What are the ways to strengthen metal? and its applications

<>1. Solution strengthening: The solute atoms integrated into the solid solution cause lattice distortion, which increases the resistance of dislocation motion and makes it difficult to slip, so that the strength and hardness of the alloy solid solution increase.

2. Fine grain strengthening: refers to the method of improving the mechanical properties of metal materials by refining the grains, and the industry will improve the strength of the materials by refining the grains.

3. Dislocation strengthening: It is one of the most effective strengthening methods in metal materials. In metals that are prone to cross-slip, the dislocations will be arranged into three-dimensional substructures after the strain exceeds a certain level, and when the dislocation walls of these substructures are loosely tangled, they are called"Cellular structure"。

4. Work hardening: the phenomenon that the strength and hardness of metal materials increase when they are plastically deformed below the recrystallization temperature, while the plasticity and toughness decrease.

5. Second phase strengthening: It means that when the second phase is evenly distributed in the matrix phase with fine and diffuse particles, it will have a significant strengthening effect.

6. Diffusion strengthening: refers to a means of strengthening a material by adding hard particles to a homogeneous material.

Primary reinforcer: directly (indirectly) related to human physiological needs, such as food, opportunity, etc., also known as "primary primordial reinforcer" or "physiological reinforcer".

Secondary reinforcer: Food that becomes a signal for a primary reinforcer, also known as a "secondary reinforcer". It is learned under certain conditions because they have a reinforcing effect on the person with the recurrence of primary reinforcers.

Secondary reinforcement classification:

Social reinforcer: encouragement, praise language, expressions and actions (such as praise, smile, kiss) Activity reinforcer: interrupt learning and play favorite games, such as listening**;

Symbolic reinforcements: scores, safflowers, tokens, etc.

Intrinsic reinforcers: pride, a sense of accomplishment after completing a task, etc.

1. Aging strengthening: It refers to the precipitation of alloying elements in high temperature in some form under normal temperature or heating conditions after the solid solution of alloying elements, forming diffusely distributed hard points, causing resistance to dislocation cutting, increasing strength and reducing toughness.

2. Solution strengthening: the presence of alloying elements in the matrix metal lattice causes the crystal lattice to be distorted, and the dislocation movement resistance increases. Usually the strength also increases and the toughness decreases.

3. Fine grain strengthening is also called grain boundary strengthening: finer grains can be obtained through deformation and recrystallization, so that the strength and toughness can be improved at the same time.

4. Deformation strengthening: With the increase of plastic deformation, the rheological strength of the metal also increases, which is called deformation strengthening or work hardening.

5. Diffusion strengthening: The method of strengthening the material through the distribution of fine diffuse second-phase fine particles in the matrix is called diffusion strengthening.

6. Fiber strengthening: The method of strengthening the matrix material by combining high-strength fibers with appropriate matrix materials is called fiber strengthening.

7. Irradiation strengthening: Because the metal produces vacancies or gap-filling atoms under strong ray conditions, the defects hinder the movement of dislocations, thus producing a strengthening effect.

The commonly used strengthening methods for metal materials include fine grain strengthening, solid solution strengthening, second-phase strengthening, and work hardening.

1 Fine-grained strengthening.

The method of improving the mechanical properties of metal materials by refining the grains is called fine grain strengthening, and the strength of the material will be improved by refining the grains in the industry.

The principle is that usually metals are polycrystals composed of many grains, and the size of the grains can be expressed in terms of the number of grains per unit volume, and the more the number, the finer the grains.

2. Solution strengthening.

The phenomenon that the alloying elements are solidly dissolved in the matrix metal, causing a certain degree of lattice distortion and thus increasing the strength of the alloy.

Principle: The solute atoms integrated into the solid solution cause lattice distortion, which increases the resistance of dislocation motion and makes the slip difficult, so that the strength and hardness of the alloy solid solution increase.

3. Second phase reinforcement.

Compared with single-phase alloys, in addition to the matrix phase, there is a second phase in addition to the matrix phase. When the second phase is evenly distributed in the matrix phase with fine dispersed particles, it will have a significant strengthening effect.

Principle: The interaction between them and the dislocation hinders the movement of the dislocation and improves the deformation resistance of the alloy. For the motion of dislocations, the second phase contained in the alloy has the following two cases:

1. Strengthening effect of non-deformable particles.

2. Strengthening of deformable particles. Both diffusion enhancement and precipitation enhancement belong to the special cases of second-phase enhancement.

Fourth, work hardening.

With the increase of cold deformation, the strength and hardness indexes of metal materials have improved, but the plasticity and toughness have decreased.

Principle: When the metal is plastically deformed, the grain slips, and the dislocation of the entanglement appears, which makes the grain elongated, broken and fibrous, and the residual stress is generated inside the metal.