Characterization of Fe–C–N alloys’ mechanical properties

Melting a Fe–0.9wt.%C alloy under elevated nitrogen pressures produced carbide- and nitride-free alloys. The combination of high interstitial concentrations, approaching 2 wt.%, and duplex bcc-Fe/fcc-Fe microstructure resulted in alloys with compression yield strength in excess of 3 GPa while retaining over 20% ductility and with wear properties comparable to white cast irons. Statistical analysis showed a strong correlation between microstructure/nitrogen concentration and mechanical properties: hardness, strength, and wear. By the combination of both carbon and nitrogen, this process for the first time extended the interstitial concentration in iron to 2 wt.%.