I would think the plastically deformed Al case was work hardened, and like a bent aluminum clutch/brake lever, will break if bent straight if it is not annealed first. Much easier to heat a lever and straighten than a hole in the case. It seems to me that the annealing temperature of brake levers is very close to the melting point as I have melted a couple while attempting to straighten them. Now that I look up annealing Al I see that there is a time at temperature element of .5 to 3 hours. Not knowing the actual temperature of the lever, I have probably gone well beyond the annealing temp thinking I needed a higher temperature when I needed more time. 600F to anneal vs. 1200F to melt, give or take. Having learned something, I can call this a good day, thx.
https://llfurnace.com/blog/types-of-...at-treatments/