Briefly describe what kind of metal titanium alloy is

Ultra-Thin Titanium Alloy Sheet are composite metal materials. Its main basic component is titanium, and then some other elements are added and then combined, and the combined material is titanium alloy, so it is called a combined metal material. However, after adding some other elements, the finished titanium alloy is mainly silver-gray and silver-white.

The properties of titanium are related to the content of carbon, nitrogen, hydrogen, and oxygen contained. The titanium alloy impurity content of the lips cannot exceed 0.1%, but its strength is low and its plasticity is high.

1. The proportion of titanium alloys used in the aerospace field is actually very high. In the current western countries, when titanium alloys are used, 60% of titanium alloys are used in the aerospace field, mainly because they are used in the aviation industry. Titanium alloy is closely related to the cycle of air and the heating and cooling of aviation.

2. Titanium alloy materials are also used in the cars we usually drive. For example, some heavy-duty vehicles we have seen, including some racing cars, also use titanium alloy materials. However, using titanium alloy materials in automobiles can effectively reduce fuel consumption and even the exhaust emissions generated in vehicles. Effective control is also formed.

Application areas of titanium alloy capillaries

The capillary titanium alloy pipe is atomized by pyrogen and the granules in the molten state are severely attacked at a high speed to the surface of the cleaned and unsmooth substrate to produce the required coating. The moment the particles hit the surface of the substrate hard, it will be deformed, and with the help of the "England" effect, a coating with a lamellar structure is produced. With many "overlapping continuous accumulation" of plastic deformation particles, the fusion between particles should be mostly mechanical equipment, and there must be a certain number of holes. In addition, if painting is carried out in the air, there is likely to be metal in the coating. mixed with oxides.

Titanium tubes are mainly used to make aero-engine compressor components, followed by rockets, cruise missiles and structural parts of high-speed airports. In the middle and late 1960s, titanium and aluminum alloys have been used in general industrial production to make electric grades for electrolytic industrial production, coolers in power plants, electric heaters for crude oil refining and seawater desalination equipment and their air pollution. Manipulating equipment, etc. Titanium and aluminum alloys have become a corrosion-resistant structural raw material. In addition, it is also used to produce hydrogen storage raw materials and shape memory alloys.

Capillary titanium alloy tube is a new key structural raw material used in aerospace industry production. Its proportion, compressive strength and application temperature are close to the middle of aluminum and steel, but it has high specific strength and excellent sea surface corrosion resistance and low temperature characteristics. In 1950, the United States used the F-84 fighter-bomber for the first time as a non-stressed prefabricated component such as the rear shell insulation material, wind deflector, and tail rudder cover. In the 1960s, the application position of Grade 9 Ti3Al2.5V Titanium Tube was gradually changed from the rear shell to the middle shell, and part of the structural steel was replaced to manufacture key prefabricated components such as bulkheads, beams, and flap guides. The use of titanium alloys in military aircraft has increased rapidly, reaching 20% ​​to 25% of the net weight of the airport structure. Since the 1970s, titanium alloys have been gradually used in civil aircraft. For example, the amount of titanium used in Boeing 747 passenger aircraft reaches more than 3640KG. Titanium for airports with Mach numbers lower than 2.5 is mainly to better replace steel to ease the net weight of the structure. Another example is the American SR-71 high-speed fighter plane (the flight Mach number is 3, and the aircraft flight altitude is 2621 two meters), titanium accounts for 93% of the net weight of the airport structure, which is called "all titanium" airport.

When the thrust-to-weight ratio of the aircraft engine is increased from 4 to 6 to 8 to 10, and the temperature of the compressor inlet and outlet is increased from 200 to 300 °C to 500 to 600 °C, the bottom pressure compressor discs and blades originally made of aluminum It is necessary to change to titanium alloy, or use titanium tube instead of stainless steel plate to manufacture high-pressure compressor discs and blades to reduce the net weight of the structure. In the 1970s, the use of titanium tubes in aircraft engines generally accounted for 20% to 30% of the total weight of the structure, and it was mainly used to manufacture compressor components, such as forged titanium cooling fans, compressor discs and blades, cast titanium compressors Receiver, intermediary company receiver, rolling bearing housing, etc. The space shuttle mainly uses the high specific strength, corrosion resistance and cold resistance properties of titanium tubes to manufacture a variety of high-pressure containers, natural material storage tanks, standard parts, equipment bandages, structures and rocket casings. Synthetic earth communication satellites, lunar modules, manned spacecraft and spacecraft also use titanium tube sheets for welding.

Application prospect of titanium alloy in biomedical field

With the development of the national economy and the improvement of people's living standards, the trend of population aging has become increasingly prominent, and diseases and accidental injuries have increased year by year. As an important branch of human tissue and organ regeneration and repair materials, biomedical titanium alloy materials have huge market prospects.

