Low density, high specific strength The density of tita […]
Low density, high specific strength
The density of titanium metal is 4.51g/cm3, which is higher than High Purity Titanium and lower than steel, copper, and nickel, but its specific strength is the first among metals.
Titanium is a very active metal, its equilibrium potential is very low, and the thermodynamic corrosion tendency in the medium is high. But in fact, titanium is very stable in many media. For example, titanium is corrosion-resistant in oxidizing, neutral and weakly reducing media. This is because titanium and oxygen have a great affinity. In the air or in an oxygen-containing medium, a dense, strong adhesion and inert oxide film is formed on the surface of titanium, which protects the titanium matrix from corrosion. Even due to mechanical wear, it will quickly heal itself or regenerate. This indicates that titanium is a metal with a strong tendency to passivation. The titanium oxide film always maintains this characteristic when the medium temperature is below 315℃.
In order to improve the corrosion resistance of titanium, surface treatment technologies such as oxidation, electroplating, plasma spraying, ion nitriding, ion implantation, and laser treatment have been developed to enhance the protection of the titanium oxide film and obtain the desired corrosion resistance. effect. In response to the need for metal materials in the production of sulfuric acid, hydrochloric acid, methylamine solution, high-temperature wet chlorine and high-temperature chloride, a series of corrosion-resistant titanium alloys such as titanium-molybdenum, titanium-palladium, titanium-molybdenum-nickel, etc. have been developed. Titanium castings use titanium-32 molybdenum alloy, titanium-0.3 molybdenum-0.8 nickel alloy is used in environments where crevice corrosion or pitting corrosion is common, or titanium-0.2 palladium alloy is used locally in titanium equipment, and they are all well used. effect.
Good heat resistance
The new titanium alloy can be used for a long time at 600°C or higher.
Good low temperature resistance
Low temperature titanium alloy represented by titanium alloy TA7 (Ti-5Al-2.5Sn), TC4 (Ti-6Al-4V) and Ti-2.5Zr-1.5Mo, etc., whose strength increases with decreasing temperature, but does not change plasticity. Big. It maintains good ductility and toughness at low temperatures of -196-253°C, avoids cold brittleness of metals, and is an ideal material for cryogenic containers, storage boxes and other equipment.
Strong resistance to damping
After being subjected to mechanical and electrical vibrations, titanium has the longest vibration decay time compared with steel and copper. This performance of titanium can be used as a tuning fork, medical ultrasonic pulverizer vibrating element and high-end acoustic speaker vibrating film.
Titanium is a non-magnetic metal and will not be magnetized in a large magnetic field. It is non-toxic and has good compatibility with human tissues and blood, so it is adopted by the medical profession.
The tensile strength is close to its yield strength
This performance of titanium shows that its yield ratio (tensile strength/yield strength) is high, which means that the plastic deformation of metal titanium materials is poor during forming. Due to the large ratio of the yield limit of titanium to the modulus of elasticity, the resilience of titanium during molding is large.
Good heat transfer performance
Although the thermal conductivity of metallic titanium is lower than that of carbon steel and copper, due to the excellent corrosion resistance of titanium, the wall thickness can be greatly reduced, and the heat exchange method between the surface and the steam is dropwise condensation, which reduces the heat group. Without scaling, the thermal resistance can be reduced, and the heat transfer performance of titanium can be significantly improved.
Low modulus of elasticity
The elastic modulus of titanium is 106.4GPa at room temperature, which is 57% of steel.
Titanium is a chemically very active metal, which can react with many elements and compounds at high temperatures. Titanium getter mainly refers to the reaction with carbon, hydrogen, nitrogen, and oxygen at high temperatures.