Effect of molybdenum addition on structure and properties of high carbon Fe3Al based intermetallic alloy

The effect of molybdenum addition on structure and properties of high (0.3 wt.%) carbon Fe3Al based intermetallic alloy containing about 16 wt.% alumi nium has been studied. Three different alloys with the following compositio ns Fe-16.3 wt.% Al-0.27 wt.% C, Fe-16 wt.% Al-2.85 wt.%, Mo-0.3 wt.% C and Fe-15.8 wt.% Al-7.5 wt.% Mo-0.3 wt.% C were prepared by a combination of ai r induction melting with flux cover (AIM) and electroslag remelting (ESR). The alloys were characterized with respect to microstructure. Micro-analysi s was carried out by electron probe microanalyser. A considerable amount of solid solubility for molybdenum was observed in the carbon containing Fe3A l alloy. At low (2.85 wt.%) concentration of Mo, Fe3AlC0.5 precipitates wit h dissolved Mo and a small fraction of fine Mo2C precipitates was observed. At a high (7.5 wt.%) concentration of Mo, Fe3AlC0.5 precipitates were tota lly absent and only Mo,C precipitates were observed. Significant improvemen ts in strength on the addition of Mo has been achieved. This may be attribu ted to both solid solution strengthening and precipitation hardening. (C) 2 001 Elsevier Science B.V. All rights reserved.