Effect of heat treatment on the fracture and structure of tin-indium solder alloy

The effect of heat treatment on the structure, hardness, and electrical resistivity of the crystalline Sn100-x In-x (x=10 wt.%) solder alloy is studied. The structures of as-casted and heat-treated alloys have been investigated by means of a X-ray diffraction technique. Using X-ray analysis a crystalline beta-Sn and an In phase are detected. The amount of the crystalline phases increases upon increasing the annealing temperature. It is found that the fracture is delayed from 8.6 kg/mm(2) at 50 s and 100 g at room temperature to 4 kg/mm(2) at 90 s and 100 g at 423 K. Differential thermal analysis was used to investigate the melting characteristics of the alloy (m.p. similar to 214 degrees C). The resistivity is also determined for samples thermally and non-thermally treated.