Effect of Titanium and Carbon on Microstructure and Mechanical Properties of Disordered Solid Solution Fe-7 wt%Al Alloy

The effect of combined addition of carbon and titanium on structure and properties of Fe-7 wt%Al alloys has been studied. Pancakes of four alloys with nominal compositions, Fe-7Al-0.05C-0.2Ti (alloy-1), Fe-7Al-0.5C-2.0Ti (alloy-2), Fe-7Al-1.0C-4.0Ti (alloy-3) and Fe-7Al-2.0C-8.0Ti (alloy-4) were prepared by non-consumable arc melting. The arc melted pancakes were examined using scanning electron microscopy, electron probe microanalysis, and X-ray diffraction to understand the microstructure of these alloys. The dendritic solidification structure was observed in alloys 2-4. The microstructure of these alloys also revealed the presence of TiC precipitates, whereas no such phase was observed in alloy 1. The size and volume fraction of these precipitates increased with increase in the concentration of Ti and C. The yield strength of Fe-7 wt%Al alloy at both room temperature and at 873 K increases with increasing carbon and titanium.This may be due to the composite strengthening arising out of increased precipitations of hard TiC precipitates.