fig2

Figure 2. Thermodynamic calculations and experimental verifications of Sm₂Co₁₇ alloys with different grain sizes^[74]. (A) Calculated Gibbs free energy differences between hexagonal (2:17H) and rhombohedral (2:17R) phases as a function of grain size at different temperatures. (B) Calculated Gibbs free energies of nanocrystalline 2:17H and 2:17R phases as a function of grain size at 1000 K. (C) Transmission electron microscopy images, electron diffraction patterns and indexing of nanocrystalline Sm₂Co₁₇ bulk samples in the as-prepared state (C1), annealed at 973 K for 1 h (C2) and annealed at 1073 K for 1 h (C3), respectively.