Excellent mechanical properties and thermal stability in a Zr gettering treated (VNb)80(TaTi)20 refractory multi-principal element alloy

Qing Han, Yaguang Dong, Qiuhong Zhang, Xiaoyang Zhou, Cunyong Wang, Shihai Sun, Ke Jin*, Yunfei Xue

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Refractory multi-principal element alloys (RMPEAs) have garnered attention due to their high strength at elevated temperatures. However, their insufficient uniform elongation and thermal stability hinder their practical application. In this work, a single-phase BCC-structured (VNb)80(TaTi)20 RMPEA is designed based on the considerations of mixing enthalpy and Labusch solid solution strengthening model, which exhibits a tensile strength over 900 MPa and uniform elongation of ∼19 %. Unfortunately, the alloys containing high-concentration interstitial impurities (e.g. 300 wppm O, HO-alloy) suffer from severe embrittlement during long-term thermal aging, mainly due to the formation of Ti-(C/N/O) precipitates. By applying the Zr-foil gettering treatment, the concentration of interstitial impurities can be reduced below 100 ppm (LO-alloy), which greatly enhances thermal stability. The LO-alloy can maintain the microstructural stability and mechanical properties under thermal aging at 900 and 1000 °C for at least 1000 h. In addition to the desired combination of strength and ductility at room temperature, the alloy holds a high specific tensile strength of 98.9 MPa cm3/g at 1000 °C, which further grants it strong application potential at elevated temperatures. During tensile deformation, twinning is observed at room temperature, which is believed to enhance both strength and ductility.

Original languageEnglish
Article number148299
JournalMaterials Science and Engineering: A
Volume934
DOIs
Publication statusPublished - Jul 2025

Keywords

  • Interstitial impurities
  • Mechanical properties
  • Phase stability
  • Refractory multi-principal element alloy (RMPEA)

Cite this