Grain boundaries PDF

ABSTRACT

Helium and hydrogen, atomically dispersed in metallic grain boundaries, tend to drive the adjoining grains apart so as to reduce their Pauli repulsion. Carbon and boron, by contrast, have partly-filled atomic states at about the Fermi energy level of the metal and in a transition metal these can form strong covalent bonds with the valency states of the adjoining atoms, which resist intergranular fracture. The corresponding behaviour of other foreign atoms in boundaries is briefly discussed.

Edited by: I.R. Harris, I.P. Jones