What process involves joining two dissimilar metals at a junction and applying heat?

The correct answer to the question regarding the process that involves joining two dissimilar metals at a junction and applying heat is friction welding.

Friction welding is a solid-state welding process that generates heat through mechanical friction between the two surfaces being joined. When two dissimilar metals are pressed together and rotated or moved relative to each other, the friction produces localized heat at the junction which softens the materials, allowing them to flow and fuse together without melting. This results in a strong joint that maintains many of the properties of both metals.

In contrast, thermoelectricity refers to the direct conversion of temperature differences into electric voltage, rather than a joining process. Electrolysis involves chemical reactions caused by electricity in a solution and does not pertain to the mechanical joining of metals. Galvanization is a process of applying a protective zinc coating to steel or iron to prevent rusting and does not involve joining metals through heat. Thus, friction welding is the appropriate answer for the joining of dissimilar metals through heat application.