I would get a reinforced fiber wheel and use that.

Tenryu makes a good metal cutting blade as well.

thank you.

I frequently cut aluminum with a powered miter saw. Key is to use a carbide tipped blade and a good wax lubricant. The wax comes in a solid stick or tube (boelube is good) most home depots have this. Spin the saw up and press the wax on the blade, it will leave a coat of wax on the blade. Then as you cut, the wax will melt and lubricate the cutting surfaces. I'm usually cutting something more robust than screen frames. You'll need a fine tooth blade. Check a picture frame shop or site for picture frame materials. They use the same technique.

Good Advice lkbum.