If the damage is at the bottom portion of the mast, then you could think about sleeving it internally without affecting the bend characteristics. Just find a length of the same mast section about a couple of feet long. Grind off the luff track and the flat web that forms the wall of the track plus a bit more. You now have a U-shaped piece of extrusion. Fit this inside the mast and then pop rivet it in place using about a dozen aluminium rivets. You might want to get a new mast anyway, but if you sleeve your old one, you'll have a good spare.