1, titanium alloy
Titanium alloy is an alloy composed of titanium and other elements. Titanium has two kinds of homogeneous crystals: α-titanium with a close-packed hexagonal structure below 882 ° C, and β-titanium with a body-centered cube above 882 ° C. Alloying elements can be divided into three categories according to their influence on the phase transition temperature: ① The element that stabilizes the α phase and increases the phase transition temperature is the α stable element, which includes aluminum, carbon, oxygen, and nitrogen. Among them, aluminum is the main alloying element of titanium alloy, which has obvious effects on improving the normal temperature and high-temperature strength of the alloy, reducing the specific gravity, and increasing the elastic modulus. ② The element that stabilizes the β phase and reduces the phase transition temperature is the β stable element, and can be divided into two types: isomorphic and eutectoid. The former includes molybdenum, niobium, vanadium, etc .; the latter includes chromium, manganese, copper, iron, silicon, etc. ③ The elements that have little effect on the phase transition temperature are neutral elements, such as zirconium and tin.
2, aluminum alloy
Generic term for aluminum-based alloys. The main alloying elements are copper, silicon, magnesium, zinc, and manganese, and the minor alloying elements are nickel, iron, titanium, chromium, and lithium.
Aluminum alloy has low density, but high specific strength, close to or exceeding high-quality steel, good plasticity, can be processed into various profiles, has excellent electrical conductivity, thermal conductivity, and corrosion resistance, and is widely used in industry. Its usage is second only to steel .
There are two types of aluminum alloys: cast aluminum alloys, which are used in the as-cast state; deformed aluminum alloys, which can withstand pressure processing, have higher mechanical properties than the as-cast state. It can be processed into various shapes and specifications of aluminum alloy materials. Mainly used in the manufacture of aviation equipment, daily necessities, construction windows and doors.
Aluminum alloys can be divided into deformed aluminum alloys and cast aluminum alloys according to processing methods. Deformed aluminum alloys are divided into non-heat-treatment-reinforced aluminum alloys and heat-treatment-reinforced aluminum alloys. The non-heat-treatment-reinforced type cannot improve mechanical properties through heat treatment, and can only be strengthened through cold working deformation. It mainly includes high-purity aluminum, industrial high-purity aluminum, industrial pure aluminum, and rust-proof aluminum. Heat-treatment-reinforced aluminum alloys can be improved in mechanical properties through heat treatment methods such as quenching and aging. It can be divided into hard aluminum, wrought aluminum, super-hard aluminum, and special aluminum alloys.
Aluminum alloy can be heat treated to obtain good mechanical properties, physical properties and corrosion resistance.
According to chemical composition, cast aluminum alloy can be divided into aluminum-silicon alloy, aluminum-copper alloy, aluminum-magnesium alloy and aluminum-zinc alloy.
3, magnesium alloy
Alloys based on magnesium and other elements. Its characteristics are: low density (about 1.8g / cm3), high specific strength, large elastic modulus, good shock absorption, greater impact load capacity than aluminum alloy, and good resistance to organic and alkali corrosion. The main alloying elements are aluminum, zinc, manganese, cerium, hafnium, and a small amount of zirconium or cadmium. At present, the most widely used are magnesium aluminum alloys, followed by magnesium manganese alloys and magnesium zinc zirconium alloys. Mainly used in aviation, aerospace, transportation, chemical, rocket and other industrial sectors. According to the forming method, it is divided into two types: deformed magnesium alloy and cast magnesium alloy.
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