Wish I had my scanner ready, lots of data. Terry is Correct.

6061 consists of :
0.4-0.8 Si, 0.7 Fe, 0.15-0.40 Cu, 0.15 Mn, 0.8-1.2 Mg, 0.04-0.35 Cr,
0.25 Zn,0.15 Ti, total variance .05 ea and 0.15 total all. Rest is Al.

Mostly AL.

Now there are special versions of 6061 that are called 6061/Si-C/47f
which is the AA-registered alloy 6061 reinforced with 47% vol of
continuous Si-C fibers. A special version indeed.

The Mg and Mn indicate work hardening alloy.
Mixing Cu or Cu-Mg or Mg-Si or Zn-Mg Zn-Mg-Cu - age hardening.

Metals Handbook, second edition, Desk Edition,
75 Anniversary ASM Handbooks.

Martin

On 5/26/2016 3:31 PM, Terry Coombs wrote:
Steven wrote:
replying to pogo, Steven wrote:
The first digit is the alloy type second digit is the modification of
the alloy and the last two digits are the purity of the aluminum so
6061 means that in this case magnesium and silicon were added to the
aluminum and that it was not modified and it is 61 percent pure
aluminum

Bull**** , look it up . 6061 is approx 95% aluminum .