Table 3 Composition, stoichiometry, density, hardness values, and modulus values for each composition. Theoretical density was calculated using lattice parameters from XRD and atomic ratios from EDS and CHNS chemical analysis, except for HECN#6 which was calculated using the weighted average density of the monocarbide/nitride precursors.
Label | Nominal composition | x (C + N) | Measured density (g/cm3) | Theoretical density (g/cm3) | Relative density (%) | Nanoindentation hardness (GPa) | ROM hardness (GPa) | Nanoindentation modulus (GPa) | ROM modulus (GPa) | Measured VEC | Single phase? |
|---|---|---|---|---|---|---|---|---|---|---|---|
HEN #1 | (HfNbTaTiZr)1Nx | 0.88 | 10.09 | 10.18 | 99.1 | 27.8 | 22.5 | 502.6 | 422.7 | 8.7 | Yes |
HEN #2 | (CrNbTaTiV)1Nx | 0.83 | 8.33 | 8.46 | 98.5 | 24.4 | 21.9 | 476.7 | 405.0 | 9.1 | Yes |
HEN #3 | (CrHfNbTaTi)1Nx | 0.90 | 9.50 | 10.39 | 91.4 | 26.2 | 22.6 | 488.9 | 410.7 | 9.1 | Yes |
HEN #4 | (CrHfNbTiZr)1Nx | 0.91 | 8.15 | 8.61 | 94.7 | 27.3 | 20.9 | 488.4 | 427.4 | 8.8 | Yes |
HEN #5 | (CrHfTaTiZr)1Nx | 0.92 | 9.56 | 10.16 | 94.1 | 26.5 | 21.7 | 465.5 | 423.9 | 8.9 | Yes |
HECN #1 | (HfNbTaTiZr)1(CN)x | 0.91 | 9.54 | 9.68 | 98.5 | 32 | 22.4 | 557.9 | 431.0 | 8.3 | Yes |
HECN #2 | (CrNbTaTiV)1(CN)x | 0.81 | 8.16 | 8.14 | 100 | 30 | 21.9 | 518.2 | 415.0 | 8.6 | Yes |
HECN #3 | (CrHfNbTaTi)1(CN)x | 0.91 | 10.05 | 10.21 | 98.4 | 29.9 | 22.0 | 564.5 | 419.8 | 8.7 | No—some chemical segregation |
HECN #4 | (CrHfNbTiZr) 1(CN)x | 0.90 | 8.35 | 8.43 | 99.0 | 30.4 | 22.5 | 531.9 | 429.2 | 8.4 | Yes |
HECN #5 | (CrHfTaTiZr) 1(CN)x | 0.89 | 9.84 | 9.86 | 99.8 | 29.7 | 22.5 | 550 | 425.8 | 8.3 | Yes |
HECN #6 | (CrMoTaVW) 1(CN)x | 0.65 | 9.13 | 10.11 | 90.3 | – | – | – | – | 8.3 | No—two phases |
