Abstract:Four compositions of alloys were designed. They were Cu-2% In, Cu-7% In, Cu-11% In and Cu-23% In (mass fraction). These alloy specimens were prepared by metal mold. By means of microstructure observation, macrostructure observation and electron probe analyzing, microstructures and macrostructures of the specimens were analyzed by comparison method. Microstructure component and relationship between structure and composition of alloys were investigated. The results show that with increasing indium content, the grain changes from columnar one to equiaxed one, the equiaxed grain increases, the columnar grain zone decreases and the grain size becomes small. With increasing indium content, the growth way changes from planar one to dendritic one. Peritectic reaction plays inhibiting role on the growth of dendrite and affects the orientation of dendrite. Indium content has influence on lattice constant of Cu solid solution.

Key words: Cu-In; mircrostructure; composition