Metal deficient AlB$_{2}$-type (Ti$_{0.2}$Zr$_{0.2}$Hf$_{0.2}$Nb$_{0.2}$Ta$_{0.2}$)$_{1-\delta}$B$_{2}$ high-entropy diborides with high hardness

Wuzhang Yang; Qinqing Zhu; Guorui Xiao; Zhi Ren

doi:10.1016/j.ceramint.2022.11.100

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arXiv · 2302.07418

Metal deficient AlB$_{2}$-type (Ti$_{0.2}$Zr$_{0.2}$Hf$_{0.2}$Nb$_{0.2}$Ta$_{0.2}$)$_{1-\delta}$B$_{2}$ high-entropy diborides with high hardness

Wuzhang Yang·Qinqing Zhu·Guorui Xiao·Zhi Ren

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Abstract

We report the synthesis and characterization of metal deficient (Ti$_{0.2}$Zr$_{0.2}$Hf$_{0.2}$Nb$_{0.2}$Ta$_{0.2}$)$_{1-\delta}$B$_{2}$ high-entropy diborides (HEBs). A single homogeneous AlB$_{2}$-type phase is successfully obtained over the $\delta$ range of 0.03 $\leq$ $\delta$ $\leq$ 0.18. With increasing $\delta$, the unit-cell volume exhibits a nonmonotonic variation with a maximum at $\delta$ = 0.07. These metal-deficient HEBs possess high Vickers hardness of 16.6-18.9 GPa at a load of 9.8 N and their phase stability is attributed to the increased mixing entropy. Our results not only present the first series of metal-deficient AlB$_{2}$-type HEBs, but also suggest the existence of similar multicomponent diborides.

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Wuzhang Yang, Qinqing Zhu, Guorui Xiao, Zhi Ren. 2023-02-15. Metal deficient AlB$_{2}$-type (Ti$_{0.2}$Zr$_{0.2}$Hf$_{0.2}$Nb$_{0.2}$Ta$_{0.2}$)$_{1-\delta}$B$_{2}$ high-entropy diborides with high hardness. https://doi.org/10.1016/j.ceramint.2022.11.100

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