Mechanical behaviors of 60/40 tin-lead solder lap joints

The authors present monotonic, fatigue, and creep-fatigue data for 60/40 tin-lead solder lap joints at room temperature. Monotonic tests performed include rapid-strain shear, creep, and stress relaxation tests. Fundamental data are presented for the strain range partitioning (SRP) approach to creep-fatigue life prediction. SRP is found to model the solder creep-fatigue response adequately for the range of frequencies (0.007 to 0.5 Hz) and waveshapes tested. The elastic modulus and Poisson's ratio were determined to be 38.6 GPa and 0.36, respectively. Thorough experimental and numerical analyses of a sample 60/40 tin-lead solder lap joint revealed a complex strain state along the solder-copper interface. Fatigue lives for 0.5-Hz tests performed under load control correlate with the lives to 50% load drop for tests performed under strain control.<
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