What is the effect of controlled cooling (annealing) on materials processed?

Controlled cooling, often referred to as annealing, is a heat treatment process used to alter the physical and sometimes chemical properties of materials. This process involves heating a material to a specific temperature and then allowing it to cool down slowly. The primary effect of this controlled cooling is the enhancement of ductility and strength.

During annealing, the structure of the material is modified. Specifically, it allows for the rearrangement of dislocations and promotes the growth of larger, more uniform grains within the metal or material. As a result, the material becomes less brittle and more ductile, meaning it can deform more readily without fracturing. Additionally, the strength of the material often increases as the internal stresses are relieved.

This process contrasts with rapid cooling techniques, which can lead to increased brittleness due to the formation of hard, brittle microstructures. Thus, the enhancement of ductility and strength is a fundamental outcome of controlled cooling, making this particular choice the correct answer.