QUANTITATIVE STUDY OF Sb GRAIN BOUNDARY SEGREGATION IN RAPIDLY QUENCHED Cu-Sb ALLOYS

In the present work, we used Cu-Sb alloy system as a model to study grain boundary segregation in specimens prepared by rapid quenching. Ribbons of Cu-Sb alloys of single Cu phase and polycrystalline structure containing 0.01, 0.08, and 2wt% Sb prepared by single roller melt spinning were used as specimens, and the segregation was studied by using energy dispersive X-ray spectrometer attached to a scanning transmission electron microscope. Sb grain boundary segregation was detected in the 0.08 and 2wt% Sb specimens and the degree of segregation in the CHUNFEI LI et al. 30 0.01wt% Sb specimen is below detection limit. The effect of rapid quenching in suppressing the segregation was confirmed by comparing the results of asquenched and annealed 0.01wt% Sb specimens. It is reasoned that the degree of grain boundary segregation increases with Sb concentration from zero up to a value larger than 0.08wt% in the present alloy series. Further, it is concluded that the segregation happens at temperatures above 873K. Upon comparing with previous reports, it is concluded that the degrees of Sb grain boundary segregation observed in the as-quenched 0.08wt% Sb specimen have little effect on the alloys performance in impact test. The present work provides a basis of consideration when both annealing and segregation are concerned in alloy processing.