Thermal Expansion of 2 attached metals

[audilover]

Homework Statement

This is more of a concept that I am confused on.

IF there are 2 metals, one on top of the other, and they are attached to each other and attached to a wall, and the only thing different between the two metals is the thermal expansion. When heated will the metal curve down or upwards?

Homework Equations

The Attempt at a Solution

Assuming the metal with the higher thermal expansion is on top, I thought it would curve towards the smaller thermal expansion, which would be downwards.

 

[gneill]

Attached how? At fixed points or are the metals welded along their interface? Which metal is heated? What are the coefficients of expansion? Is the temperature near the melting point of one or both metals (will their be sag not related to thermal expansion/contraction)?