Abstract
The effect of adding TiO2 nanoparticles as well as aging time on the thermal, microstructural and creep properties of Sn-6.5Zn solder was studied. The Sn-6.5Zn composite solders were prepared by mechanically dispersing different weight percentages (0.0wt.%, 0.25wt.%, 0.50wt.%, 0.75wt.% and 1.0wt.%) of TiO2 nanoparticles into Sn-6.5Zn solder. After being solution heat treated at 453 K for 4h, specimens were cooled by water quenching at 273 K. Specimens were artificially aged at 393 K for durations ranging from 15 to 120 min, followed by water quenching at 273 K to cease further aging. The thermal behavior of the composite solders was investigated using differential scanning calorimetry (DSC). X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to observe the microstructure of the solders. The mechanical properties were characterized using tensile creep tests and correlated with microstructural features. The investigation revealed that the minimum creep rate of solders decreased with the increase in the content of TiO2, while it increased with increasing aging time. The data from microstructure-properties analysis showed that the nano-TiO2 particles had significantly refined the microstructure and improved the creep resistance in comparison with the Sn-Zn solder. The calculated stress exponent values were close to 7.