CALCULATIONS OF SYSTEMATICS IN B2 STRUCTURE 3D TRANSITION-METAL ALUMINIDES

An all-electron total energy local density functional approach was use d to examine features in the electronic structure of B2 structure tran sition metal aluminides that are possible factors affecting brittlenes s in these intermetallics. Noting that iron, cobalt and nickel all for m stable aluminides with nearly identical lattice parameters, yet mani fest different physical properties, we compared calculated results for B2 FeAl, CoAl, NiAl and CuAl, with an eye toward elucidating those fe atures that correlate with the observed physical properties. The first -principles calculations accurately reproduced the formation energies of these compounds. Detailed analyses of the results explicitly demons trated that factors commonly associated with bonding and brittleness i n intermetallics-valency, ionicity and directional bonding-cannot in f act be the critical factors governing the behavior of these materials.