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Effect of aluminium content and grain size on oxidation behavior of AlxCoCrFeNi (x=0, 0.3, 0.6, 1 mole) high entropy alloy

Bhattacharya, Rahul LU (2016) First International Conference on High-Entropy Materials at National Tsing Hua University, Hsinchu, Taiwan
Abstract
One of the most anticipated properties of high entropy alloys (HEA) is excellent oxidation resistance. AlxCoCrFeNi (x=0,0.3,0.6,1 mole) HEAs were synthesized by mechanical alloying (MA) followed by consolidation through spark plasma sintering (SPS). Alloys with x = 0 and 0.3 show single phase FCC structure, whereas those with x = 0.6 and 1 have dual phases – FCC and BCC. Interestingly, synthesis through MA-SPS route renders these alloys nanocrystalline and thus creates enormous grain boundary area. Subjected to oxidation in air at 1000°C and 1150°C for 24 hours, CoCrFeNi (x = 0) developed a continuous Cr2O3 layer, while for Al0.3CoCrFeNi, aCr2O3 surface layer and internal Al2O3 was observed. Under the same test conditions, Al0.6CoCrFeNi... (More)
One of the most anticipated properties of high entropy alloys (HEA) is excellent oxidation resistance. AlxCoCrFeNi (x=0,0.3,0.6,1 mole) HEAs were synthesized by mechanical alloying (MA) followed by consolidation through spark plasma sintering (SPS). Alloys with x = 0 and 0.3 show single phase FCC structure, whereas those with x = 0.6 and 1 have dual phases – FCC and BCC. Interestingly, synthesis through MA-SPS route renders these alloys nanocrystalline and thus creates enormous grain boundary area. Subjected to oxidation in air at 1000°C and 1150°C for 24 hours, CoCrFeNi (x = 0) developed a continuous Cr2O3 layer, while for Al0.3CoCrFeNi, aCr2O3 surface layer and internal Al2O3 was observed. Under the same test conditions, Al0.6CoCrFeNi and AlCoCrFeNi exhibited a continuous protective Al2O3 surface layer. The oxidation resistance of Al0.6CoCrFeNi and AlCoCrFeNi synthesized by MA-SPS exceeds that of the same compositions synthesized via arc melting, as well as is far superior to that of Inconel 718 and Inconel 600 superalloys, in terms of oxide layer thickness, adherence and stability. This is due to their higher Al content, which remains dissolved in the alloy phases, owing to configurational entropy stabilization. The substantially large grain boundary area (vis-à-vis arc melted alloys) provides easy diffusion pathways to Al and Cr towards the surface, resulting in the formation of a tenacious Al2O3 layer. (Less)
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published
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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, CALPHAD
conference name
First International Conference on High-Entropy Materials at National Tsing Hua University, Hsinchu, Taiwan
conference location
Hsinchu, Taiwan
conference dates
2016-11-06 - 2016-11-09
language
English
LU publication?
no
id
d51045e0-f33f-4c22-88f3-8138bd878258
date added to LUP
2025-09-23 20:28:47
date last changed
2025-10-07 13:25:17
@misc{d51045e0-f33f-4c22-88f3-8138bd878258,
  abstract     = {{One of the most anticipated properties of high entropy alloys (HEA) is excellent oxidation resistance. AlxCoCrFeNi (x=0,0.3,0.6,1 mole) HEAs were synthesized by mechanical alloying (MA) followed by consolidation through spark plasma sintering (SPS). Alloys with x = 0 and 0.3 show single phase FCC structure, whereas those with x = 0.6 and 1 have dual phases – FCC and BCC. Interestingly, synthesis through MA-SPS route renders these alloys nanocrystalline and thus creates enormous grain boundary area. Subjected to oxidation in air at 1000°C and 1150°C for 24 hours, CoCrFeNi (x = 0) developed a continuous Cr2O3 layer, while for Al0.3CoCrFeNi, aCr2O3 surface layer and internal Al2O3 was observed. Under the same test conditions, Al0.6CoCrFeNi and AlCoCrFeNi exhibited a continuous protective Al2O3 surface layer. The oxidation resistance of Al0.6CoCrFeNi and AlCoCrFeNi synthesized by MA-SPS exceeds that of the same compositions synthesized via arc melting, as well as is far superior to that of Inconel 718 and Inconel 600 superalloys, in terms of oxide layer thickness, adherence and stability. This is due to their higher Al content, which remains dissolved in the alloy phases, owing to configurational entropy stabilization. The substantially large grain boundary area (vis-à-vis arc melted alloys) provides easy diffusion pathways to Al and Cr towards the surface, resulting in the formation of a tenacious Al2O3 layer.}},
  author       = {{Bhattacharya, Rahul}},
  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; CALPHAD}},
  language     = {{eng}},
  title        = {{Effect of aluminium content and grain size on oxidation behavior of AlxCoCrFeNi (x=0, 0.3, 0.6, 1 mole) high entropy alloy}},
  year         = {{2016}},
}