I haven't had much luck in searching on how sheet metal can made. In
particular I want to make small sample sheets with a few layers of
metals or alloys. I know this can be done, because for example some
coins are made from 3 metal layers described as 'fused' or bonded
together.

Anyone have any idea or know any books on this subject of metals fusing
(not being alloyed, but just physically bonded together) together?
-Joe