The electronic industry is making substantial progress toward a full transition to Pb-free soldering in the near future. At present, the leading candidate Pb-free solders are near-ternary eutectic Sn-Ag-Cu alloys. The electronic industry has begun to study both the processing behaviors and the thermo-mechanical fatigue properties of these alloys in detail in order to understand their applicability in context of current electronic card reliability requirements. In recent publications, the solidification behavior of the near-ternary eutectic Sn-Ag-Cu alloys has been reported in terms of the formation of large Ag 3 Sn plates and their effects on mechanical properties of Pb-free solder joints. Several methods have been employed to minimize the growth of the large Ag 3 Sn plates in the Sn-Ag-Cu solder joints by controlling the cooling rate during solidification, reducing Ag and/or Cu content, or adding minor alloying elements which reduce the amount of undercooling required for the nucleation of tin dendrites. In the present study, the results of accelerated thermal cycle fatigue tests are reported with the near-ternary eutectic Sn-Ag-Cu alloys of reduced Ag contents. Changes in microstructure and mechanical properties are also discussed by comparing the solder joints before and after thermal cycling.

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Tow Prepreg is the intermediate material for filament winding process that has been "pre-impregnated fiber tow" with resin system. As "dry filament winding" process emerges as a reliable alternative to conventional filament winding (called "wet filament winding") process, interest in tow prepreg as a material for dry filament winding is rising as well. In this article, we have reviewed the recent research trends in carbon fiber tow prepreg for high-performance rocket motor cases, fuel tanks for hydrogen vehicles and other high-quality commercial pressure vessels.

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