Hardness of (Hf,Ti,W,Zr)B2/(Hf,Ti,W,Zr)C-based ceramics with varying WB content

Compositionally complex (Hf,Ti,Zr,W)B2/(Hf,Ti,Zr,W)C-based ceramics were produced with different boride and carbide phase contents by varying the C/B4C molar ratio used in boro/carbothermal reduction. A monoboride phase based on WB was detected in all compositions. As the C/B4C ratio was varied, the WB content decreased from 23.7 vol% for a C/B4C ratio of 6.0–15.3 vol% for a C/B4C ratio of 10.3. Further increases in the C/B4C ratio increased the WB content. The monoboride phase contained mainly W and Ti in a solid solution with the nominal composition of (W0.86Ti0.14)B that change with variation in processing conditions. The highest hardness was 27.8 GPa for a ceramic containing 15.3 vol% WB. The Vickers hardness decreased as the content of the softer WB phase increased, indicating the hardness was governed by its content.

Duke Scholars

Author Stefano Curtarolo Thomas Lord Department of Mechanical Engineering and Materia ...