This work investigates the effect of bismuth (Bi) addition, 1 wt% Bi, on wettability of the Sn-3.0Ag-0.5Cu (SAC305) ternary Pb-free solder alloy. Adding Bi to SAC305 decreased the contact angles (theta) of the Sn-2.0Ag-0.5Cu-1.0Bi (SAC-1Bi) quaternary Pb-free solder alloy, which were measured by using of the sessile drop method at various temperatures (250, 280 and 310 degrees C) on Cu substrate in argon (Ar) atmosphere. Microstructures, inter-metallic phases and melting temperatures were analyzed by optical microscope, scanning electron microscopy, X-ray diffraction, and differential scanning calorimetry, and effects of the amount of Bi on microstructure were investigated. The experimental results exhibited that when the addition of Bi was 1 wt%, changing in melting temperature of SAC-1Bi solder was insignificant, but the wetting angles (h) of the solder alloy decreased which were measured by using of the sessile drop method at various temperatures. The lowest h was obtained as 35.6 degrees for SAC-1Bi alloy at 310 degrees C. (C) 2018 Karabuk University. Publishing services by Elsevier B.V.