Effects of aging time, strain rate and solder thickness on interfacial fracture behaviors of Sn–3Cu/Cu single crystal joints

The effects of aging time, strain rate and solder thickness on fracture behaviors of Sn–3Cu/Cu single crystal joints were investigated. Experimental results showed that short aging time (less than 10 days) did not obviously affect the tensile strength and fracture behaviors of the solder joints. However, strain rate and solder thickness played significant roles in the strength and fracture behaviors of the solder joints. It was observed that these joints broke in a ductile manner at low strain rates with a rapid increase in the tensile strength, but displayed a brittle manner at high strain rates with a slow increase in the tensile strength. A model was proposed to explain such ductile-to-brittle transition between solder and intermetallic compounds. In addition, the solder joints broke in a ductile manner and presented a low tensile strength for the joints with thicker solder, but displayed a brittle manner and a higher tensile strength for the joints with thinner solder.