Microstructure evolution and thermal, wetting, mechanical properties of SiC nanowires reinforced SAC105 composite solder

In this paper, SiC nanowires (NWs) were added to the SAC105 solder as an enhancement agent. By mechanical stirring, the Sn1.0Ag0.5Cu (SAC105)-xSiC (x = 0, 0.2, 0.4, 0.6, 0.8, 1.0 wt%) solders were prepared and served as samples to investigate the thermal properties, wettability, microstructure, interfacial microstructure, and mechanical properties. It was found that the addition of 0.4% SiC NWs allowed a substantial increase in the spreading area. The Cu6Sn5 IMC and Ag3Sn IMC, and β-Sn grains were significantly refined within the SAC105-0.6SiC solder matrix. Meanwhile, the interfacial morphology became much flatter, and the thickness was minimized. Due to the refinement of Ag3Sn IMC and the reduction of the interfacial thickness, the mechanical properties of the composite solder were unsurprisingly improved. These were well demonstrated by the deeper and smaller dimples derived from the fracture surface. In addition, the mechanisms of microstructure refinement and enhancement of mechanical properties were revealed from the aspects of dispersion, adsorption, and pinning effect of SiC NWs. The deterioration of solder properties due to the agglomeration of SiC NWs was also well discussed.