kovettumislaki

Kovettumislaki, meaning "hardening law" in Finnish, is a material science concept describing the phenomenon where a material's resistance to plastic deformation increases as it is deformed. This effect is commonly observed in metals and other ductile materials. When a material undergoes plastic deformation, its crystalline structure changes. Dislocations, which are line defects in the crystal lattice that allow for plastic flow, interact with each other and with other microstructural features. These interactions create obstacles to dislocation movement, making it more difficult for further plastic deformation to occur. Consequently, the stress required to continue deforming the material rises.

This increased resistance to deformation is often represented by a stress-strain curve, where the stress continues to increase after the yield point has been passed. The rate at which this hardening occurs is material-dependent and influenced by factors such as temperature, strain rate, and the initial microstructure. Understanding kovettumislaki is crucial in various engineering applications, including metal forming processes like rolling, forging, and drawing, as it dictates the forces required and the final properties of the manufactured parts. It also plays a role in the performance of components subjected to cyclic loading, such as in fatigue analysis.