Diversified Mechanisms to Ameliorate the Oxidation Behavior of Tizrv0.5nb0.5 Refractory High Entropy Alloy Via Al/Si-Alloying at 1000 ℃

Abstract

For the TiZrV0.5Nb0.5 RHEA as a model material, different mechanisms of Al and Si inhibiting its inherent catastrophic oxidation were systematically elucidated by analyzing the cross-section oxide layer and performing the XPS line scanning technology. Al/Si-alloying enhances oxidation resistance via improving the anti-spallation of oxide layer. A dense niobium oxide protective layer occurred on Si-containing alloy, accompanied by a pinning-effect of second-phase oxides and inhibition of oxide volatilization. Excellent oxidation resistance of TiZrV0.5Nb0.5Al0.75 arises from a significant reduction in the oxygen inward diffusion and subsequent inhibition of oxide volatilization caused by the rapid diffusion and preferential oxidation of Al.

Keywords: Refractory high entropy alloys, oxidation resistance, XPS line scanning, Anti-spallation