@ the original poster:
One can also have a steel pin in steel fittings, attached to aluminum spars.
Google something like 'Corsair wing fold mechanism'. I'm not sure but there seems to be just a main spar pin to take mainly bending forces (rotating around a top one, pinned at the bottom), and some mechanism near the leading edge to take torque forces.
Bigger faster aircraft may use a bunch of pins. (Newer ones will also be certified under 'fail safe' rules requiring more damage tolerance, designs where even for the wing in general, there isn't just 1 critical spar, but a bunch of spar webs in the wing.)