Some Fundamental Considerations During Rapid Solidification Processing

ABSTRACTThree estimates of the solidification rates required to obtain a fully homogeneous structure during rapid solidification processing (RSP) have been made. One is given by the “absolute stability” criterion and another obtained from a new analysis for dendritic solidification. The third estimate, also derived from the above analysis, requires that “hypercooled” conditions be maintained after nucleation. A mechanism for the formation of “featureless” segregation-free zones during melt spinning and atomization processes is suggested and expressions for the critical cooling rate and thermal gradient required to produce such structures have been obtained.