TC4 titanium alloy is an α-β type titanium alloy successfully developed by the United States in 1954, containing 6% α stabilizing elements and 4% β stabilizing element V. The nominal composition of TC4 titanium alloy is 6.0 aluminum equivalent, 4.0 vanadium equivalent, and 10%-15% β phase in the annealed state.
Al improves the room temperature strength and thermal strength of the alloy by solid solution strengthening the α phase in the Ti-Al-V system, while V is one of the few alloying elements in titanium alloys that can improve both strength and plasticity. V has a favorable effect on the plasticity of titanium alloys. Unlike most alloying elements, it does not increase the ratio of the c/a axis of the α state lattice, but reduces the ratio, thereby increasing the formation of the α phase and avoiding alloy embrittlement during long-term use.
The main characteristics of TC4 titanium alloy are excellent comprehensive performance 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 extension resistance in seawater, as well as satisfactory fracture toughness and resistance to hot salt stress corrosion. It is also less sensitive to hydrogen than TC2 and TC1 alloys. It is suitable for manufacturing various parts working in a wide temperature range of -196~450℃, especially parts designed using the damage tolerance limitation principle.
TC4 titanium alloy also has excellent process plasticity and superplasticity, and is suitable for forming by various pressure processing methods, and various methods of welding and machining. The main semi-finished products of TC4 titanium alloy are bars, forgings, thin plates, thick plates, profiles and wires, etc., and are also used for castings (ZTC4).
TC4ELI titanium alloy
TC4ELI titanium alloy has become an ideal material for medical surgical implants due to its good biocompatibility, low elastic modulus, low density, good corrosion resistance, non-toxicity, high yield strength, long fatigue life, large plasticity at room temperature, and easy forming. Medical TC4ELI titanium alloy plates are mainly used for skull repair and bone setting, which have higher requirements for its strength, fatigue life, plasticity, etc.
Titanium alloy is an alloy composed of titanium elements and other elements. Titanium has two isomorphs: titanium is an isomer with a melting point of 1668℃. It has a close-packed hexagonal lattice structure below 882℃, called α-titanium; it has a body-centered cubic lattice structure above 882℃, called β-titanium. By using the different characteristics of the above two structures of titanium, adding appropriate alloying elements, the phase transition temperature and component content are gradually changed to obtain titanium alloys with different structures.
TC4 ELI titanium alloy reduces the content of interstitial elements C, O, N and impurity element Fe on the basis of TC4 alloy, and 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 treatment, ships and aircraft.
TC4 alloy can be used in ordinary environment or high temperature environment, and TC4ELI alloy can be used in ultra-low temperature environment
TC4 titanium alloy and TC4ELI titanium alloy are similar in grades: T-6A-4V/Grade 5 (US grade), BT 6 (Russian grade), IMI 318 (British grade), TiAI6V4 (German grade).
Medical equipment manufacturing In the human body, bone and joint injuries caused by trauma and tumors, titanium and titanium alloys are used to make artificial joints, bone plates and screws, which are now widely used in clinical practice. It is also used in hip joints (including femoral heads), knee joints, elbow joints, metacarpophalangeal joints, interphalangeal joints, mandibles, artificial vertebrae (spinal orthotics), pacemaker housings, artificial hearts (heart valves), artificial dental implants, titanium nickel dental orthodontics, and titanium mesh in skull plastic surgery.
Titanium and titanium alloys are gaining increasing attention due to their high specific strength, biocompatibility, and good resistance to body fluid corrosion.
Ti 6Al-4V ELI is a grade of Ti 6Al-4V with a smaller interstitial space, which can achieve 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 of material in the field of medical implants.
The production process is: relaxation annealing at 900-120 degrees Fahrenheit for 1-4 hours, and air cooling. Double annealing, for bars and forgings, is solution annealing at 50-100°F beta transition temperature, hold for at least 1 hour, air cool, then reheat at 1300-1400°F, hold for at least 1 hour, air cool. Stress relaxation annealing is suitable after welding.
