A structural member comprising at least two aluminum alloy parts displaying different property balances, said at least two parts being welded and wherein one of said parts either is (i) selected from an aluminum alloy different from the other of said at least two parts and/or (ii) is selected from an initial temper different from the other of said at least two parts, and wherein at least one of said at least two parts has been pre-aged prior to being welded, and, wherein said structural member has undergone a post-welding thermal treatment conferring a final temper to each of said at least two parts. The parts are advantageously welded by friction stir welding. Another subject of the invention is a method for manufacturing a structural member.