Interaction between iron and copper at 770 C

I'm planning to anneal a structure containing mild steel and iron above the Curie point of iron (769 C). This is for the pole
structure of an experimental electric motor. I need to hold some iron wires in the end of a mild steel slotted shaft. I looked at using clips or retaining rings of various sorts, but the clearances are pretty tight. Then I got the idea of cutting sections of copper tubing, and pushing them over the end of the shaft like a collar. This would require minimal clearance to adjacent structures, but I am concerned that the copper might interact with the iron or steel during the annealing. The forces pushing the wire out of the slot would be minimal, but I'm concerned that the copper might try to alloy with the iron, perhaps breaking the wires. Or, it might try to alloy with the steel, breaking the copper collar.
Does either of these scenarios seem likely, or even plausible?
I haven't worked out the exact temperature profile, but just guessing I would say ramp up from 25 C to 770 C over an hour, dwell at 770 C for 15 minutes to 1 hour, then ramp down as slow as possible, perhaps 24 to 72 hours. If possible, it'll be in a reducing atmosphere. (I haven't checked with the pottery kiln people to see if they offer that service, but I believe some glazes require a reducing atmosphere, so I would think it is offered.)
If the copper collars weld themselves to the steel shafts, that would not be a problem as long as they don't break. I don't intend to take apart the assembly.
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