Microstructure, phase relationships and microhardness of Fe60Al40-nHfn alloys (n=1, 3, and 5 at.%)

Abstract

The microstructural evolution, solidification behavior, phase relationships, microhardness and room temperature magnetic properties of the hypoeutectic Fe60Al40-nHfn (n = 1, 3, and 5 at.%) compositions are investigated in detail. The microstructure of the studied alloys is composed of Fe-Al based dendrites and eutectic mixture. The components of the eutectic are B2 Fe-Al based and HfFe6Al6 tau(1) phases. With increasing Hf fraction, the amounts of eutectic and tau(1) phases increase continuously which results in significant strengthening. Based on the differential scanning calorimetry results, the eutectic reaction temperature is measured as 1251 degrees C. Fe60Al40-nHfn alloys show weak room temperature ferromagnetism and their magnetization values also increase with increasing Hf content.