The difference and relationship between TC4 titanium alloy and TC4ELI titanium alloy
TC4 titanium alloy is an α-β titanium alloy successfully developed by the United States in 1954. It contains 6% α-stabilizing elements and 4% β-stabilizing element V. The nominal composition of TC4 titanium alloy is 7.0 aluminum equivalent, 2.9 molybdenum equivalent, and contains 10%-15% beta phase in the annealed state. Al improves the room temperature strength and thermal strength properties of the alloy by solid solution strengthening the α phase in the Ti-Al-V system, and V is one of the few alloy elements in titanium alloys that can both increase strength and improve plasticity. The beneficial effect of V on the plasticity of titanium alloys is that it does not increase the ratio of the α-state lattice c/a axis like most alloy elements, but reduces the ratio, thereby improving the formation of the α phase and avoiding long-term use. Alloy embrittlement occurs during the process.
The main characteristics of TC4 titanium alloy are excellent comprehensive properties and good process performance. TC4 titanium alloy has moderate room temperature strength and high temperature strength, good creep resistance and thermal stability, high fatigue resistance and crack propagation resistance in seawater, as well as satisfactory fracture toughness and resistance to thermal salt stress corrosion. It is also less sensitive to hydrogen than TC2 and TC1 alloys, and is suitable for manufacturing various parts working in a wide temperature range of -196~450°C, especially parts designed using the damage tolerance limitation principle. TC4 titanium alloy also has excellent process plasticity and superplasticity, and is suitable for forming using various pressure processing methods, and for welding and machining in various ways.
The main semi-finished products of TC4 titanium alloy are bars, square discs, discs, thin plates, thick plates, profiles and wires, etc., which are also used in castings (ZTC4).
TC4ELI titanium alloy
TC4ELI is an improved version of TC4. Its main difference is the different Al content and lower content of interstitial elements Fe, N, H, and O.
TC4ELI titanium alloy has become a medical surgical implant due to its good biocompatibility, low elastic modulus, low density, good anti-corrosion properties, non-toxicity, high yield strength, long fatigue life, large plasticity at room temperature, and easy forming. ideal material for things. Medical TC4ELI titanium alloy plates are mainly used in skull repair, bone grafting, etc., which have higher requirements on strength, fatigue life, plasticity, etc.
Titanium alloy is an alloy composed of titanium as the base and other elements added. Titanium has two isomorphous crystals: titanium is an isomer with a melting point of 1668°C. It has a close-packed hexagonal lattice structure below 882°C, which is called α-titanium; it is a body-centered cubic structure above 882°C. The fret structure is called beta-titanium. By utilizing the different characteristics of the above two structures of titanium, adding appropriate alloying elements to gradually change the phase transformation temperature and component content, titanium alloys with different structures are obtained.
TC4 ELI titanium alloy is based on TC4 alloy and reduces the content of interstitial elements C, O, N and impurity element Fe. The strength is reduced, but the toughness can be significantly improved. TC4 ELI has good plasticity, toughness, good welding performance and low-temperature performance, and is widely used in important fields such as cryogenic engineering, medical care, ships and aircraft.
TC4 alloy can be used in ordinary or high-temperature environments, and TC4ELI alloy can be used in ultra-low-temperature environments.
TC4 titanium alloy and TC4ELI titanium alloy have similar grades: T-6A-4V/Grade 5 (American grade), BT6 (Russian grade), IMI318 (British grade), TiAI6V4 (German grade).
Medical equipment manufacturing: For bone and joint injuries caused by trauma and tumors in the human body, titanium and titanium alloys are used to manufacture artificial joints, bone plates and screws, which are now widely used in clinical applications. Also used in hip joints (including femoral heads), knee joints, elbow joints, metacarpophalangeal joints, interphalangeal joints, mandibles, artificial vertebrae (spinal orthoses), pacemaker shells, artificial hearts (heart-shaped valves) , artificial dental implants, titanium-nickel orthodontics and titanium mesh in skull plastic surgery, etc.
Titanium and titanium alloys are receiving increasing attention due to their high specific strength, biocompatibility, and good corrosion resistance to body fluids.
Ti 6Al-4V ELI is a grade of Ti 6Al-4V with smaller structural gaps, which can achieve maximum toughness and is suitable for seawater and low-temperature environments. This grade of alloy is usually used in the annealed condition. Ti 6Al-4V is a better choice material in the field of medical implants.
The production process is: relaxation annealing and air cooling at 900-120 degrees Fahrenheit for 1-4 hours. Double annealing, round bars and forgings are solution annealed at a beta transition temperature of 50-100 degrees Fahrenheit, held for at least 1 hour, then air cooled, then reheated at 1300-1400 degrees Fahrenheit, held for at least 1 hour, and then air cooled . Relaxation annealing is suitable after welding
