The effects of various Ni contents on the microstructure, melting characteristics and mechanical properties of Ag-22Cu-17Zn-5Sn filler alloy were investigated by optical microscope, scanning electron microscope, energy dispersive spectroscopy, X-ray diffraction, thermal analyzer and tensile testing machine. The results indicate that the Ag-22Cu-17Zn-5Sn-xNi filler alloy is mainly comprised of Ag, Cu based solid solution, Cu0.64Zn0.36 and Cu40.5Sn11 compounds. When the Ni content is increased to 0.6%, the solder microstructure changes from coarse dendritic to uniform fine grains, and its average grain size is about 4.53 μm. As the Ni content increases, the solidus temperature of the solder remains basically unchanged, while the liquidus temperature and the melting temperature range rise in varying degrees. The tensile strength decreases first, then increase and then decreases, and the elongation increases first and then decreases, the hardness of solder (HV0.2) gradually decreases from 140 to 100. When the Ni content is 0.6%, the maximum tensile strength of the solder reaches up to 372 MPa and the elongation increases to 7.6%. |