Collaborative Research: Microscopic Mechanism of Oxide Formation in Multi-Principal Element Alloys

Multi-principal element alloys (MPEAs), such as Al30Cr10(NbTiZr)60, are concentrated solid-solutions typically consisting of 5 or more elements in significant proportions. The superior structural properties (e.g., hardness, strength) of certain MPEAs, unattainable from traditional alloys, has encouraged their potential use for components operating at high temperatures (e.g., gas turbine blades, surface coating for reentry vehicles). Incidentally, degradation by oxidation is a critical materials challenge to overcome for such applications. Consequently, synthesizing oxidation resistant MPEAs is nontrivial because the versatility in elemental compositions for these complex alloys translates to an extensive range of possible oxidation products, many with poor resistance to the penetration of oxygen into the bulk alloy. To address this challenge and explore the associated enormous composition-processing-structure-property landscape, we propose an innovative data-guided adaptive discovery strategy to understand the oxidation mechanism¬––– from atomic scale oxygen chemisorption to microscopic oxide scale formation––– to enable a surface engineering paradigm for the synthesis and processing of MPEAs with improved oxidation resistance.