Mechanical properties of a lead-free solder alloys

Lately, environmental problems have gained more and more attention from many countries; because of environmental pollution from lead-based solders and compounds, many countries are about to prohibit the using of lead-based solders in microelectronic packaging; lead-free solder alloys will replace tin-lead (Sn-Pb) eutectic solders. However, the mechanical properties of lead-free solders have not been clarified The tensile property of Sn96.5Ag3Cu0.5 was investigated. The tensile strength of this lead-free solder was obtained at 25°C, 50°C, 75°C, 100°C, 125°C and 150°C; the tensile strength of the lead-free solder decreases with increasing test temperature at a constant strain rate. The tensile strengths of a lead-free and a lead-based solder were compared, and the tensile strength of Sn96.5Ag3Cu0.5 was found to be close to that of Sn63Pb37; this lead-free solder has some good mechanical properties, and will be a promising candidate solder alloy in microelectronic packaging.