I had a materials science course as part of my ME undergrad. (And of course there was overlap in other courses.)

When I went to grad school for a Master's at an engineering school which, at the time, was small enough to not actually have formal departments, I studied a fair bit of mechanical engineering but actually did a materials science thesis.

In Sweden, at many places that do a materials science engineering degree, it is historically under "Mining engineering" rather than "machine engineering".

True! Even my diploma in ME course has a subset of MatSci in it. Fascinating stuff.