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Metallic materials is a collective term for materials with metallic properties that are composed of metallic elements or predominantly metallic elements. It includes pure metals, alloys, intermetallic compounds and special metal materials.

The development of human civilization and social progress with the metal material is very close. Following the Stone Age after the emergence of the Copper Age, the Iron Age, are the application of metal materials as a significant sign of the era. In modern times, a wide variety of metal materials have become an important material basis for the development of human society. Our understanding of metal materials should start from the following aspects:

I. Classification:

Metal materials are usually divided into ferrous metals, non-ferrous metals and special metal materials.

① ferrous metals, also known as iron and steel materials, including industrial iron containing more than 90% of iron, carbon 2% to 4% of cast iron, carbon steel containing less than 2% of carbon, as well as a variety of uses of structural steel, stainless steel, heat-resistant steel, high-temperature alloys, precision alloys and so on. Broadly speaking, ferrous metals also include chromium, manganese and its alloys.

②Non-ferrous metals is in addition to iron, chromium, manganese, all metals and their alloys, usually divided into light metals, heavy metals, precious metals, semi-metals, rare metals and rare earth metals. Non-ferrous alloys of strength and hardness is generally higher than pure metal, and resistance, resistance temperature coefficient is small.

③Specialty metal materials include structural and functional metal materials for different purposes. Among them, there are amorphous metal materials obtained through rapid condensation process, as well as quasi-crystalline, microcrystalline, nanocrystalline metal materials, etc.; there are stealth, hydrogen resistance, superconductivity, shape memory, wear-resistant, vibration damping and other special functional alloys, as well as metal matrix composites, etc..

Metal materials according to the production of molding process is divided into casting metals, metal deformation, spray molding metals, and powder metallurgy materials.

Cast metal molding process through casting, mainly cast steel, cast iron and cast non-ferrous metals and alloys.

Transformation of metal molding through pressure processes such as forging, rolling, stamping, etc., its chemical composition is slightly different from the corresponding casting metal.

Injection molding metal is made through the injection molding process with a certain shape and organizational properties of the parts and blanks.

The properties of metal materials can be divided into process performance and use of two kinds of performance.

Two, performance

For more rational use of metal materials, give full play to its role, we must master a variety of metal materials made of zero, components in the normal operating conditions should have the performance (performance) and its hot and cold machining process should have the performance of the material (process performance).

The use of materials, including physical properties (such as specific gravity, melting point, electrical conductivity, thermal conductivity, thermal expansion, magnetism, etc.), chemical properties (durability and corrosion, oxidation resistance), mechanical properties, also known as mechanical properties.

The process properties of the material refers to the ability of the material to adapt to cold and hot processing methods.

Three, the production process:

Metal materials production, generally the first extraction and smelting of metal .

Some metals need to be further refined and adjusted to the appropriate composition, and then processed into a variety of specifications and properties of the product. Refining metal, iron and steel are usually pyrometallurgical process, that is, the use of converters, flat furnaces, electric arc furnaces, induction furnaces, cupolas (iron smelting) and other smelting and melting; non-ferrous metals both pyrometallurgical and hydrometallurgical process; high purity metals and metals requiring special properties are also used in the area of melting, vacuum melting and powder metallurgy process. Metallic materials through smelting and adjust the composition, after casting molding, or casting, powder metallurgy molding process into ingots, billets, and then by plastic processing into a variety of forms and specifications of the product. For some metal products, the requirements of its specific internal organization and mechanical properties, but also often use the heat treatment process. Commonly used heat treatment processes are quenching, normalizing, annealing, aging treatment (the quenched metal parts placed at room temperature or higher temperature insulation for an appropriate period of time, in order to improve its strength and hardness) and so on.

Four, the development trend:

The development of metal materials has been from pure metal, pure alloys to get rid of. With the material design, process technology and the use of performance testing progress, the traditional metal materials have been rapidly developed, new high-performance metal materials continue to be developed. Such as rapid condensation amorphous and microcrystalline materials, high specific strength and high specific mode of aluminum-lithium alloys, ordered intermetallic compounds and mechanical alloying alloys, oxide dispersion strengthened alloys, directional solidification of columnar crystal and single-crystal alloys and other high-temperature structural materials, metal-based composites, as well as shape memory alloys, neodymium-iron-boron permanent magnet alloys, hydrogen storage alloys, and other new functional metal materials, respectively, have been in the aerospace, energy, electromechanical and other fields They have been applied in various fields such as aerospace, energy, electromechanical and so on, and have produced great economic benefits.