 Grain boundary strengthening

Grain boundary strengthening, also known as grain boundary hardening or Hall-Petch strengthening, is a mechanism that enhances the strength and hardness of polycrystalline materials by reducing the average size of the grains in the material. It operates on the principle that smaller grain sizes impede the movement of dislocations, which are structural defects in the crystal lattice that play a significant role in plastic deformation. ### Key Concepts: 1. **Grain Boundaries**: These are interfaces where crystals of different orientations meet.