Formation of structure in the zone of internal oxidation in copper-base alloys

Abstract

The development of structure in the internal-oxidation zone of binary alloys formed between copper and various oxide-forming elements (Al, Be, Ti, or Si) as a result of the diffusion of oxygen into these is considered; so is the effect of small quantities of third elements on the process. As the internal-oxidation zone advances the size of the precipitates increases; in the presence of preferential crystallographic directions of growth, acicular precipitates develop, and a microscopically banded structure is created. The reason for the structural characteristics indicated apparently lies in the changing ratio of the number of oxygen atoms to the numbers of atoms of the oxidizing element at the reaction front as the latter advances. The addition of traces of third elements (Ti to Cu-Al, Be, Ti, and Zr to Cu-Si) affects the nucleation process and increases the degree of dispersion of the precipitates. This influences the diffusion of the reacting elements and hence the character of structure formation.