Effect of adding nano-sized particles on thermal, structural and mechanical properties of some Sn-Ag-Cu-based solder alloys

Abstract

The aim of the present thesis basically is to investigate the effect of adding Zn as a fourth addition and GONSs as a fifth addition on the thermal, structural and mechanical characteristics of Sn-1wt%Ag-0.5wt%Cu (SAC105) solder alloy. Also, the present work mainly covers studying the effect of strain rate ε•, and testing temperatures, Tt on the stress-strain and stress relaxation characteristics of SAC105 plain, SAC105-1wt%Zn and SAC105-1wt%Zn-0.2wt%GONSs composite wire samples. The effect of different levels of stress and testing temperature on creep characteristics of the three solder alloys was studied.

To study the thermal characteristics, thermal analysis of SAC105, SAC105-Zn and SAC105-Zn-GONSs were discussed. Thermal properties of the selected solder alloys have been studied by using the differential scanning calorimetry (DSC). The results showed that the observed endothermic peaks of the SAC105 plain solder, SAC105-Zn containing and SAC105-Zn-GONSs composite solder were found shifted from two peaks at 494.23 K and 501.21 K for plain solder to one peak at 487 K for composite solder. Thus, the addition of Zn and GONSs influences the melting point of the SAC105-Zn and SAC105-Zn-GONSs solder alloys.

To study the structure characteristics, the microstructure was examined by X-ray diffractometry (XRD), optical microscope (OM), energy dispersive X-ray spectrometer (EDS) and scanning electron microscopy (SEM). XRD pattern for GONSs and bright field transmission electron microscope for GONSs showed an average length of nano-scale with ~20 nanometers. EDS and SEM analysis for the plain and composite solder alloys confirmed that the solder used was SAC105 and SAC105-Zn-GONSs, and th