The basic concept of metal plastic deformation

The basic concept of plastic deformation of metal Under the action of external force, the change of shape and size of metal is called deformation, which is divided into elastic deformation and plastic deformation. 1.1.1 The physical concept of plastic deformation All solid metals are crystals, and atoms are arranged in an orderly manner in the space occupied by the crystals. When there is no external force, the atoms in the metal are in a stable equilibrium state, and the metal object has its own shape and size. The application of external force will destroy the original equilibrium state between atoms, cause atomic row distortion, and cause changes in the shape and size of the metal. 1.1.1 Crystal deformation a) no deformation b) elastic deformation c) elastic deformation + plastic deformation d) plastic deformation, if the external force is removed, the atoms in the metal immediately return to the original stable and balanced position, the atomic arrangement distortion disappears and the metal completely recovers itself The original shape and size, such deformation is called elastic deformation. Increasing the external force will increase the degree of distortion of the atomic arrangement, and the moving distance may be greater than the distance between the atoms before the force is applied. At this time, a part of the atoms in the crystal will have a larger misalignment with respect to the other part. After the external force is removed, although the distance between the atoms can still be restored to its original state, the misaligned atoms cannot return to their original positions, and the shape and size of the metal have also undergone permanent changes. This irreversible permanent deformation under the action of external force is called plastic deformation. When subjected to external forces, atoms always move away from the equilibrium position. Therefore, under the condition of plastic deformation, the total deformation includes both plastic deformation and elastic deformation that disappears after the external force is removed. Previous post: English-Chinese comparison of standard spare parts commonly used in metal stamping dies