Fig. 1. SEM micrographs of (a) NFA and (b) 25 vol.% Cr3C2@SiC-NFA composite after the SPS sintering (the right side is the magnified image of the left side for each sample).

Fig. 2. (a) IPF map of the NFA sample; IPF maps of (b) α-ferrite grains and (c) M7C3 grains, and (d) phase map of the 25 vol.% Cr3C2@NFA-SiC composite after the SPS sintering.

Fig. 3. SEM micrographs of (a) NFA and (b) 25 vol% Cr3C2@SiC-NFA composite after the thermal treatment at 1000 °C for 50 h (the right part is the magnified image of the left part).

Fig. 4. (a) Size and (b) volume fraction of P1 and P2 precipitates before and after the 1000 °C thermal treatment for 50 h.

Fig. 5. STEM-BF images (a, c) with corresponding EDS mappings (b, d) for the Cr3C2@SiC-NFA composite after the 1000 °C treatment for 50 h.

Fig. 6. Diffraction patterns from the (a) bright area and (b) dark area (P1) in Fig. 5(a).

Fig. 7. Dissolution kinetics of SiC in the NFA matrix at a sintering temperature of 950 °C.

Fig. 8. Diffusion behaviors of (a) Cr, (b) Si, (c) Fe, and (d) C based on the ThermoCalc-DICTRA simulations during sintering at 950 °C.

Fig. 9. Phase diagram of the Cr3C2@SiC-NFA system.

Fig. 10. TTT diagram of graphite, (Fe,Cr)7C3, and (Ti,W)C phases for the 25 vol.% Cr3C2@SiC-NFA composite.

Fig. 11. ThermoCalc PRISMA simulations of the size of (a) (Fe,Cr)7C3 and (b) (Ti,W)C precipitates and the corresponding experimental values after the sintering and thermal treatment (Data points with error bars show experimental values, which are also reported in Fig. 4(a); curve plots show simulation results).

Fig. 12. SEM micrographs of Cr3C2@SiC-NFA composites after thermal treatment at 1000 °C for (a) 25 h and (b) 75 h.

Fig. 13. ThermoCalc DICTRA simulations of the coarsening rate coefficient of the (Fe,Cr)7C3 and (Ti,W)C precipitates.