AN ANALYSIS OF THE CRITICAL CONDITIONS FOR DIFFUSION-INDUCED VOID FORMATION IN NI-CU LAMINATE COMPOSITES

An analysis that predicts, based on Kirkendall porosity formation, the critical composition difference that can exist without diffusion-indu ced porosity formation in laminate composites between solid-solution a lloys is presented. Predictions based on laminate composites fabricate d from pure nickel to nickel-copper solid-solution alloys indicate tha t porosity formation should be suppressed if the copper content in the solid-solution layer is below 40 at.%. The predictions are verified w ith metallographic observations on a series of annealed laminate compo sites. The implications of this study on the stability and mechanical properties of composites at high temperatures are discussed.