Heck, they still make airplanes out of aluminum. If the stuff can withstand the stress of flying, I would imagine it can survive the stress of being used in a frame lock folding knife (assuming it's quality aluminum and properly heat-treated).
Reminds me of the old debate over aluminum 1911 frames versus steel frames. I remember when I was against aluminum frames, then I discovered a guy who worked at the gun store I frequented carried an aluminum frame 4" 1911. He knew a lot about guns, and he could have carried any pistol he wanted. He told me that he had put thousands of rounds through his pistol without issues. Since it was the gun he chose to defend his life at work I was inclined to believe him. Of course he only ran ball ammo through it. But .45 ball ammo is still plenty lethal.
A quality knife is a quality knife, whatever it's made of. The only way to know how an aluminum frame lock knife performs is to use it and find out.