RCU Forums - Bending loads on aluminum tubes
6061-T6 is a good general purpose aluminum alloy, particularly if welding is required, but I would try to find a piece of 2024 or 7075. 6061 has a yield strength of about 40,000 PSI, versus about 70,000 for 2024-T3, and 7075 is stronger still, but hard to find.