Phase Evolution and Densification Behavior of Nanocrystalline Multicomponent High Entropy Alloys During Spark Plasma Sintering

Single-phase, face-centered cubic (FCC) high-entropy alloys (HEA) are promising materials for future applications. In order to improve the mechanical properties, especially the tensile strength of these materials, this study focuses on the combination of spark plasma sintering (SPS) and equal-channel angular pressing (ECAP). The initial fine-grained microstructure produced by SPS is further refined by ECAP in a 90°-die. Optical microscopy and electron backscatter diffraction (EBSD) confirm this considerable grain refinement, leads to a grain size below 1 µm after 1 ECAP pass. An alternating arrangement of fine-grained areas and much coarser regions, aligned under an angle of approximately 27°, is found. Moreover, a first microstructural investigation of the twin structure is conducted. The mechanical behavior was investigated by hardness measurements and tensile testing. Both the hardness and tensile strength are remarkably increased after ECAP. In contrast, the uniform elongation and elongation at fracture are significantly reduced due to the strengthening mechanisms of strain hardening and grain refinement. It is concluded that the combination of SPS and ECAP is an attractive approach for designing (ultra)fine-grained HEAs with superior properties. The investigated techniques could be applied to understand the underlying microstructural mechanisms.

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Microstructures and mechanical properties of FeCoCrNi-Mo High entropy alloys prepared by spark plasma sintering and vacuum hot-pressed sintering

Materials Today Communications ◽

10.1016/j.mtcomm.2020.101009 ◽

2020 ◽

Vol 24 ◽

pp. 101009 ◽

Cited By ~ 2

Author(s):

Y.B. Peng ◽

W. Zhang ◽

X.L. Mei ◽

H.J. Wang ◽

M.Y. Zhang ◽

...

Keyword(s):

Mechanical Properties ◽

Spark Plasma Sintering ◽

High Entropy Alloys ◽

High Entropy ◽

Plasma Sintering ◽

Spark Plasma ◽

Microstructures And Mechanical Properties

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Microstructure and Properties of TiB2/AlFeNiCoCr Composites by Spark Plasma Sintering

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.842.83 ◽

2020 ◽

Vol 842 ◽

pp. 83-89

Author(s):

Dai Hong Xiao ◽

Min Dong Wu

Keyword(s):

Spark Plasma Sintering ◽

Phase Evolution ◽

High Entropy Alloy ◽

Matrix Composites ◽

X Ray Diffraction ◽

Alloy Matrix ◽

High Entropy ◽

Plasma Sintering ◽

Spark Plasma ◽

Temperature And Pressure

TiB2/AlFeNiCoCr high-entropy-alloy-matrix composites were fabricated by spark plasma sintering. Effects of SPS process on microstructure and mechanical properties of 0.5 vol.% TiB2/AlFeNiCoCr composites were studied using X-ray diffraction, density testing, scanning electron microscopy, mechanical property testing. It is shown that increasing of sintering temperature and pressure can improve the relative density and compressive properties of 5 vol. %TiB2/AlCoCrFeNi composites. During the spark plasma sintering, there is phase evolution in the composites. The 5 vol. % TiB2/AlCoCrFeNi composite after sintering at 1200 °C and 30 ~ 45 MPa is composed of phases BCC, B2, FCC, σ and TiB2.

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Synthesis of CuCrFeNiTiAlx high entropy alloys by means of mechanical alloying and spark plasma sintering

Canadian Metallurgical Quarterly ◽

10.1080/00084433.2021.1969497 ◽

2021 ◽

pp. 1-9

Author(s):

Gabriela E. Ruiz-Jasso ◽

Sebastián Díaz-de la Torre ◽

Ricardo Escalona-González ◽

J. Claudio Méndez-García ◽

José A. Castillo Robles ◽

...

Keyword(s):

Mechanical Alloying ◽

Spark Plasma Sintering ◽

High Entropy Alloys ◽

High Entropy ◽

Plasma Sintering ◽

Spark Plasma

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Characterization of Powder Metallurgy High-Entropy Alloys Prepared by Spark Plasma Sintering

Materials Science Forum ◽

10.4028/www.scientific.net/msf.941.1053 ◽

2018 ◽

Vol 941 ◽

pp. 1053-1058 ◽

Cited By ~ 1

Author(s):

Larissa Gouvea ◽

Igor Moravcik ◽

Jan Cizek ◽

Petra Krajnakova ◽

Vít Jan ◽

...

Keyword(s):

Spark Plasma Sintering ◽

High Entropy Alloys ◽

X Ray Diffraction ◽

High Entropy ◽

Average Hardness ◽

Plasma Sintering ◽

Spark Plasma ◽

Multi Phase ◽

Sintering Processes

In the present work, the High-Entropy Alloys Al0.2Co1.5CrFeNi1.5Ti, Al1.3Co1.4Cr2.0FeNi4.0Ti4.0 and Al6.0Co1.2Cr2.5FeNi3.5Ti6.0 were produced by Mechanical Alloying and subsequent Spark Plasma Sintering processes to obtain properly densified bulks. The characterization of the materials was accomplished through X-Ray Diffraction, Scanning Electron Microscopy, microhardness and nanoindentation tests to identify and analyze the acquired microstructures’ features, phases formed, morphology and size of the grains and its average hardness. The results indicate that it was possible to obtain alloys presenting high values of hardness and multi-phase microstructures. The effect of the multiple phases on the microstructures was discussed in terms of its influence on the mechanical properties. A satisfying densification level of the materials was achieved with the selected parameters.

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