Solder Constitutive Equation and Thermal Fatigue Reliability Prediction

Solder Constitutive Equation and Thermal Fatigue Reliability Prediction 

Data are shh emerging from different studies on the parameters for the constitutive equation for lead-free solder alloys (for example. Refs 9- 

The effort is complicated by the high strain-rate sensitivity (strain hardening), and the temperature sensitivity of the Sn-Ag-Cu alloy (Ref 

Complicating the situation further is the different stress dependency of the creep rates for Sn-Ag-Cu and Sn-Pb eutectic alloys (Ref 11), leading to different comparisons between the two alloys at low and high stress levels (Ref 12-13). Recent studies (Refs 11 and 14) also suggest that both primary creep and tertiary creep are important for the Sn-Ag-Cu alloy. Such considerations are particularly important for high reliability applications (such as aerospace, automotive, military, etc) and long life products (such as telecommunication infrastructure equipment). 

For fatigue life prediction, materials parameters need to be established to correlate the number of cycles for thermal fatigue life to the 

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