Which of the following processes can improve ductility in materials?

Annealing is a heat treatment process that involves heating a material to a specific temperature and then allowing it to cool slowly. This process is primarily used to improve ductility and reduce hardness in metals. During annealing, the material's microstructure is altered; dislocations in the crystalline structure are reduced, allowing the metal to become more malleable.

By relieving stresses and promoting the growth of larger grains, annealing enhances the material's ability to deform plastically without fracturing. This makes the material more ductile, which is desirable in many applications where flexibility and shaping are necessary.

In contrast, processes such as quenching, hardening, and carburizing typically aim to increase strength and hardness rather than ductility. Quenching involves rapidly cooling a material, which can result in increased brittleness. Hardening techniques often emphasize creating a harder microstructure that can decrease ductility. Carburizing is a surface hardening process that introduces carbon into the surface layers of steel to improve wear resistance but does not inherently enhance ductility.