On Monday, 21 September 2020 22:35:41 UTC+1, newshound wrote:
I have some (relatively cheap) stainless steel saucepans that have a
separate "skin" in contact with the hob that is attached to the base of
the main deep pressed stainless steel body by what appears to be some
sort of crude alloy "braze". It does not look to be copper based. One of
these skins has come off. Does anyone have ideas as to what the now
exposed material might contain? Because of Covid I don't have access to
my normal pool of tame (and very smart) metallurgists with their
EDAX-SEM as a last resort.

If I have understood your description properly, it is very likely to be an aluminium alloy. Possibly with another layer sandwiching it.