Effect of transition-metal substitution on electronic and mechanical properties of Fe3Al: First-principles calculations

First-principles method based on the density functional theory was introduced to investigate the effect of impurity Cr or Ni on the site preference, mechanical properties of Fe3Al. Formation enthalpy calculations show that Cr atoms prefer to stay at FeI sites while Ni atoms occupy FeII sites. Our investigations find that Fe2NiAl has lower B/G (bulk modulus/shear modulus) and Poisson’s ratio compared to other (Fe3−yXy)Al alloys, which turns out to be a brittle alloy. The analysis of density of states and charge population indicate that the plasticity of Fe3Al can be improved by transition-metal doping.

► Cr prefers to stay at FeI sites while Ni likes FeII sites.
► TM-substituted modify the hardness of Fe3Al.
► TM element doping cause more ionic for Fe–Al alloy.
► D bands play the dominant role in the DOS.