USS are likely due to short time of annealing. The central part of the joint is still unreacted In-48 at.% Sn which makes diffusion-soldering to be uncompleted.
ExperimentalHigh purity components In and Sn (99.999 wt%) were melted in appropriate amounts and cold rolled to obtain thin (LM) foil of In-48Sn eutectic alloy. Copper was used as the base (HM) material. Prior to soldering, Cu surfaces were grinded and thin foil was clamped between two Cu pieces and diffusion-soldered without any inert atmosphere. The sample geometry for the shear test together with its photo is presented in Figure 4.Both joint cross-sections before the test and fracture surface after it were investigated by means of light (Laica) and scanning electron microscopy (SEM) (Philips XL 30). Moreover, the chemical analyses were performed by means of SEM equipped with energy dispersive X-ray spectrometer (EDX) (Link ISIS).The shear tests were performed on the INSTRON 6025 instrument in the room temperature with the displacement rate of 0.2 mm/min. Final version: November 22, 2005 -[1] Directive 2002/95/EC, Official J. of Eur. Union. 13 Feb.