N.K. Chernov, V.A. Ponomaryov, N.V. Jarantsev
In suggested paper results of explorations on prevention of formation of bubbles under a silver matting enunciated at annealing composition straps: copper-steel-copper-silver (CFeCS) and copper-silver (CS) with streaky (partial on breadth) a matting for lead-frames of cages of integrated circuits (IС), and also strap CS with a continuous unilateral matting for cathodes of electrolytic capacitors.
Now straps CS and CFeCS are fabricated or absolutely without annealings (CS), or with one low-temperature finish annealing (CFeCS) to avoid a bursting expansion of a silver matting. Strap CS intended for cathodes, fabricated by a deep drawing, without a high-grade finish annealing cannot sustain such warp because of low plasticity.
Thickness of an initial aluminium metal paper (0,014 mm) picked radiating from necessity of minimization of influence of a underlayer on physicomechanical properties of a ready composite metal. A underlayer superimposed prestressly on a copper base a method of joint cold rolling on a mill of rolling with a per cent reduction of 44 %.
The picked volume fraction of a underlayer in an initial bundle does not exceed 0,6 % and is in a solubility region of aluminium in copper, which at temperatures interesting us (600... 700°С) makes about 9 %. Therefore annealing of bimetal strip plate copper-aluminium at temperatures 650 … 700°С during 0,5 hours. Gives in the complete transition of thin aluminium in a solid solution in copper of yellow color such as an albronze. Thus losses of plasticity of a course does not occur, what it is possible to judge on absence of a peeling at a wrapping test