2022IRG1-7

2022 IRG-1 Publication: Stabilization of a Dissimilar Rare-Earth Boride in High-Entropy (Ti_0.2Zr_0.2Hf_0.2Ta_0.2Er_0.2)B₂ with Enhanced Hardness and Grain Boundary Segregation

• In IRG-1, we showed that high-entropy ceramics can have significant solubilities of dissimilar components that can subsequently enable new, tunable, and improved properties.
• 20% ErB₂ can be stabilized in a high-entropy transition metal diboride, despite the dissimilar chemical properties of rare earth and transition metal elements and large differences in their atom/cation radii.
• Single-phase (Ti_0.2Zr_0.2Hf_0.2Ta_0.2Er_0.2)B₂ achieved via boron-metal reactive spark plasma sintering (SPS)
• Phase formation in (Ti_0.2Zr_0.2Hf_0.2Ta_0.2Er_0.2)B₂ depends on the fabrication route.
• The rare earth addition enhances the hardness of (Ti_0.2Zr_0.2Hf_0.2Ta_0.2Er_0.2)B₂.
• Larger Er atoms segregate at grain boundaries, which can influence microstructural evolution.

Jian Luo and co-workers (University of California, San Diego)
Timothy J. Rupert and co-workers (University of California, Irvine)

M Qin, S Shivakumar T Lei, J Gild, EC Hessong, H Wang, KS Vecchio, TJ Rupert, J Luo Journal of European Ceramic Society 2022. https://doi.org/10.1016/j.jeurceramsoc.2022.05.034