Metal materials include pure metals, alloys, intermetallic compounds and special metal materials.
The development of human civilization and the progress of society are closely related to metal materials. Following the Stone Age, the bronze age and the iron age are marked by the application of metal materials. Modern, a wide variety of metal materials have become an important material basis for the development of human society.
Types of 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, include industrial pure iron containing more than 90% iron, cast iron containing 2%-4% carbon, carbon steel containing less than 2% carbon, and structural steel, stainless steel, heat-resistant steel, high-temperature alloy, precision alloy for various purposes. The generalized ferrous metals also include chromium, manganese and their alloys.
(2) Non-ferrous metals refer to all metals and their alloys except iron, chromium, and manganese, which are usually divided into light metals, heavy metals, precious metals, semi-metals, rare metals and rare earth metals. The strength and hardness of nonferrous alloys are generally higher than those of pure metals, and the resistance is large and the resistance temperature coefficient is small.
(3) Special metal materials include structural metallic materials and functional metallic materials for different purposes. Among them are amorphous metal materials obtained by rapid condensation, quasicrystal, microcrystalline, nanocrystalline metal materials, and other special functional alloys such as stealth, hydrogen resistance, superconductivity, shape memory, wear resistance, vibration damping and metal matrix composites.
1. Metal
Metals are materials with gloss, good conductivity, thermal conductivity, good mechanical properties, and positive temperature resistance coefficient. It can be divided into two categories: black metal and non-ferrous metal.
Ferrous metals mainly refer to iron, manganese, chromium and their alloys, such as steel, pig iron, ferroalloy, etc.
Nonferrous metals mainly refer to metallic elements (a total of 79 species) and their alloys except black metals. The pure metals of nonferrous metals can be divided into light nonferrous metals, heavy nonferrous metals, precious metals and rare metals.
2. Alloy
An alloy is a material with metallic properties composed of two or more metallic elements, or both metallic and non-metallic elements.
3. Light nonferrous metals
Light non-ferrous metals refer to the proportion of non-ferrous metals below 4.5, they are: aluminum, magnesium, sodium, potassium, calcium, strontium, barium, its common characteristics are small proportion (0.53-4.5), chemical activity.
4. Heavy nonferrous metals
Heavy non-ferrous metals refer to non-ferrous metals with a specific gravity of more than 4.5, including copper, nickel, lead, zinc, cobalt, tin, antimony, mercury, cadmium, bismuth and so on.
5, precious metals
Precious metals refer to gold, silver and platinum group elements. Precious metals are characterized by their high specific gravity (10.4-22.4), high melting point (916-3000℃), stable chemical properties, acid and alkali resistance, and corrosion resistance.
6, half metal
Semi metals refer to 9 elements, such as silicon, germanium, selenium, tellurium, arsenic and boron. Its physical and chemical properties are between metals and nonmetals.
7. Rare and light metals
Rare light metals refer to five kinds of metals: lithium, beryllium, rubidium, cesium, and titanium. Their common point is the small proportion.
8. Rare high melting point metals
The rare high melting point metals refer to 8 metals: tungsten, molybdenum, tantalum, niobium, zirconium, hafnium, vanadium and rhenium. They have high melting point, high hardness, strong corrosion resistance, and can form very hard and very refractory stable compounds with some non-metallic.
9. Rare dispersed metals
Rare and dispersed metals are also called scattered metals. They are four kinds of metals, gallium, indium, thallium and germanium.
10. Rare earth metals
Rare earth metals include lanthanides and 17 metals with similar properties to lanthanides: scandium, yttrium, lanthanum, cerium, praseodymium, niobium, columbium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, lutetium and lutetium.
11. Rare radioactive metals
Rare radioactive metals refer to natural radioactive elements, such as polonium, radium, actinide, thorium, uranium and uranium.
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