Liquid and solid phase separation during melt spinning and annealing in melt-spun Cu–Cr ribbons

Abstract

Cu 1− X –Cr X ( X = 2–35 wt.%) ribbons were prepared by melt spinning. The microstructure examinations revealed that depending on the compositions, the liquid phase separation occurred inevitably in Cu–Cr melts during melt spinning. The size of Cr particles from liquid phase separation increased with Cr content increasing when the ribbons contained less than 20 wt.% Cr. However, the size increased a little when the Cr content increased from 25% to 35%. The Cu matrix of the as-quenched ribbons was supersaturated. It separated rapidly during annealing at 773–1173 K. All the coherent and incoherent precipitates were observed in the annealed ribbons. The size of precipitate particles was not dependent on the annealing time strongly. The liquid phase separation Cr particles played an important role in the separation of supersaturated solid solution. When the spaces between these particles were very small, the separated Cr atoms would diffuse to the interface between Cu matrix and Cr particles from liquid phase separation. Otherwise, fine Cr particles in nano-size precipitated in the Cu matrix.