Why yes! They can!!!I'm learning some different methods of marrying layers of metal to make patterns!!
The one below is called multi-metal lamination. It's a type of faux married metal. This is done by cutting strips of silver, brass and copper and melting solder between them. I put the stack through a rolling mill and slice off layers with my saw, then put the striped slices side by side and solder them until I make it as wide as I need it. The result is multi stripes of color.
There are Many different ways to do this.
ganskin has a nice article on it if you care to learn more. www.ganoskin.com/bori sat/Neman/metal-overlay.htm
or ask me about it and I'll be happy to share more detailed instructions with you :)