It should be clearly understood that my country's titanium alloy manufacturers still have a certain gap with the world's advanced level in terms of biomedical titanium alloy material design, preparation, and processing, surface treatment, product design, and manufacturing. Low cost, safety, and effectiveness will be an important direction for the application research of biomedical titanium alloys. The following issues are worthy of attention in future applications.

1. Optimize the composition design of medical titanium alloys

By improving the existing alloy system and creating a new alloy system, the development of low elastic modulus, reasonable matching of strength and toughness, wear resistance, corrosion resistance, fatigue resistance, and excellent biological and mechanical compatibility, can meet the needs of human soft and hard tissue repair and replacement New medical titanium alloy material for clinical application.

2. Innovative preparation method of medical titanium alloy materials

Establish and improve advanced theories and methods for the processing and preparation of medical titanium alloy materials, continuously deepen or innovate the preparation methods of porosity, micro-nano, amorphization, and ultra-fine crystallization of materials, and obtain special structures and structures through new preparation methods. Endow the material with biological functionalization and intelligence, and realize the optimization and upgrading of medical titanium alloy materials.

3. Expand research on surface modification of medical titanium alloys

Through the study of the mechanism of action between the titanium alloy and the base metal and the dual interface between the Tantalum Sputtering Target and human tissues or body fluids, find and screen various inorganic materials, polymer materials and cytokines to modify the surface of titanium alloys to improve their surface properties and structure. Structure, improve wear and corrosion resistance, biocompatibility and bioactivity and other performance.

4. Improve the technical level of material production and processing

At present, domestic processing technologies such as medical titanium alloy thick-walled tubes and titanium-nickel alloy capillaries are not very mature, and most of them need to be imported from abroad. Therefore, we especially need to master the core key technologies of titanium sheet metal processing, strengthen the construction of quality control system, and improve the consistency of product performance. properties, reduce processing and manufacturing costs, and further meet the manufacturing needs of medical titanium alloy products.

5. Strengthen product design and processing

It is the general trend to use advanced processing technologies such as precision casting, precision CNC machining, and micro-machining for the processing of medical devices. In particular, digital 3D reconstruction technology has become a hot spot in recent years. According to the patient's defect, the technology uses 3D CT. The examination results simulate the natural form, and rely on CT data processing for medical 3D reconstruction. Through the surface drawing of natural curved surfaces, computer graphics and image-aided design, and digital manufacturing of titanium alloys, the patient can be accurately designed and prefabricated with laser forming technology. Personalized instruments , has the advantages of customizability, strong consistency, less process, short cycle and so on. This is a revolutionary progress, marking the entry of titanium alloy instruments into the digital age, and will become one of the key development directions in the field of titanium alloy biomedicine.

Anti-fatigue Surface Modification of Titanium Alloys

While meeting the lightweight requirements of aerospace vehicles, titanium alloy parts also need to meet the requirements of long life and high reliability, which requires titanium alloy parts to have good fatigue resistance. However, medical titanium plate is a typical difficult-to-machine material. Adhesive wear of the tool during machining may cause complex surface stress. In addition, its poor thermal conductivity leads to a local temperature rise. Therefore, it is difficult to control the surface integrity of titanium alloy parts after machining. The industry uses a large number of anti-fatigue surface modifications (or surface deformation strengthening technology, Surfacemechanicaltreatment) to improve the surface integrity of titanium alloy parts, thereby achieving a long life and high-reliability requirements. In the anti-fatigue surface modification, mechanical shot peening (Shotpeening) and laser shock peening (Laser shock peening or Laserpeening) have strong structural adaptability and are widely studied in the industry. A series of researches have also been carried out on some surface strengthening technologies adapted to special structures, such as Cold expansion adapted to pore structures and Ultrasonic impact treatment or Ultrasonic impact peening adapted to welded structures.

The surface reaction layer of the titanium plate and titanium rod can be completely removed by pickling after sandblasting.

In addition to physical and mechanical polishing, there are two types of reaction layers on the surface of Grade 3 Pure Titanium Plate and titanium rods: 1. Chemical polishing, 2. Electrolytic polishing.

1. Chemical polishing:

During chemical polishing, the purpose of leveling and polishing is achieved through the redox reaction of metal in the chemical medium. The advantage is that chemical polishing has nothing to do with the hardness of the metal, the polishing area, and the structural shape, and all the parts in contact with the polishing liquid are polished, no special complicated equipment is required, and the operation is simple, and it is more suitable for the polishing of titanium denture brackets with complex structures. However, the process parameters of chemical polishing are difficult to control, and it is required to have a good polishing effect on the denture without affecting the accuracy of the denture. A better titanium chemical polishing solution is prepared by HF and HNO3 in a certain proportion. HF is a reducing agent, which can dissolve titanium metal and play a leveling role. The concentration is less than 10%. HNO3 plays an oxidizing role to prevent excessive dissolution of titanium and hydrogen absorption. , at the same time can produce bright effect. Titanium polishing liquid requires high concentration, low temperature and short polishing time (1-2min).

