Creep in Shear of Experimental Solder Joints

Abstract

Thermal fatigue failures of solder joints in electronic devices are a great concern in the electronics industry. Since the fatigue load is often in shear the details of thermal fatigue failure in shear are of particular interest. Recent work indicates that similar failure mechanisms operate in both thermal fatigue in shear and unidirectional creep in shear. Additionally, since the operative temperatures during thermal fatigue represent high solder homologous temperatures, creep deformation is certainly involved. These factors and the relative case of conducting creep experiments encourage the study of solder joints under shear creep conditions. This work presents steady state shear creep rate vs. shear stress data for several solder compositions, including the binary eutectic alloy and Pb-Sn alloyed with small amounts of Bi, Cd, In, and Sb, in a joint configuration. These data indicate that conventional creep mechanisms operate in the temperature and shear strain rate ranges studies. Extensive microstructural information is also reported. The microstructural evolution under creep conditions indicates that the instability of the as-cast binary Pb-Sn eutectic microstructure initiates creep failure. Changes of the as-solidified microstructure with the third element addition are reported as are the microstructural responses of each of these alloys to creep deformation. The efficacy of postponing the microstructural instability with the addition of small amounts of ternary elements is discussed.

A hybrid approach to characterization and life assessment of trilayer assemblies of dissimilar materials under thermal cycles

“…Equation ( 5) is a simplified form of Dorn's creep law, which includes the temperature dependence of the hardening mechanism. Equation ( 6) is the Garofalo or hyperbolic sine creep law, which can represent two different creep mechanisms at different stress levels [36,48,52,53,54,55,56]. Wiese et al [34] described the steady state creep of solders by using the power law (Equation ( 5)) to formulate the climb-controlled behaviour at low stress magnitudes and the combined glide/climb behaviour at high stress values.…”

Comparative study on stress–strain hysteresis response of SAC solder joints under thermal cycles

“…Equation 4 is a simplified form of Dorn's creep law, which includes the temperature dependence of the hardening mechanism. Equation 5 is Garofalo or hyperbolic sine creep law, which can represent two different creep mechanisms at different stress levels (Chen et al 2004;Tribula and Morris 1990;Kariya et al 2001;Kluizenaar 1990;Harada and Satoh 1990). Wiese et al (2001) described the steady state creep of solders by using the power law (Eq.…”

Microstructural Investigation of Sn‐Ag and Sn‐Ag Solder Joints*

“…Extensive research has been carried out in the last decade on the creep and creep/fatigue behaviour of solder joints 12345678910. In contrast, only limited attention has been focused on the effect of processing parameters on the as‐soldered microstructure 911.…”