DYNAMIC SCALING THEORY OF SPLAT COOLING FOR RESULTING THICKNESS EVALUATION

A general model is presented for splat cooling which lends itself to l inear and to non-linear thermal exchange at the sample-substrate inter face. Thermal conduction in the melt is considered to take place via p honons and electrons. The theoretical approach is developed generally, using some elements of the earlier Miyazawa and Szekeley model, and u sing the Jaeger solutions of the temperature distribution for a static semi-infinite medium, by scaling under the dynamic conditions of the splat. The theory is tested, for the case of newtonian cooling, by com parison with the results of Kroeger et al. We find good agreement betw een the theoretical predictions of our model, and their experimental d ata for the splat thickness of splat cooled Cu-45%Zr, Nb-45at%Rh and T a-45at%Ir alloys, for plausible values of the heat transfer coefficien t. In particular we eliminate an unnecessary parameter introduced prev iously to obtain agreement with these experimental data. A comparison is finally made between the calculated temperature distributions for a hypothetical but realistic melt, employing the linear newtonian and t he non-linear Stefan-Boltzmann thermal exchanges.