High-Temperature Oxidation Behavior of Refractory High-Entropy Alloys: Effect of Alloy Composition
- 1.2k Downloads
The high-temperature oxidation behavior of a new family of refractory high-entropy alloys (HEAs) with compositions of W–Mo–Cr–Ti–Al, Nb–Mo–Cr–Ti–Al and Ta–Mo–Cr–Ti–Al was studied at 1000 and 1100 °C. Based on these equimolar starting compositions, the main incentive of this study was to select the most promising alloy system whose properties may then be successively improved. Despite the high amount of refractory elements, Ta–Mo–Cr–Ti–Al showed good oxidation resistance at 1000 and 1100 °C. Moderate values of mass gain and complex oxidation kinetics were observed for the W- and Nb-containing HEAs. These alloys formed inhomogeneous oxide scales possessing regions with thick and porous layers as well as areas revealing quite thin oxide scales due to the formation of discontinuous Cr- and Al-rich scales. The most promising behavior was shown by the alloy Ta–Mo–Cr–Ti–Al which followed the parabolic rate law for oxide growth due to the formation of a thin and compact Al-rich layer.
KeywordsHigh-entropy alloys Refractory metals Oxidation kinetics Oxide scale morphology Oxide evaporation
The financial support by Deutsche Forschungsgemeinschaft (DFG) is gratefully acknowledged.
- 2.R. Syre, Niobium, Molybdenum, Tantalum and Tungsten: A Summary of Their Properties with Recommendation for Research and Development (North Atlantic Treaty Organization, Advisory Group For Aeronautical Research and Development, 1961).Google Scholar
- 5.M. Azim, D. Schliephake, C. Hochmuth, B. Gorr, H.-J. Christ, U. Glatzel, and M. Heilmaier, Journal of Minerals 57, 2621 (2015).Google Scholar
- 7.O. N. Senkov, C. Woodward, and D. B. Miracle, Journal of Minerals 66, 2030 (2014).Google Scholar
- 18.N. M. Geyer, Protection of Refractory Metals Against Atmospheric Environments, http://contrails.iit.edu/DigitalCollection/1961/ASDTR61-322article07.pdf. Assessed 1 March 2016.
- 22.W. D. Klopp, Recent Developments in Chromium and Chromium Alloys, NASA-Report TM X-1867 (1969).Google Scholar
- 23.R. P. Elliot, Transaction of the ASM 52, 900 (1960).Google Scholar
- 26.R. L. Wagner, Metallurgical Transactions 1, 3365 (1970).Google Scholar
- 27.A. Taylor, Research for Solubility of Interstitials in Columbium Part III. A Study of Columbium-Rich Alloys in the Ternary Systems Cb-Mo-O, Cb-Mo-N and Cb-Mo-C, Technical Report, Westinghouse Research Labs Pittsburgh (1966).Google Scholar
- 28.F. E. Bacon and P. M. Moanfeldt, Reaction with common gases, Columbium and Tantalum (Wiley, New York, 1963).Google Scholar
- 29.D. E. Weaver, The diffusivity and Solubility of Nitrogen in Molybdenum and Trapping of Nitrogen by Carbon in Molybdenum, PhD Thesis, Lawrence Livermore Laboratory, University of California (1972).Google Scholar