@fallow valley 's idea, but in reverse, basically a normal metal, but also not rly. It'd be a material that changes durability drastically in a realistic temperature range, without actually melting.
It's durability being very low in hot areas, like near fire or in hot biomes, so it gets down to like 30 or something. And if you use it a few times, and get it down to let's say 25, it'll just be like that.
Untill you cool it, get it's max durability to like 300, and then realize, that the damage is... permanent so to speak. Or that it's greatness is. Because now the tool has 250 out of 300. It scales.
This is just an example, but shows it quite well i think.