Effect of diffusion annealing on microstructure and composition distribution in interfacial regions of silver-copper bimetallic sheets

The microstructure and the solute distribution in the interfacial regions of the cold roll cladding Ag-Cu bimetallic sheets under different diffusion annealing conditions have been investigated. Diffusion annealing at 400 degreesC results in recrystallization in the sheets while that at 750 degreesC makes grain coarsening. At 750 degreesC annealing a fine grain area forms in Ag sides next to the interfaces, the secondary phase precipitates in the fine grain area and the cavities appear along the interfaces. With increasing annealing time at 750 degreesC, the width of the fine grain area and the grain size in the fine grain areas increase. Moreover, the cavities tend to form joint clusters.