Effect of Ti, W, Mn, Mo and Si on microstructure and mechanical properties of high carbon Fe–10·5 wt-%Al alloy

Abstract

Effect of quaternary alloying elements Ti, W, Mn, Mo and Si on the microstructure and mechanical properties of Fe–10·5Al–0·7C (wt-%) alloy has been investigated. Six different alloys were prepared by a combination of air induction melting with flux cover and electroslag remelting (ESR). The composition of the quaternary alloying element was ∼2 wt-% and was substituted for iron. The ESR ingots were hot forged and hot rolled at 1375 K. The hot rolled alloys were characterised with respect to microstructure and mechanical properties. Alloys containing W, Mn and Si exhibited two phase microstructure of Fe3AlC0·5 precipitates in α Fe–Al matrix. Whereas alloys containing Mo and Ti exhibited three phase microstructures, the additional phase being the respective carbides. Both α Fe–Al matrix and Fe3AlC0·5 precipitates have considerable amount of solubility for W, Mn and Mo whereas Si has very high solubility in α Fe–Al matrix as compared with Fe3AlC0·5 precipitates and titanium has very low solubility in both α Fe–Al matrix and Fe3AlC0·5 precipitates. Greater improvement in room temperature tensile properties was observed by the addition of Mn as compared with the addition of W. Significant improvement in tensile and creep properties was observed by the addition of Mo. Though the addition of silicon has resulted in poor room temperature ductility, there has been remarkable improvement in high temperature strength and creep properties.