There is a good article in the latest issue of Professional Boatbuilder Magazine about designing with aluminum alloys and how cold working and heat treatment affect corrosion resistance. You need to register to get access.
By this statement it is assumed that the focus is on cracking mechanisms rather than general weight loss corrosion. The hardness limitations quoted in NACE MR0175, MR0103 and SP0472 paint a ready picture of the observed effects of material hardness on the likelihood of cracking in various environments.
Hardness doesn't usually affect wall loss.
Higher hardness metals are more resistant to erosion.
Specific cracking mechanisms are affected by high hardness values.