The effects of interstitial oxygen on mechanical properties of TiZrNb medium-entropy alloy over a wide temperature range

Abstract

Interstitial oxygen plays an important role in the microstructure and mechanical properties of recently developed refractory high-entropy or complex concentrated alloys. However, the mechanical properties of the oxygen-doped complex concentrated refractory alloy over a wide temperature range remain unclear. In this work, the effect of interstitial oxygen on the mechanical behavior of TiZrNb medium-entropy alloys (MEAs) has been investigated. At room temperature (RT), the interstitial oxygen improves the yield strength and tensile ductility owing to interstitial solid-solution strengthening and strain-hardening enhancement. However, simultaneous improvement of the RT strength-ductility by adding interstitial oxygen comes at the expense of increasing the ductile-brittle transition temperature (DBTT). Furthermore, the high-temperature yield strength of TiZrNb alloy can be improved up to 800 °C with the addition of 2 at% oxygen. The results above provide valuable insight into the mechanical properties of TiZrNb MEA, which would contribute to optimizing the high-performance refractory complex concentrated alloys in various applications.