Titanium in Aeronautical Field Abstract
Titanium, as a new metal, is widely used, especially in the field of aviation. It is even directly known as "space metal" . Titanium has been widely used in the manufacture of aeronautical equipment such as jet engines, missiles and spacecraft. So why on earth can this material have so many applications in the aviation field?
Titanium, as a new metal, has great prospects for development, and its application is gradually expanding, especially in the field of aviation. Titanium has been widely used in the manufacture of aeronautical equipment such as jet engines, missiles and spacecraft . According to statistics, the output of titanium is about two-thirds .
It is used in the manufacture of spacecraft engines and frameworks . So, what are the excellent properties of this metal, which makes it have in the field of aviation?
So many applications? The following article will answer this question. A kind of Reasons for Titanium Metal Widely Used in Aeronautical Field.
1. Light weight
Titanium density is 4.54g/cm3, while iron is 7.86g/cm3 ,Copper is 8.96g/cm3, aluminium is 2.7g/cm3 . Obviously, titanium is a relatively low density metal in these commonly used metals. It is well known that the smaller the density of materials used in the aviation industry, the better the other properties are guaranteed. Titanium meets this requirement very well. Therefore, titanium is widely used in aviation.
2. High hardness, strength and specific strength
Titanium has considerable hardness , and its Mohr hardness is 6 . Commercial grade titanium (99.2%) possesses ultimate tensile strength of about 434 MPa, twice that of common 6061-T6 aluminium alloy and five times that of magnesium, which is almost the same as low grade steel , while some titanium alloys have tensile strength of 1400 MPa . Because of its low density, its specific strength is quite high. For example, the density of titanium is only 55% of steel and 60% higher than that of aluminium, so the specific strength of titanium is 1.82 times of that of low grade steel and 1.25 times of that of 6061-T6 aluminium. In fact, titanium has the highest specific strength of all metals. And impurities in titanium, especially interstitial impurities such as oxygen, nitrogen and carbon, can greatly increase its strength , and such low density but high strength materials are the most popular in the aviation field, so titanium and its alloys are very popular in this industry.
3. Good plasticity
The higher the purity of titanium, the better the plasticity. The elongation and section shrinkage of high purity titanium can reach 50-60% and 70-80%. Titanium has good ductility, especially in anaerobic environment . It is a metal material with excellent plasticity and ductility. This is conducive to its processing, forming and manufacturing. As we all know, the aviation industry has a great demand for metal materials, and also requires high productivity parts. In this case, the use of titanium and titanium alloys as aviation components is undoubtedly a good choice, and its wide application in this field is not surprising.
4. Good heat resistance
The melting point of titanium is astonishing over 1649 C , so there are few other materials that can match it in heat resistance. In flight, rockets, space shuttles and missiles will produce extremely high heat due to severe friction with the air, which will lead to the rapid increase of the shell temperature and finally reach a fairly high value. At this time, if the melting point of the shell material is not high enough, it will become soft, melt, or even melt, so the material needs to have very good heat resistance. The melting point of titanium is enough to withstand such temperature, and its heat resistance fully meets the requirements, so it is widely used in the manufacture of aerospace equipment shell.
5. Low temperature resistance
Low temperature titanium alloys, such as Ti-5Al-2.5Sn, Ti-6Al-4V and Ti-2.5Zr-1.5Mo, have higher strength with decreasing temperature.
It is high, but the plastic change is not great. In addition, these alloys retain good ductility and toughness at low temperatures ranging from - 196 to 253, thus avoiding the cold brittleness of metals. In other words, these materials are better resistant to deformation and damage at low temperatures. Because the temperature in space is very low, so satellites, space stations, rocket orbital capsules and space shuttles and other aeronautical equipment need good cryogenic resistance when operating in this environment. Titanium and titanium alloys have excellent low temperature resistance, which has become one of the important reasons for their wide application in the aviation industry.
