I'm working on the design for some light weight high mobility plate armor and need a light metal that is still quite sturdy? Being that I am new smithing I need some help on choosing my materials.

 

It's not necessary to stop bullets, my life isn't that messed up, but it would be nice if it could stop most melee attacks without bending or breaking

What kind of protection are you looking for? I'd imagine that could make a world of difference in what alloy and thickness you might want/need to use. I don't know much about armor but there are some here who can help.

Melee attacks with WHAT?

Strongly suggest you take this over to armourarchive.org where they specialize in armour and can discus hardened 1050 vs T6 Al vs Ti vs Barrel Plastic or Kydex., vs ....

We generally use bowstaffs, sometimes swords, occasionally a mace. We try to avoid lethal weapons but they still hurt like xxxx so I'm looking into making armor for us. Hence why I'm here.

 

And no the swords aren't sharp

With blunted weapons I would think that the most important part isn't the shell, but the padding underneath. So I'd probably go for an aluminum scale mail, or chainmail even, with an inch or better of padding. Another consideration for me would be the cost and availability of materials. Old road signs would be my go to material since I know where to get a stack of them for free.

Try slipping pool noodles over closet rods and wrapping in duct tape. We used pipe insulation. Foot ball pads and helmets are a start (and show up at Good will often) , if one really wants to make something their is an  indestructible on Chinese scale. It could be duplicated in cut up plastic drum for cheep. Shields from 1/2 ply are pretty close to weight for real ones, two layers of 1/4 laminated if you want a curved one like the Romans. 

All of those are lethal weapons unless padded, all of those could be withstood by barrel plastic armour with appropriate padding. T6 Al would be another choice.

The fancier heat treated steel or titanium are probably not needed where you are at now.  Please see armourarchive.org    !!!!!!!