Munkahardítást

Munkahardítást is a Hungarian term that translates to "work hardening" or "strain hardening" in English. It is a metallurgical phenomenon that occurs in ductile metals when they are plastically deformed. This deformation can be caused by processes such as rolling, drawing, forging, or stretching.

When a metal undergoes plastic deformation, its internal crystal structure, known as the lattice, becomes distorted. Dislocations, which are line defects within the crystal lattice, move and interact with each other. As more deformation occurs, the density of dislocations increases. These dislocations then impede the movement of other dislocations, making it more difficult for further plastic deformation to occur.

This increased resistance to deformation manifests as a significant increase in the metal's yield strength, tensile strength, and hardness. Conversely, the ductility and electrical conductivity of the metal typically decrease. The extent of work hardening depends on the type of metal, the amount of deformation it undergoes, and the temperature at which the deformation occurs.

Work hardening is often a desirable effect in manufacturing. For example, it is used to strengthen wires, sheets, and other metal components without the need for heat treatment. However, if excessive work hardening occurs, the metal may become too brittle and prone to fracture. In such cases, annealing, a heat treatment process, can be used to reverse the effects of work hardening and restore ductility.