Rapid-solidification phenomena

Abstract

A series of alloy powders has been compacted using the dynamic powder compaction process and the regions of rapid melting and solidification formed studied in detail. Technologically, such regions are of importance because they represent the bond regions between particles where microstructural transformations are most likely to occur. In the present context these regions are important because they represent microsamples which have suffered extreme, but reasonably well defined, changes of physical state and, most notably, have solidified under extremely high and deducible cooling rates. The microstructures found within these microsamples have been examined and the relevance of the commonly used relationships between microstructure size and cooling rate discussed.