The effects of atomic-scale voids upon the strength and mechanical behavior at 0K were investigated by using the total-energy pseudopotential method. Calculations were performed in which the defective system was extended by a small increment, and then was relaxed to its ground-state configuration. The total energy and stress were determined at each strain level. The so-called tensile test of the defective system was compared with the results of experiments on a perfect system. The simulations involved a quantum-mechanical scheme, and revealed deformation processes around the defects; including the initiation of dislocations and slip. They could also be used as a database against which to compare models that were based upon simpler atomic potentials. They were used in that way in order to test a Sutton-Chen model and a pair-wise model. The Sutton-Chen model revealed significant void expansion at about 60% of the failure strain; an effect which was not seen in the  ab initio  calculations. The  ab initio  calculations indicated how empirical models such as the Sutton-Chen scheme might be improved so as to reflect better the nature of metallic bonding.

V.B.Deyirmenjian, V.Heine, M.C.Payne, V.Milman, R.M.Lynden-Bell, M.W.Finnis: Physical Review B, 1995, 52[21], 15191-207