Diffusion annealing of copper–silver bimetallic strips at different temperatures

Copper–silver bimetallic strips prepared by cold roll cladding have been treated by diffusion annealing in the temperature range 250–800 °C. The interface bonding level and the hardness of the matrix copper and silver have been determined and the microstructure in the interface region has been observed. The interface bonding level is particularly enhanced by annealing at 400 and 800 °C. High diffusion anneal temperatures lead to reductions in the strip hardness values. Recrystallization could just be detected in the strips annealed at 250 °C but were much more manifest at 400 °C. Annealing above 600 °C produces fine-grained areas between the interface and the silver matrix. Diffusion anneal treatments that can induce recovery, recrystallization, or partial fusion at the bonding interface can lead to enhancement of the interface bonding level.