Influence of SiC nanowires on the microstructures and properties of Ag–Cu–Ti filler metals and brazed joints

Abstract

Ag–26.7Cu–4.5Ti filler metals with different contents of SiC nanowires were prepared to analyze the effect of SiC nanowires on the microstructures, melting temperature, wettability, shear strength and fracture morphology of brazed joints. The results indicate that a small amount of SiC nanowires ([Formula: see text]0.1%) can refine the matrix microstructure and reduce the Cu–Ti intermetallic compounds, which can induce the increase of shear strength of brazed joints with 46.7% maximum amplitude, the ductile pattern is the main fracture mode for Ag–Cu–Ti–1.0 SiC brazed joints. Moreover, the SiC nanowires can improve the spreading are of Ag–Cu–Ti filler metals on steel substrate with a 9.4% increase amplitude, when the content of SiC nanowires is more than 0.1%, the wettability can be reduced obviously. The addition of SiC nanowires can show little effect on the melting temperature, which results in the same brazing temperature for Ag–Cu–Ti–[Formula: see text]SiC filler metals. With the optimization content of SiC nanowires, the optimal content of SiC is 0.05–0.1%, excessive SiC addition with agglomeration can decrease the wettability and shear strength.