Explanation

dislocation slip can cause shear deformation of crystals, which is the main mechanism of metal plastic deformation. dislocation causes the dislocation of atoms in the crystal, and then causes the elasticity distortion of the lattice structure of the nearby crystal, so dislocation is also the source of internal stress. Only when the stacking fault energy of the metal is very low, the decomposition of complete dislocation will appear obviously. When certain conditions are met, complete dislocation can be decomposed into several parts of dislocation, but it must be satisfied that the energy before decomposition is greater than the total energy of each part after decomposition. Only such decomposition is advantageous from the perspective of energy, so this process can proceed on thermodynamics. Therefore, it can be considered that there is a certain repulsive effect between the dislocations in various parts. When the complete dislocation decomposes on a crystal plane, the normal lattice structure between the dislocation on the crystal plane is further destroyed, which promotes the energy increase of the system. This energy is called stacking fault energy.

Classification