Abstract:Ag-Cu-Ge eutectic solder ribbons were prepared by single roller rapid solidification. Melting temperature and phase composition of solder alloys were determined by DSC and XRD. The microstructure and morphology of solder alloys and brazing joints were observed by scanning electron microscope (SEM), and the chemical composition was analyzed by energy dispersive spectrometer (EDS). The results show that the liquidus temperature of rapidly solidified Ag-Cu-Ge solder decreases 4.8℃ and its melting temperature range reduces 4.4℃. The microstructure of cast solder is massive and heavy segregation, while rapidly solidified solder has finer microstructures and higher composition homogeneity; Rapidly solidified Ag-Cu-Ge solder has a better wettability and spreadability, wider transition layer thickness and higher shear strength of brazed joints with Cu and Ni substrate compared with the same constituent common solder. Congruent compounds which grows up as a layer is found on the interface of solder alloy with copper substrate, while incongruent compounds which grows up as bamboo shoot form is found on the interfaces of solder alloy and substrate. This embedded structure is helpful to improve the strength of brazed joints