The difference between TC4 and TC4ELI of titanium alloy

TC4 titanium alloy

TC4 titanium alloy is an α-β titanium alloy successfully developed by the United States in 1954, containing 6% α stable element and 4% β stable element V. The nominal composition of TC4 titanium alloy has an Al equivalent of 7.0 and Mo equivalent of 2.9, and the annealing state contains 10%-15%β phase. The titanium pipe manufacturer believes that Al improves the room temperature strength and thermal strength of the alloy through solid solution strengthening of α phase in the Ti-Al-V system, and V is one of the few alloy elements in titanium alloys that can improve both strength and plasticity. The favorable effect of V on the plasticity of titanium alloy is that it does not increase the ratio of the c/a axis of the α state lattice, as most alloying elements do, but reduces the ratio, thus improving the formation of α phase and avoiding the embrittleness of the alloy in the course of long-term use.

The main characteristics of TC4 titanium alloy are excellent comprehensive performance and good technological performance. TC4 alloys have moderate room temperature strength and high temperature strength, good creep resistance and thermal stability, high fatigue resistance and crack propagation resistance in seawater, satisfactory fracture toughness and thermal salt stress corrosion resistance, and less sensitivity to hydrogen than TC2 and TC1 alloys. Suitable for manufacturing -196~450℃ wide temperature range of various parts, especially using the principle of damage tolerance design parts. TC4 titanium alloy also has excellent process plasticity and superplasticity, suitable for forming with a variety of pressure processing methods, and a variety of ways for welding and machining.

TC4 titanium alloy main semi-finished form for bar, forging, sheet, thick plate, profile and wire, etc., also used in castings (ZTC4).

TC4ELI titanium alloy

TC4ELI is an improved version of TC4. Its main difference is the different content of Al and the lower content of gap elements Fe, N, H and O.

TC4ELI titanium alloy has the advantages of good biocompatibility, low elastic modulus, low density, good anti-corrosion performance, non-toxic, high yield strength, long fatigue life, large plasticity at room temperature, easy to form and so on, and become the ideal material for medical surgical implants. Medical TC4ELI titanium alloy plate is mainly used for skull repair, bone grafting and other aspects, which has higher requirements for its strength, fatigue life, plasticity and so on.

Titanium alloy is an alloy composed of titanium and other elements. There are two kinds of isocrystals of titanium: titanium is an isomer with a melting point of 1668℃ and a close-packed hexagonal lattice structure below 882℃, which is called α-titanium; At 882℃ above the body - centered cubic character structure, known as beta - titanium. By making use of the different characteristics of the two structures of titanium alloys, appropriate alloying elements are added to make the phase transition temperature and component content of the alloys change gradually and a titanium alloy of different microstructure is obtained.

On the basis of TC4 alloy, TC4ELI titanium alloy reduces the content of gap elements C, O, N and impurity elements Fe, and the strength is reduced, but the toughness can be significantly improved. TC4ELI has good plasticity, toughness, good welding performance and low temperature performance, widely used in cryogenic engineering, medical, ships and aircraft and other important fields.

TC4 alloy can be used in ordinary environment or high temperature environment, TC4ELI alloy can be used in ultra-low temperature environment TC4 titanium alloy and TC4ELI titanium alloy similar brand: T-6A-4V/Grade 5 (US grade), BT 6 (Russian grade), IMI 318 (UK grade), TiAI6V4 (German grade).

Medical equipment is manufactured in the human body due to injuries, tumors caused by bone and joint injuries, the use of titanium and titanium alloy to manufacture artificial joints, bone plates and screws, has been widely used in the clinic. It is also used for hip joint (including femoral head), knee joint, elbow joint, metacarpal joint, interphalangeal joint, mandible, artificial vertebral body (spine orthosis), cardiac pacemaker shell, artificial heart (heart valve), artificial dental implant, titanium nickel orthodontic device and titanium mesh in cranial reconstruction, etc.

Titanium and titanium alloys are getting more and more attention because of their high specific strength, biocompatibility and good resistance to body fluids.

Ti6Al-4VELI is a Ti6Al-4V model with a smaller tissue gap, thus achieving maximum toughness and suitable for seawater and low temperature environments. This grade of alloy is usually used in the annealed state. Ti6Al-4V is a good choice in the field of medical implantation.

The production process is: pressure annealing and air cooling at 900-120 degrees F for 1-4 hours. The process for double annealing, round rods and forgings is: solid solution annealing at a beta transition temperature of 50-100 F, air cooling after holding for at least 1 hour, then reheating at 1300-1400 F, air cooling after holding for at least 1 hour. Relaxation annealing is suitable for after welding.

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