Phase stability and mechanical properties of Fe3Al with addition of transition elements

The mechanical properties of D03-type (Fe1 − xMx)3Al alloys with M = Ti, V, Cr, Mn and Mo have been investigated using a Vickers microhardness indentation technique. Electrical resistivity measurements demonstrate that the substitution of M = Ti, V and Mo results in a remarkable stabilization of the D03 structure relative to the B2 structure, probably because of the site preference of the substituents. At temperatures above 600 K, the hardness increases with increasing temperature and reaches a maximum at around 800 K. The anomalous peak in hardness extends to higher temperatures in parallel with increase in the D03-B2 phase transformation temperature. In particular, the substitution of M = V leads to a significant improvement in the high-temperature strength up to 1000 K and above, maintaining the peak hardness almost constant.