An electronic-level phenomenological theory was developed in order to predict the effect of a substitutional alloying addition upon grain-boundary cohesion. It was based upon first-principles full-potential linearized augmented plane-wave calculations. Upon using the bulk properties of the substitutional alloying addition, A, and the matrix element, M, as inputs, the strengthening or embrittling effect of A at a grain boundary of M could be predicted, without carrying out first-principles calculations, once the atomic structure of the corresponding clean grain boundary had been determined. Predictions were made of the embrittling power of a large number of metals, including 3d, 4d and 5d transition metals, with respect to Σ = 5 (210)Ni grain boundaries. Rigorous calculations of the effect of Ca on the Σ = 5 (210)Ni grain boundary, confirmed the predictions of the model. The latter was expected to be applicable to other high-angle boundaries.

Influence of Alloying Additions on Grain Boundary Cohesion of Transition Metals - First-Principles Determination and its Phenomenological Extension. W.T.Geng, A.J.Freeman, G.B. Olson: Physical Review B, 2001, 63[16], 165415 (9pp)