Comparative study of tensile creep behaviour of lead-free solder alloys and conventional Sn–Pb solder

Purpose This work is an investigation of the tensile creep behavior of the conventional tin-lead (Sn−40Pb) solder and three Pb-free solders, tin−copper (Sn−0.7Cu), tin−zinc (Sn−9Zn) and tin−zinc−copper (Sn−49Zn−1Cu), to find an appropriate green substitute for industry use. Design/methodology/approach Tensile creep tests were conducted on Sn–40Pb, Sn–0.7Cu, Sn–9Zn and Sn–49Zn–1Cu alloys under uniaxial stresses of 10, 13 and 17 MPa. The study primarily focuses on the creep behavior of these solders, including the evolution of creep stages, steady-state creep rates and resistance to tertiary creep, also the abrasive wear surface of the alloys studied under scanning electron microscope (SEM). Findings The Sn–49Zn–1Cu had the best creep resistance and smallest steady-state creep rate among the studied solders, while Sn–0.7Cu was most prone to creep and Sn–9Zn exhibited medium property. At high stress levels, Sn–49Zn–1Cu did not exhibit tertiary creep as the other alloys did. A power-law relationship between minimum creep rate and applied stress was established for all materials. SEM observations on the worn surfaces showed that Sn–49Zn–1Cu had a more homogeneous structure with shallower grooves and less defects, which was interpreted as better wear resistance and microstructural stability. Originality/value This study presents a comparative assessment of the tensile creep behavior of Pb-free solder alloys relative to conventional Sn–40Pb solder. The findings indicate that the Sn–49Zn–1Cu alloy demonstrates superior creep resistance, highlighting its potential as a reliable and environmentally friendly alternative for applications that require improved long-term mechanical stability.