2. Electrolytic polishing:

Also known as electrochemical polishing or anodic dissolution polishing, due to the low conductivity and strong oxidation performance of titanium alloy tubes, it is almost impossible to polish titanium with aqueous acidic electrolytes such as HF-H3PO4 and HF-H2SO4 electrolytes. After the external voltage, the Grade 12 Titanium Sheet is oxidized immediately, so that the anode dissolution cannot be carried out. However, the use of anhydrous chloride electrolyte at low voltage has a good polishing effect on titanium. Small specimens can be mirror polished, but for complex restorations, the purpose of complete polishing can still not be achieved. It may be possible to change the shape of the cathode and add an additional cathode. The method can solve this problem, and further research is needed.

Application of titanium alloy plate in medical field

Titanium plate is a very common substance, and the purity of sponge titanium can reach 99.9%. The physical and chemical properties of titanium alloy products are very stable, they will not be absorbed by the human body, and they will not react chemically with body fluids and medicines, nor will they be ionized, nor will they react with the musculoskeletal body of the human body. Biophilic Metals". Because titanium is "biophilic", titanium in the human body can resist the corrosion of secretions and is non-toxic, and is suitable for any sterilization method. Therefore, the titanium plates produced by many titanium plate manufacturers are widely used in the manufacture of medical devices, the manufacture of human hip joints, knee joints, shoulder joints, flank joints, skull bones, active heart valves, and bone fixation clips.

Titanium metal materials are the earliest biomedical materials used in clinical medicine. Titanium plates are processed into Grade 23 Ti-6Al-4V ELI Titanium Sheet. The metal materials currently used for surgical implants and orthopedic instruments mainly include three series of stainless steel, cobalt-based alloys, and titanium alloys, which account for three major series. The market share of the entire biomaterial product is about 40%. Among them, titanium alloys have been widely used in the repair, orthopedic and replacement treatment of defects, trauma, and diseases of human hard tissues (including all bones and teeth in the human torso).

 Since the middle of the 20th century, medical metal materials based on titanium alloys have been shown in the surgical implantation of human hard tissues and the interventional treatment of human soft tissues (including cardiovascular and cerebrovascular, peripheral blood vessels, and non-vascular such as liver, biliary tract, urethra, etc.). It has a unique and miraculous curative effect, and titanium alloy artificial joints, dental implants, intravascular stents, and heart valves have the development, production, and application of titanium alloy materials for medical devices in China, and the advent of typical representative medical device products. The development of medicine has an epoch-making significance and revolutionary contribution, which makes the clinical treatment rise from the primary simple "repair and orthopedic" treatment to the higher-level "replacement" treatment of tissues and organs, which greatly improves and improves people's lives. The quality has overcome the deficiency that major diseases can only rely on drug treatment in the past.

Physical phenomena of titanium machining

The cutting force of titanium alloy processing is only slightly higher than that of steel with the same hardness, but the physical phenomenon of processing titanium alloy is much more complicated than that of processing steel, which makes titanium alloy processing face huge difficulties.

Why do we consider titanium alloys to be a difficult material to the machine? Due to the lack of understanding of its processing mechanism

The thermal conductivity of most Titanium Alloy Rectangular Tube is very low, with only 1/7 of steel and 1/16 of aluminum. Therefore, the heat generated in the process of cutting titanium alloys will not be quickly transferred to the workpiece or taken away by the chips but will accumulate in the cutting area, and the temperature generated can be as high as 1 000 °C or more, which will cause the cutting edge of the tool to rapidly wear, chip and crack. A built-up edge is created, which quickly causes a worn edge, which in turn generates more heat in the cutting area, further reducing tool life.

The high temperatures generated during the cutting process also destroy the surface integrity of titanium alloy parts, resulting in a decrease in the geometric accuracy of the part and work hardening that severely reduces its fatigue strength.

The elasticity of AMS 4928 Titanium Alloy Bar may be beneficial for part performance, but during cutting, the elastic deformation of the workpiece is an important cause of vibration. The cutting pressure causes the "elastic" workpiece to move away from the tool and bounce so that the friction between the tool and the workpiece is greater than the cutting action. The friction process also generates heat, aggravating the problem of poor thermal conductivity of titanium alloys.

This problem is even more serious when machining thin-walled or ring-shaped parts that are prone to deformation. It is not an easy task to machine thin-walled titanium alloy parts to the expected dimensional accuracy. Because when the workpiece material is pushed away by the tool, the local deformation of the thin wall has exceeded the elastic range and plastic deformation occurs, and the material strength and hardness of the cutting point increase significantly. At this point, machining at the previously determined cutting speed becomes too high, further resulting in sharp tool wear.