The difference between TC4 and TC4ELI of titanium alloy

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 aluminum equivalent of 7.0 and a molybdenum equivalent of 2.9, and the annealing state contains 10%-15% β phase. Al improves the room temperature strength and thermal strength properties of Ti-Al-V alloy by strengthening α phase in solid solution, and V is one of the few alloy elements that can improve both strength and plasticity. The favorable effect of V on the plasticity of titanium alloys 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, thereby improving the formation of the α phase and avoiding the occurrence of alloy embrittleness during long-term use.

The main characteristics of TC4 titanium alloy are excellent comprehensive properties and good process properties. TC4 titanium alloy has moderate room temperature strength and high temperature strength, good creep resistance and thermal stability, high fatigue resistance and crack growth resistance in seawater, as well as satisfactory fracture toughness and thermal salt stress corrosion resistance, and its sensitivity to hydrogen is smaller than TC2 and TC1 alloys. It is suitable for manufacturing various parts working in a wide temperature range of -196~450 ° C, especially parts designed with the principle of damage tolerance limitation. TC4 titanium alloy also has excellent process plasticity and superplasticity, which is suitable for forming with various pressure processing methods, and welding and machining in various ways.

TC4 titanium alloy's main semi-finished forms are bars, forgings, sheets, thick plates, profiles and wire materials, etc., and are also used in castings (ZTC4).

TC4ELI titanium alloy

TC4ELI is an improved version of TC4, which is mainly different in Al content and lower content of interstitial 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 has become an ideal material for medical and 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. Titanium has two kinds of isomeric crystals: titanium is an isomer with a melting point of 1668 ° C and a close-packed hexagonal lattice structure below 882 ° C, called α-titanium; Above 882℃, it is a body-centered cubic character structure, called β-titanium. By using the different characteristics of the above two structures of titanium, appropriate alloying elements are added, so that the phase transition temperature and component content are gradually changed to obtain titanium alloys with different structures.
On the basis of TC4 alloy, TC4 ELI titanium alloy reduces the content of interstitial elements C, O, N and impurity elements Fe, and the strength is reduced, but the capacitance toughness can be significantly improved. TC4 ELI has good plasticity, toughness, good welding performance and low temperature performance, and is widely used in cryogenic engineering, medical treatment, 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 grades are: T-6A-4V/Grade 5 (American grade), BT 6 (Russian grade), IMI 318 (British grade), TiAI6V4 (German grade).

Medical equipment manufacturing in the human body due to trauma, tumor caused by bone, joint injury, the use of titanium and titanium alloy to manufacture artificial joints, bone plates and screws, has been widely used in clinical. It is also used for hip joints (including femoral head), knee joints, elbow joints, metacarpal and phalangeal joints, interphalangeal joints, mandibles, artificial vertebrae (spinal orthosis), cardiac pacemaker shell, artificial heart (heart-shaped valve), artificial dental implants, titanium nickel orthodontics and titanium mesh in cranial orthopedics, etc.

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

The Ti 6Al-4V ELI is a Ti 6Al-4V grade with a smaller tissue gap, which allows for maximum toughness and is suitable for seawater and low temperature environments. This grade of alloy is usually used in the annealed state. Ti 6Al-4V is a good choice in the field of medical implantation.

The production process is: relaxation annealing and air cooling in 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 degrees Fahrenheit, air cooling after holding for at least 1 hour, then reheating at 1300-1400 degrees Fahrenheit, air cooling after holding for at least 1 hour. Relaxation annealing is suitable for after welding.