Microstructural evolution and shear strength of AuSn20/Ni single lap solder joints

► The AuSn20 solder is prepared by laminate rolling-annealing method. ► Eutectic microstructure and (Ni, Au)3Sn2 phase form in reflowed AuSn20/Ni joint. ► Formation of (Ni, Au)3Sn2 consumes the potential δ-phase in solder matrix. ► The shear strength of single lap joints decreases as aging at 150 or 200 °C. ► Coarsen microstructure has notable effect on the reduction of shear strength.