中國有色金屬學(xué)報(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 22 No. 2 February 2012 |
Ag/Al bimetal produced by cold roll welding
（1. Material Science and Engineering Department, Islamic Azad University, Karaj Branch,
P. O. Box 31485-313, Karaj, Iran;
2. Metallurgical Engineering Department, Iran University of Science and Technology,
P. O. Box 31485−313, Narmak, Tehran, Iran）
Abstract:Aluminum and silver strips were cold welded by rolling and a bimetallic strip was produced. To create cold weld between Al and Ag, mating surfaces were specially prepared and various rolling thickness reductions were applied. The minimum critical thickness reduction to begin cold weld was specified as 70% which equals 0.1630 critical rolling shape factors. The bimetallic strips were treated by diffusion annealing at 400 °C and various annealing time. The Al/Ag interface of strips was observed by scanning electron microscope to investigate the formation of hard and brittle probable phases. The effect of anneal time on diffusion distance and phase transformation was also analysed by EDS analysis and line scan. A diffusion region along the interface in the Ag side was observed and its width increased with prolonging annealing time. Some δ phases were detected close to the interface after anneal treating for 3 h and δ phase was thicker and more continuous by increasing annealing time. The microhardness measurement showed that in spite of formation of δ phase due to diffusion annealing, the interface hardness was reduced.
Key words: Ag/Al bimetallic strip; cold weld; anneal; multilayer composite sheet; shape factor