6. Good corrosion resistance
Titanium and oxygen react easily and have strong passivation tendency. In the medium containing oxygen, titanium, like aluminium, generates a dense, strong adhesion and inert oxide film on its surface, thus protecting the matrix from corrosion. Moreover, when the medium temperature is lower than 315 C, the oxide film will recover or regenerate quickly even if it is damaged. This makes titanium unparalleled corrosion resistance of most metal materials - not only will it not be corroded by strong alkali, chlorine , chlorine solution, most organic acids , hydrochloric acid with a concentration of less than 7%, sulfuric acid with a concentration of less than 5%, nitric acid and aqua regia at room temperature, but even the sea water has no choice: someone once sunk a piece of titanium to the bottom of the sea, and it still shines when it is fished up five years later. Thus, the corrosion resistance of titanium is almost impeccable. As mentioned earlier, aerospace equipment rubs against the air during flight, resulting in a large amount of heat, which leads to the easy oxidation of its shell. However, because the oxide film of titanium is very dense, which can ensure that the internal metal does not react with oxygen, the use of titanium and its alloys as shell materials of aviation equipment can effectively prevent oxidation and corrosion. Therefore, titanium and titanium alloys are widely used in aviation.
7. Strong anti-damping ability
Compared with steel and copper, titanium has the longest vibration attenuation time after mechanical and electrical vibration. Because rockets, space shuttles and missiles and other aviation equipments are inevitably vibrated by air disturbance during flight, it is necessary for their materials to have excellent anti-damping properties, and titanium is able to meet this requirement. Therefore, titanium and its alloys play an extremely important role in the production and manufacture of aviation equipment and are widely used.
8. Various alloys formed
Liquid titanium can dissolve almost all metals, so it can form alloys with various metals, thus producing light alloys with high strength. The addition of the metal into aluminium can refine the grain size, and the alloy cast with copper can harden copper . Titanium can reduce the grain size of steel, and can also be used as deoxidizer to reduce the oxygen content of steel. In addition, the addition of titanium in stainless steel can reduce the carbon content . Such effects make titanium steel particularly tough and elastic. In addition, the metal can form solid solution, interstitial compound or intermetallic compound with magnesium, antimony, beryllium, chromium, vanadium and molybdenum. By these means, titanium can improve the properties of itself or other metal materials by forming alloys. This makes the material not only possess the aforementioned excellent characteristics, but also further enhance on this basis, creating better conditions for it to show itself in the aviation industry.
9. Large reserves
Titanium accounts for 0.63% of the total crustal mass, 61 times as much as copper, ranking ninth in all elements and seventh in metal elements. Titanium exists in almost all organisms, rocks, water bodies and soils . For example, the U.S. Geological Survey has analyzed 801 igneous rocks, of which 784 contain titanium . In fact, it is not uncommon for the global reserves of more than 10 million tons of titanium ore. Titanium ores are mainly ilmenite and rutile, widely distributed in the crust and lithosphere . By the end of 1995, the world rutile (including anatase) reserves and reserves were 33.3 million tons and 164.4 million tons, respectively, and the total amount of resources calculated by the content of titanium dioxide was about 230 million tons; the world ilmenite reserves and reserves were 274.3 million tons and 435.3 million tons, respectively, and the total amount of resources calculated by the content of titanium dioxide was about 1 billion tons . Obviously, titanium metal is almost inexhaustible and inexhaustible in nature, which can meet the astonishing demand for materials. The amount of materials used in the aviation field is just very large, so it is no doubt very wise to use titanium in this aspect of production and manufacture. Therefore, titanium is widely used in the aviation field.
10. Flammable powder
Titanium powder with very fine combustion value is a high-quality fuel for rocket, so it is widely used in this area .
11. Other reasons
In addition to the above factors, titanium has many excellent properties such as fatigue resistance, crack resistance , good toughness , which also laid a solid foundation for its wide application in the aviation industry.
In summary, titanium has many advantages, such as light weight, high hardness, high strength and specific strength, good plasticity, high temperature and low temperature resistance, corrosion resistance, damping resistance, various kinds of alloys formed, high natural content, flammable powder, fatigue resistance, crack resistance and good toughness, so it can obtain so much in the field of aerospace. Quantity and wide application are all reasonable. We believe that with the continuous development and improvement of titanium smelting and processing technology, its application in aviation will be more and more extensive.