ask aluminium Forum

i did a bunch of searches & couldn't find this.  In various other uses, "garbage alloy" means low strength, so my hypothesis is that this alloy is low cost & low quality, suitable for use in undemanding applications.  

All the sites I found that compare tensile strengths of aluminum alloys code the alloys with a different scheme, e.g., 6005 Aluminum.  If you know the 4 digit code for ADC12, you can check my hypothesis.

 I suspected that ADC12 is used in beverage cans, which wind up in the garbage.  I found
Modern  cans are generally produced through a mechanical cold forming process  that starts with punching a flat blank from very stiff 
cold-rolled sheet. This sheet is typically alloy 3104-H19 or 3004-H19, 
which is aluminium with about 1% manganese and 1% magnesium

and
Aluminium beverage cans are fabricated from two parts:
the can body, generally made from EN AW-3104 sheet),      and
the can end, typically made using EN AW-5182 due to      its higher strength.

ADC12 is a recycled alloy. Hence people call it a Garbage alloy. It is a cast alloy, and it cannot undergo larger plastic deformations, as it contains high silicon and iron impurities. Hence cannot be used for applications like beverage cans.