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Effect of Aluminium content on oxidation behavior of arc melted AlxCoCrFeNi (x=0,0.3,0.6,1 mole) high entropy alloys exposed at 1150ºC and comparison with nanocrystalline Al0.6CoCrFeNi high entropy alloy

Bhattacharya, Rahul LU ; Murty, B.S. ; Fabijanic, D. ; Annasamy, M. and Hodgson, P. (2018) 25th International Symposium on Metastable, Amorphous and Nanostructured Materials 2018 at the Frentani Convention Centre, in Rome, Italy
Abstract
High entropy alloys (HEA) containing Al and Cr have been observed to manifest
impressive dry air oxidation resistance. But the testing temperature attempted in
the previous works has been restricted up to 1050ºC. In the present work AlxCoCrFeNi HEAs (x=0,0.3,0.6,1 mole) synthesized by arc melting route have been
subjected to rigorous dry air oxidation test up to 1150ºC. The as cast HEAs with
x=0 and x=0.3 show single phase FCC structure whereas those with x=0.6 and
x=1 shows dual phase FCC+BCC structure and dual phase B2+BCC structure
respectively. Increase in Al content increases the Al, Ni rich BCC phase fraction.
Subjected to oxidation at 1150ºC for 24h, CoCrFeNi (x=0) developed a continuous Cr2O3 layer,... (More)
High entropy alloys (HEA) containing Al and Cr have been observed to manifest
impressive dry air oxidation resistance. But the testing temperature attempted in
the previous works has been restricted up to 1050ºC. In the present work AlxCoCrFeNi HEAs (x=0,0.3,0.6,1 mole) synthesized by arc melting route have been
subjected to rigorous dry air oxidation test up to 1150ºC. The as cast HEAs with
x=0 and x=0.3 show single phase FCC structure whereas those with x=0.6 and
x=1 shows dual phase FCC+BCC structure and dual phase B2+BCC structure
respectively. Increase in Al content increases the Al, Ni rich BCC phase fraction.
Subjected to oxidation at 1150ºC for 24h, CoCrFeNi (x=0) developed a continuous Cr2O3 layer, while for Al0.3CoCrFeNi, a Cr2O3 surface layer and internal discontinuous Al2O3 was observed. Under same testing condition Al0.6CoCrFeNi and AlCoCrFeNi HEAs exhibited a single layer of protective, adherent, tenacious and continuous Al2O3. Al0.6CoCrFeNi was also synthesized via mechanical alloying and consolidated by spark plasma sintering to produce nanocrystalline HEA having FCC+BCC structure. When the nanocrystalline Al0.6CoCrFeNi HEA was subjected to similar oxidation parameters it has formed a protective continuous Al2O3oxide layer relatively sooner than microcrystalline Al0.6CoCrFeNi synthesized by arc melting. This can be attributed to the large grain boundary area available in the nanocrystalline HEA which acts as pathways and facilitates easier grain boundary diffusion and hence quicker formation of the protective oxide layer. The oxidation resistance of Al0.6CoCrFeNi and AlCoCrFeNi HEAs exceeds manifold than that of CoCrFeNi and Al0.3CoCrFeNi as well as is far superior to that of Inconel 718 and Inconel 600 superalloys in terms of oxide layer thickness, adherence, stability and protective nature. This is due to their higher Al content which remains dissolved in the multicomponent BCC phase owing to configurational entropy stabilization. The oxidation resistance is also observed to increase with the corresponding increase of the multicomponent BCC phase fraction which acts as the reservoir of Aluminum. (Less)
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; ; ; and
publishing date
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Contribution to conference
publication status
published
subject
keywords
High entropy alloys, oxidation behaviour, Mechanical alloying, Spark plasma sintering, High resolution transmission electron microscopy, Scanning electron microscope (SEM), X ray diffraction, EDS, EBSD, Scanning Transmission Electron Microscopy, GDOES, Powder metallurgy (PM), Physical Metallugy, Thermodynamics and kinetics, Sintering, Microstructural evolution, Mechanical properties, Annealing, Heat treatment, Casting, Furnace control
pages
1 pages
conference name
25th International Symposium on Metastable, Amorphous and Nanostructured Materials 2018 at the Frentani Convention Centre, in Rome, Italy
conference location
Rome, Italy
conference dates
2018-07-02 - 2018-07-06
language
English
LU publication?
