6061 isnt a bad material at mountain cycle mucho 6061 – 6069 aluminium was used mainly it was cheap and good for what it was being used for and available abundently if we wanted 7 series it was custom drawn and 3 times the price
There are some drawbacks to using any 7000 alloys in the weldable range and more to be had as you get to near to the 7050 range materials which need to be doped if you want to weld them
6061 is a good tough all round aluminium it doesn’t suffer from some of the freakish occurences as with 7xxx material
sometimes even if your using 7000 series to get it to resist certain freakiness there needs to be an oveageing process to securely make sure it isn’t going to die prematurely this in itself reduces the materials suceptability to freakiness but also reduces its ultimate strength by 15% so its the same as not heat treating so its just a different animal…anodize it it becomes a different animal again
theres lots of little numbers after aluminium for example 6083 slightly different to 6061 but different properties
the taiwanese liked to get rid of the heat treat cycle its an extra cost
but then it also has its benefits
heat treating is a bit of an art in itself and writing off a bunch of bannana shaped frames isn’t an option really
of course the devil is in the details and you can design some pretty shit hot stuff if you know what your material is going to do