THE COMBUSTION SYNTHESIS OF COPPER ALUMINIDES

The formation of Cu-Al alloys by the thermal explosion mode of the combustion synthesis method was investigated for compositions ranging from 25 to 50 at. pct Al. Through X-ray, differential thermal analysis (DTA), and scanning electron microscopy (SEM) analyses, the nature of the reaction between powders of the two metals was determined. Solid-state diffusional reactions preceded the main combustion reaction which, in turn, was triggered by the appearance of a liquid phase. The relative amounts of phases formed through solid-state and liquid-phase reactions depended on heating rate. A significant amount of volume growth is observed during the solid-state reaction stage, and it is concluded that it is caused by pore formation by the Kirkendall effect. © 1990 The Minerals, Metals & Material Society.