An expanded laminate and method of forming an expanded laminate are disclosed. In at least one embodiment, the method includes selectively applying a relatively high temperature-resistant material to a surface of a first metal sheet to form a covered portion and an uncovered portion and diffusion bonding the first metal sheet to a second metal sheet at the uncovered portion to form a bonded region and an unbonded region. Pressurized gas may be introduced between the first and second metal sheets to expand the first and second metal sheets in the unbonded region. The metal sheets may be aluminum sheets. The sheets may be positioned in a die having a plurality of cavities such that when the pressurized gas is introduced the sheets expand into the cavities. The diffusion bonding may be performed by applying pressure, for example, using rollers.