Synergistic dispersion strengthening of Fe-Cr alloys by oxides and carbides: Microstructure and mechanical property enhancement

Fe-Cr alloys were fabricated using powder metallurgy (PM) with varying additions of ZrC (0–1.5 wt%) to investigate the influence on microstructure and mechanical properties. The resulting alloys exhibited a bimodal grain structure with dispersed nano-oxides (TaO, ZrO 2 ) and carbides (ZrC). The alloy containing 1.5 wt% ZrC demonstrated the most favourable combination of properties, achieving a yield strength of 1373 MPa and an elongation of 11.9 % at room temperature, which is attributed to synergistic dispersion strengthening. At 700°C, this alloy retained a yield strength of 470 MPa, surpassing that of many oxide dispersion-strengthened alloys. Incorporating ZrC refined the microstructure, promoted phase transformations, and inhibited the formation of coarse oxides, enhancing strength and ductility.