Discontinuous precipitation in Copper Cobalt Alloys

Abstract

<p>This thesis is concerned with the cooperative growth problem of the discontinuous precipitation reaction of rod-like particles and their subsequent spheroidization into rows. Previous theories are examined, and the details of a model for the transformation, which assumes the existence of local equilibrium between the product phases,are derived. The steady state diffusion equation is solved under the assumption of boundary diffusion controlled growth in the case of rod symmetry. The available kinetic data and auxiliary information are used to test the model. The results are consistent with the premise that a boundary friction term determines the rate of interface migration. The electron microscopy is used to determine the precipitate morphology and their size and distribution. The results are interpreted in the light of existing knowledge and concepts especially developed for the purpose of this investigation.</p>