Which of the following describes how deformed metals behave?

Deformed metals indeed lose their original shape permanently, which is a significant characteristic of plastic deformation. When a metal is subjected to stress beyond its yield strength, it undergoes a change in shape that does not reverse when the stress is removed. This change occurs because the internal structure of the metal, specifically the arrangement of its atoms, is altered in a way that creates dislocations or other defects. As a result, the metal takes on a new shape that is maintained even after the force is removed.

In contrast, retaining an original shape or reverting to it suggests elastic behavior, which is typically observed only up to a certain limit of stress. Metals that become brittle do so under certain conditions, such as low temperatures or specific alloying elements, rather than as a general behavior of all deformed metals. Thus, while some deformed metals may show increased brittleness, the defining feature is their permanent shape change due to plastic deformation.