Surely if you're at University studying about materials, then we should be the ones asking you!

I've made such caliper brackets from Al 5052, 5083, 6061 and 7075.

The 5052 bent, the 5083 and 6061 were great and the 7075 cracked.

As for oxidising, well why not anodize it? 6061 looks great when anodised. I could only ever get 5000 series ali to anodise grey, and the 7000 came out sort of yellowy. My anodizing technique is very crude!

I know of others that use Al 2017 for various brackets so that may be worth looking into. Never used it by choice though other than when I was in Japan.

Many companies use Al 6061 T6 for many applications in the bike world, from sprockets to caliper brackets, so that'd be my first consideration.