jz8b01262_si_liveslides.zip (8.27 MB)
New Tungsten Borides, Their Stability and Outstanding Mechanical Properties
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posted on 2018-06-22, 16:33 authored by Alexander
G. Kvashnin, Hayk A. Zakaryan, Changming Zhao, Yifeng Duan, Yulia A. Kvashnina, Congwei Xie, Huafeng Dong, Artem R. OganovWe
predict new tungsten borides, some of which are promising hard
materials that are expected to be stable in a wide range of conditions,
according to the computed composition–temperature phase diagram.
New boron-rich compound WB5 is predicted to be superhard,
with a Vickers hardness of 45 GPa, to possess high fracture toughness
of ∼4 MPa·m0.5, and to be thermodynamically
stable in a wide range of temperatures at ambient pressure. Temperature
dependences of the mechanical properties of the boron-richest WB3 and WB5 phases were studied using quasiharmonic
and anharmonic approximations. Our results suggest that WB5 remains a high-performance material even at very high temperatures.