High temperature oxidation behaviors of equimolar NbTiZrV and NbTiZrCr refractory complex concentrated alloys (RCCAs)

Butler, T.M.; Chaput, K.J.; Dietrich, J.R.; Senkov, O.N.

doi:10.1016/j.jallcom.2017.09.164

Cited by 154 publications

(46 citation statements)

References 29 publications

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“…Obviously, decent oxidation resistance requires the addition of significant amounts of Al, Cr and possibly Si to HEAs. So far this has been scarcely done in literature [9][10][11][18][19][20][21][22]. Our own exploratory work indicates the positive effects of Ta-substitution for Nb within the alloy system NbMoCrTiAl.…”

Section: Introductionmentioning

confidence: 81%

On the oxidation mechanism of refractory high entropy alloys

et al. 2019

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The high-temperature oxidation mechanism of a series of refractory high entropy alloys: TaMoCrTiAl, NbMoCrTiAl, NbMoCrAl and TaMoCrAl at 1000°C in air was studied. A complex protective oxide layer consisting of Al2O3, Cr2O3 and CrTaO4 oxides was observed for the quinary Ta-containing alloy. The formation of CrTaO4 in this alloy after a short incubation period decreased the oxidation kinetics from a parabolic to a quartic rate law. Ti was found to support the formation of CrTaO4. In the Nbcontaining alloys, the formation of different Nb2O5 polytypes near the metal/oxide interface caused a highly porous oxide scale and severe oxide spallation.

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Section: Introductionmentioning

confidence: 81%

On the oxidation mechanism of refractory high entropy alloys

et al. 2019

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“…The Nb 2 O 5 oxide can initially form a protective layer but, with the growth of a scale, induces stresses along the oxide-metal interface, resulting in the scale cracking and breakaway oxidation [36,51]. The complex TiNb 2 O 7 oxide, which most likely appeared due to the reaction of Nb with TiO 2 and oxygen or as a consequence of the solid-state reaction between Nb 2 O 5 and TiO 2 oxides [28,52,53], causes a similar effect [52]. Thus, it can be concluded that the formation of the Nb 2 O 5 and TiNb 2 O 7 oxides at 600 °C allows the metal to oxidize according to an undesirable oxygen-alloy interface reaction process [45] due to the continuous cracking/spallation of the oxide scale.…”

Section: Discussionmentioning

confidence: 99%

“…However, refractory elements and their alloys are generally vulnerable to oxidation. A number of studies focused on oxidation behavior of different RHEAs [23,24,25,26,27,28,29,30,31,32,33] have demonstrated that some of them possess much better oxidation resistance than conventional refractory alloys; however, the oxidation behavior strongly depended on the alloy composition and testing conditions. Note that the vast majority of the performed research was conducted at temperatures of T ≥ 1000 °C [23,24,25,26,27,28,33].…”

Section: Introductionmentioning

confidence: 99%

Oxidation Behavior of Refractory AlNbTiVZr0.25 High-Entropy Alloy

et al. 2018

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Oxidation behavior of a refractory AlNbTiVZr0.25 high-entropy alloy at 600–900 °C was investigated. At 600–700 °C, two-stage oxidation kinetics was found: Nearly parabolic oxidation (n = 0.46–0.48) at the first stage, transitioned to breakaway oxidation (n = 0.75–0.72) at the second stage. At 800 °C, the oxidation kinetics was nearly linear (n = 0.92) throughout the entire duration of testing. At 900 °C, the specimen disintegrated after 50 h of testing. The specific mass gains were estimated to be 7.2, 38.1, and 107.5, and 225.5 mg/cm2 at 600, 700, and 800 °C for 100 h, and 900 °C for 50 h, respectively. Phase compositions and morphology of the oxide scales were analyzed using X-ray diffraction (XRD) and scanning electron microscopy (SEM). It was shown that the surface layer at 600 °C consisted of the V2O5, VO2, TiO2, Nb2O5, and TiNb2O7 oxides. Meanwhile, the scale at 900 °C comprised of complex TiNb2O7, AlNbO4, and Nb2Zr6O17 oxides. The oxidation mechanisms operating at different temperatures were discussed and a comparison of oxidation characteristics with the other alloys was conducted.

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“…From an advanced nuclear reactor application point of view, the new generation of HEAs shows superior mechanical properties, exceptional radiation resistance and better oxidation compliance as well as swelling resistance at high temperatures compared to Ni-based superalloys. [53][54][55][56][57][58] While investigating the enormous number of derivative HEAs compositions and their microstructures would be valuable, it also presents big challenges to match the explosion of new alloy bases. New high throughput experiments are needed as well as new fundamental models are important to quickly narrow the path between properties that sensibly depend on both alloy composition and designed microstructures.…”

Section: Introductionmentioning

confidence: 99%