How does annealing impact metal properties?

Annealing is a heat treatment process that involves heating a metal to a specific temperature and then allowing it to cool slowly. This process significantly affects the metal's microstructure, which in turn alters its physical properties. The correct answer highlights that annealing softens the metal, making it easier to work with.

When metals are subjected to annealing, the atomic structure is allowed to rearrange, which reduces internal stresses and dislocations that may have formed during prior processing. This reduction in dislocations enables the metal to become more ductile. A more ductile metal can be easily shaped or formed, enhancing its workability. This is especially beneficial in manufacturing processes where shaping and forming are required, as it minimizes the energy needed for these processes and reduces the risk of cracking or failure.

In contrast, other options would suggest effects that are not characteristic of annealing. Hardening typically involves processes that increase strength at the expense of workability, while increasing brittleness is counterproductive since it makes the metal less flexible and more prone to fracture. Retaining the initial properties suggests no significant alteration, which contradicts the very purpose of annealing, which is to modify the metal's properties for better performance during subsequent processing or use.