A FIRST PRINCIPLES INVESTIGATION OF ENVIRONMENTAL EMBRITTLEMENT OF CO3TI ALLOY

The first principles discrete variational method (DVM) is used to inve stigate the alloying effect of Fe, Al and B on the environmental embri ttlement of Ll(2) Co3Ti alloy. The values of the binding energy, Fermi energy, bond order, directionality of bonding and density of states a re calculated and analyzed. By comparing the results of Fe, Al and B a dditions with those of the undoped Co3Ti alloy, we can examine the eff ects of alloying. The present calculations indicate that the addition of Fe and Al creates a more homogeneous electronic distribution at gra in boundary and makes the grain boundary cluster less reactive with wa ter. The effect of B on the bonding features is also discussed, the an ti-bonding Co-B may suggest that B has little effect on improving the ductility of Co3Ti alloy. Copyright (C) 1996 Acta Metallurgica Inc.