Rapid solidification of Cu60Co30Cr10 alloy under different conditions

Abstract

Metastable liquid phase separation and rapid solidification in a metastable miscibility gap were investigated on the Cu60Co30Cr10 alloy by using the electromagnetic levitation and splat-quenching. It is found that the alloy generally has a microstructure consisting of a (Co,Cr)-rich phase embedded in a Cu-rich matrix, and the morphology and size of the (Co,Cr)-rich phase vary drastically with cooling rate. During the electromagnetic levitation solidification processing the cooling rate is lower, resulting in an obvious coalescence tendency of the (Co,Cr)-rich spheroids. The (Co,Cr)-rich phase shows dendrites and coarse spheroids at lower cooling rates. In the splat quenched samples the (Co,Cr)-rich phase spheres were refined significantly and no dendrites were observed. This is probably due to the higher cooling rate, undercooling and interface tension.