An oxidation resistant refractory high entropy alloy protected by CrTaO 4 -based oxide

Kai Chi Lo, Yao Jen Chang, Hideyuki Murakami, Jien Wei Yeh, An Chou Yeh

Research output: Contribution to journalArticle

Abstract

Although refractory high entropy alloys (RHEAs) have shown potentials to be developed as structural materials for elevated temperature applications, most of the reported oxidation behaviours of RHEA were associated with short term exposures for only up to 48 hours, and there is a lack of understanding on the oxidation mechanism of any RHEA to-date. In this work, by using thermogravimetric analysis, isothermal oxidation was conducted on a novel RHEA at 1000 °C and 1100 °C for up to 200 hours, which is an unprecedented testing duration. The external oxide layer strongly influenced the weight gain behaviours, and it consisted of CrTaO 4 -based oxide with some dispersion of Al 2 O 3 and Cr 2 O 3 . At 1000 °C, the inability to form dense CrTaO 4 -based oxide layer resulted an exponential dependence of weight gain throughout 200 hours. At 1100 °C, mass gain curve showed two parabolic dependences associated with the formation of protective CrTaO 4 -based oxide layer and the weight gain after 200 hours was 4.03 mg/cm 2 , which indicates that it is one of the most oxidation resistant RHEAs comparing to literature data to-date. This work can also provide insights on how to further develop RHEA to withstand long term oxidation at elevated temperatures.

Original languageEnglish
Article number7266
JournalScientific reports
Volume9
Issue number1
DOIs
Publication statusPublished - 2019 Dec 1

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refractories
entropy
oxidation
oxides
temperature
curves

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An oxidation resistant refractory high entropy alloy protected by CrTaO 4 -based oxide . / Lo, Kai Chi; Chang, Yao Jen; Murakami, Hideyuki; Yeh, Jien Wei; Yeh, An Chou.

In: Scientific reports, Vol. 9, No. 1, 7266, 01.12.2019.

Research output: Contribution to journalArticle

Lo, Kai Chi ; Chang, Yao Jen ; Murakami, Hideyuki ; Yeh, Jien Wei ; Yeh, An Chou. / An oxidation resistant refractory high entropy alloy protected by CrTaO 4 -based oxide In: Scientific reports. 2019 ; Vol. 9, No. 1.
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