Ten major properties of titanium:
1. The density is small, higher than the strength
The density of metal titanium is 4.51g/cm3, which is higher than aluminum and lower than steel, copper and nickel, but the strength is at the head of the metal.
2. Corrosion resistance
Titanium is a very active metal, its equilibrium potential is very low, and the thermodynamic corrosion in the medium tends to be greater. But in fact, titanium is stable in many media. For example, titanium is corrosion-resistant in oxidation, neutral and weak reducing media. This is because titanium and oxygen have a great affinity. In air or oxygen-containing media, a dense layer is formed on the titanium surface, with strong adhesion, and an inert oxide film protects the titanium matrix from corrosion. Even if the mechanical wear and tear will soon heal itself or regenerate. This indicates that titanium is a metal with a strong tendency to passivation. A titanium oxide film with a dielectric film temperature below 315°C always maintains this characteristic.
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 studied to enhance the protection of the titanium oxide film and obtain the ideal corrosion resistance effect. Developed a series of titanium-resistant titanium alloys, such as titanium-molybdenum, titanium-palladium, titanium-molybdenum-nickel, etc., for the production of sulfuric acid, hydrochloric acid, methylamine solutions, high-temperature wet chlorine and high-temperature metal chlorides. Titanium castings using titanium-32 molybdenum alloys often have crevice corrosion or pitting corrosion. When using titanium-0.3 molybdenum-0.8 nickel alloy or titanium equipment in an environment where titanium-0.3 molybdenum-0.8 nickel alloy or titanium equipment is used, titanium-0.2 palladium alloy is used locally, and the effect is very good.
3. Good heat resistance
The new titanium alloy can be used for a long time at 600°C or higher.
Four, low temperature performance
Titanium alloy TA7 (Ti-5Al-2.5Sn), TC4 (Ti-6Al-4V) and Ti-2.5Zr-1.5Mo are representative of low-temperature titanium alloys. The strength decreases with temperature, but the plastic change is not as large as -196- It maintains good ductility and toughness at a low temperature of 253℃, avoids cold brittleness of metals, and is an ideal material for low-temperature containers, tanks and other equipment.
Five, anti-damping performance
Metal titanium has the longest decay time compared with steel and copper through mechanical vibration, electric vibration and steel and copper. The use of titanium for this performance can be used as a tuning fork, a vibrating element of a medical ultrasonic crusher and a high-end audio speaker such as a diaphragm.
Six, non-magnetic, non-toxic
Titanium is a non-magnetic metal, it will not be magnetized in a large magnetic field, is non-toxic, and has good compatibility with human tissues and blood, so it is in the medical field.
Seven, the tensile strength and yield strength are close
This performance of titanium indicates that its yield ratio (tensile strength/yield strength) is high, indicating that the metallic titanium material is poor in plastic deformation during forming. Due to the large ratio of the yield limit of titanium to the modulus of elasticity, the shaping ability of titanium is elastic.
8. 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. The heat transfer method of the surface and steam is droplet condensation, thereby reducing the heat group and the surface is not condensed. Fouling can also reduce thermal resistance and significantly improve the heat transfer performance of titanium.
Nine, low elastic modulus
The elastic modulus of titanium is 106.4GMPa at room temperature and 57% for steel.
10. Inspiratory performance
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.
