Oxidation behavior of the Ti38V15Nb23Hf24 refractory high-entropy alloy at elevated temperatures. (15th April 2022)

• Record Type: Journal Article
• Authors: Ouyang, Di; Chen, Zheng-jie; Yu, Hai-bin; Chan, K.C.; Liu, Lin
• Is Part Of: Corrosion science. Volume 198(2022)
• Publication Date: 2022-04-15
• Subjects: Refractory high-entropy alloy -- High-temperature corrosion -- Internal oxidation; Corrosion and anti-corrosives -- Periodicals; 620.11223
• DOI: 10.1016/j.corsci.2022.110153
• Languages: English
• ISSNs: 0010-938X

Abstract

Abstract: The oxidation behavior of the Ti38 V15 Nb23 Hf24 refractory high-entropy alloy (RHEA) in air was systematically studied in this work. Two distinct types of oxidation behavior were observed. Below 1000 ℃, a dense composite oxide scale with highly consistent lattice constant and crystallographic orientation was formed on the surface, while above 1000 ℃, internal oxidation with the formation of needle-like HfO2 occurred in the alloy matrix below the alloy-scale interface. The internal oxidation is caused by the sufficient inward-diffusing oxygen after the decomposition of dense outer oxide layer with sluggish oxygen diffusivity. This research provides new understanding for the development of new antioxidation RHEAs. Graphical Abstract: ga1 Highlights: The dense composite oxide scale formed below 1000 ℃ exhibits highly consistent lattice constant and crystallographic orientation. The dense composite oxide will be decomposed above 1000 ℃ caused by the evaporation of V2 O5 . The growth of needle-like HfO2 in the alloy matrix possesses the preferred direction perpendicular to the ( 1 ¯ 01 ) plane.