties such as mechanical alloying and rapid solidification. In this paper, an AlCoCrFeNi high entropy alloy was successfully fabricated by the shock consolidation technique. In this method, the starting powders were mixed by mechanical alloying and then the shock wave was imposed to the compacted powders by explosion. High levels of residual stress existed in samples fabricated by the shock consolidation method. Due to this, after fabrication of the sample, heat treatment was used to eliminate the residual stress and improve the mechanical properties. The microstructure of the samples before and after heat treatment were examined by XRD, SEM and electron backscatter diffraction (EBSD). The shock consolidated sample and sample with heat treatment both showed the nano-structure. After heat treatment the hardness of the sample was decreased from 715 HV to the 624 HV, however the failure strength increased, and as expected the ductility of the sample was improved after heat treatment.

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Alloying behaviour, thermal stability and phase evolution in quinary AlCoCrFeNi high entropy alloy

Cited by 147 publications

References 33 publications

Carbide Formation in Refractory Mo15Nb20Re15Ta30W20 Alloy under a Combined High-Pressure and High-Temperature Condition

Carbide Formation in Refractory Mo15Nb20Re15Ta30W20 Alloy under a Combined High-Pressure and High-Temperature Condition

Transformations in CrFeCoNiCu High Entropy Alloy Thin Films during In-Situ Annealing in TEM

Fabrication of Nanocrystalline AlCoCrFeNi High Entropy Alloy through Shock Consolidation and Mechanical Alloying

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