no
id
8d1a470e-da7b-4ca2-98f8-91a7b78b6281
date added to LUP
2025-09-23 22:21:14
date last changed
2025-10-09 11:17:02
@misc{8d1a470e-da7b-4ca2-98f8-91a7b78b6281,
  abstract     = {{High entropy alloys (HEA) containing Al and Cr have been observed to manifest<br/>impressive dry air oxidation resistance. But the testing temperature attempted in<br/>the previous works has been restricted up to 1050ºC. In the present work AlxCoCrFeNi HEAs (x=0,0.3,0.6,1 mole) synthesized by arc melting route have been<br/>subjected to rigorous dry air oxidation test up to 1150ºC. The as cast HEAs with<br/>x=0 and x=0.3 show single phase FCC structure whereas those with x=0.6 and<br/>x=1 shows dual phase FCC+BCC structure and dual phase B2+BCC structure<br/>respectively. Increase in Al content increases the Al, Ni rich BCC phase fraction.<br/>Subjected to oxidation at 1150ºC for 24h, CoCrFeNi (x=0) developed a continuous Cr2O3 layer, while for Al0.3CoCrFeNi, a Cr2O3 surface layer and internal discontinuous Al2O3 was observed. Under same testing condition Al0.6CoCrFeNi and AlCoCrFeNi HEAs exhibited a single layer of protective, adherent, tenacious and continuous Al2O3. Al0.6CoCrFeNi was also synthesized via mechanical alloying and consolidated by spark plasma sintering to produce nanocrystalline HEA having FCC+BCC structure. When the nanocrystalline Al0.6CoCrFeNi HEA was subjected to similar oxidation parameters it has formed a protective continuous Al2O3oxide layer relatively sooner than microcrystalline Al0.6CoCrFeNi synthesized by arc melting. This can be attributed to the large grain boundary area available in the nanocrystalline HEA which acts as pathways and facilitates easier grain boundary diffusion and hence quicker formation of the protective oxide layer. The oxidation resistance of Al0.6CoCrFeNi and AlCoCrFeNi HEAs exceeds manifold than that of CoCrFeNi and Al0.3CoCrFeNi as well as is far superior to that of Inconel 718 and Inconel 600 superalloys in terms of oxide layer thickness, adherence, stability and protective nature. This is due to their higher Al content which remains dissolved in the multicomponent BCC phase owing to configurational entropy stabilization. The oxidation resistance is also observed to increase with the corresponding increase of the multicomponent BCC phase fraction which acts as the reservoir of Aluminum.}},
  author       = {{Bhattacharya, Rahul and Murty, B.S. and Fabijanic, D. and Annasamy, M. and Hodgson, P.}},
  keywords     = {{High entropy alloys; oxidation behaviour; Mechanical alloying; Spark plasma sintering; High resolution transmission electron microscopy; Scanning electron microscope (SEM); X ray diffraction; EDS; EBSD; Scanning Transmission Electron Microscopy; GDOES; Powder metallurgy (PM); Physical Metallugy; Thermodynamics and kinetics; Sintering; Microstructural evolution; Mechanical properties; Annealing; Heat treatment; Casting; Furnace control}},
  language     = {{eng}},
  title        = {{Effect of Aluminium content on oxidation behavior of arc melted AlxCoCrFeNi (x=0,0.3,0.6,1 mole) high entropy alloys exposed at 1150ºC and comparison with nanocrystalline Al0.6CoCrFeNi high entropy alloy}},
  year         = {{2018}},
}