The main reason why metals be bent and formed is due to their unique atomic structure and chemical bond characteristics.
For example, plasticity and ductility are good explanations for the bending and forming of metals.
The plasticity of metals gives them good deformation ability. Plasticity is the ability of metal materials to undergo plastic deformation under the action of external forces. This is because the crystal structure of metals is composed of tightly packed metal atoms, and there are strong metal bonds between atoms. When external forces act on metal materials, the metal bonds between metal atoms will break or slip, causing the metal to undergo plastic deformation. This deformation can give metal materials a variety of different shapes, such as stretching, compression, bending, etc.
The ductility of metals enables them to undergo large deformations during stretching without breaking. Ductility is the ability of metal materials to undergo large deformations without breaking under the action of external forces. This is because metal materials have strong fracture toughness and can withstand a certain degree of tensile stress without breaking. When external forces act on metal materials, the metal grains will gradually slip and roll, causing the material to undergo ductile deformation. This ductility allows metals to be stretched into various shapes, and also gives them good impact resistance and toughness.
Changes in grain structure
The microstructure of metals is mainly composed of grains, and each grain is composed of a large number of atoms arranged in a regular manner. When the metal is subjected to tensile force, the atomic arrangement inside the grain will be relatively displaced, resulting in the deformation of the grain. At the same time, the interface between the grains will also be relatively displaced, a process called slip.
When the metal is subjected to external force, the atoms in the grain will slide along the lattice plane, thus forming the plastic deformation of the metal. When the external force continues to act, the atoms in the grain will continue to slip, eventually causing the deformation of the entire metal. It is worth noting that this plastic deformation is reversible, that is, the metal can still return to its original shape after the external force is removed.
The grain structure of the metal is also affected by the recrystallization of the grain. When the metal is subjected to a large deformation, dislocation will occur inside the grain, which will reduce the deformation ability of the grain. In order to restore the plasticity of the metal, the grains will reorganize through the recrystallization process to form a new grain structure, so that the metal can be restored to its original state.
Changes in the metal bonds between atoms
The microstructure of the metal is composed of a large number of densely arranged metal atoms. These metal atoms are connected to each other through metal bonds. Metal bonds are a chemical bond between metal atoms, characterized by the sharing of free electrons between metal atoms. This way of sharing electrons enables metal atoms to form various forms under external action, such as stretching, squeezing, bending, etc.
When the metal is stretched by external force, the atoms inside the metal begin to move. This is because the external force changes the metal bonds between metal atoms. Normally, the positions of metal atoms are relatively fixed, and they form a stable structure by sharing free electrons. However, when external force acts on the metal, the interaction between atoms changes, and the metal bonds are stretched or compressed, causing the shape of the metal to change.
During the stretching process of the metal, the metal bonds between metal atoms will gradually stretch, causing strain inside the metal. When the external force continues to increase, the metal bonds between metal atoms will reach a critical value and can no longer withstand greater tension. At this time, the metal will undergo plastic deformation, that is, the shape of the metal will change significantly. This plastic deformation of the metal is caused by the change of the metal bonds between atoms.
In addition to the stretching phenomenon of metals, deformations such as compression and bending of metals are also closely related to the change of metal bonds between atoms. The metal bond structures between atoms of different metals are different, which is one of the reasons why different metals exhibit different properties when subjected to force.
Effect of external force on grain orientation
The effect of external force on grain orientation is achieved through grain boundary slip and dislocation slip. In metal materials, grain boundaries are the bonding surfaces between adjacent grains, the atoms in the grain boundaries are arranged in order, and there is a certain angle between the grain boundaries of different grains. When external force acts on metal materials, it will cause the slip of grain boundaries, that is, the position of the grain boundaries between adjacent grains changes. At the same time, dislocations will also propagate in metal grains, and the relative movement between grains will be achieved through dislocation slip. The two slip mechanisms work together to cause metal materials to deform under external forces.
The influence of external forces on grain orientation is also reflected in the process of grain recrystallization. During the stretching process of metal materials, due to the increase in dislocation density inside the crystal, the strain difference between the grains increases, resulting in dislocation accumulation and creep at the grain boundaries. In this case, the grains will gradually lose their original orientation and recrystallization will occur. Recrystallization will cause the grains to grow again and rearrange the grain orientation, thereby changing the microstructure and properties of the metal material.
Intermolecular slip of metals
The molecular structure of metals is characterized by an ionic crystal structure composed of metal ions. In the crystal structure, metal atoms are bound to each other through metal bonds to form a fully dense structure. When external forces act on metals, the metal bonds between metal atoms will be affected by traction, and the metal atoms will be displaced, which is the plastic deformation of the metal. The intermolecular slip of metals is one of the important reasons for the plastic deformation of metals.
Intermolecular slip of metals refers to the process in which atoms or ions inside metals slide along the lattice plane under the action of external forces. There are multiple grain boundaries and dislocations in the crystal structure of metals, which are the main channels for atomic slip inside metals. When external force acts on metals, stress concentration will occur between the grains, and the dislocations inside the crystals will continue to increase, thereby promoting the mutual slip of atoms inside the metal. At this time, the mutual slip between metal molecules plays a vital role, allowing the metal to undergo plastic deformation.
The mutual slip between metal molecules not only occurs in the macroscopic metal stretching process, but also exists at the microscopic atomic scale. When metals are subjected to external forces, the atoms inside the grains will be displaced, and the grain boundaries between the grains will also slip relative to each other, thereby achieving the deformation of the metal. Moreover, the mutual slip between metal molecules can also reduce many mechanical properties of metals, such as strength and hardness. Therefore, in the process of metal processing, it is necessary to pay attention to controlling the mutual slip between metal molecules to ensure the quality and performance of metal products.
Of course, the bending and forming of metals are widely used in industry and art. In the industrial field, the ductility of metals enables them to undergo deformations such as stretching and extrusion, and is used in machinery manufacturing, construction, aerospace, shipbuilding and other fields. In the field of art, the ductility of metal provides endless possibilities for artistic creations such as sculpture.
For information about metal surface treatment processes and sheet metal fabrication services, feel free to contact Mulan Group Sheet Metal Fabrication, a leading sheet metal manufacturing service provider in China. We specialize in ODM/OEM metal processing and continuously update industry insights while delivering high-quality sheet metal services for your reference.
Here is our Metal Stamping sample Display：
