Substitution effects on the crystal structure and nano-micro hardness of the Mo2NiB2-Ni cermets

S. Maruyama, S. Ichijo, Y. Harada, E. Takahashi, T. Hirano, R. Maki

Mo 2 NiB 2 –Ni cermets have been studied by substituting transition metals at the Mo 2 NiB 2 phase metal site to enhance their mechanical properties. Substituting Cr and V changes the crystal structure of Mo 2 NiB 2 from orthorhombic to tetragonal, resulting in improved mechanical properties. However, the correlation between crystal structure alteration and mechanical property enhancement remains unclear. In this study, we investigated the nano–submicron hardness of Cr- and V-substituted Mo 2 NiB 2 –Ni cermets using nano-indentation and first-principles calculations to assess the chemical bonding in the Mo 2 NiB 2 phase. Mo 2 NiB 2 -Ni cermets with a excess Ni binder phase was synthesized, which contains orthorhombic, tetragonal, and Ni phases. Nano-indentation results reveal significantly higher hardness in the tetragonal Mo 2 NiB 2 phase, consistent with crystal orbital Hamilton population (COHP) analysis and integrated crystal orbital Hamilton population (ICOHP) values.

WORLD PM2024 Proceedings

J. Jpn. Soc. Powder Powder Metallurgy

72

S1707

S1711

doi.org/10.2497/jjspm.17F-T15-10