The Effect of Annealing Temperature on the Bond Strength and Structure of Interface in Ag/Cu Strips

Copper–silver bimetallic strips were produced by cold roll welding process and were treated by diffusion annealing in the temperature range 250–800 ?C. The interface bonding strength was determined by bending and peeling tests, Resistance, conductivity and micro hardness profiles were determined and microstructure in the interface region was observed by optical microscope.
Electrical resistance and bonding strength in the interface depend on the diffusion annealing temperature. Diffusion annealing above 600 ?C produces fine-grained eutectic phases in the interface region and silver matrix.
The eutectic phase formation and the movement of interface is a chemical–diffusion process. It is observed that the strength is greatly reduced by increasing the thickness of eutectic compounds. These compounds have detrimental influences on physical and mechanical properties of the interface. The results indicate that there is an optimum annealing temperature at which the sheet exhibits a satisfactory formability together with a high bonding strength.