The difference between TC4 and TC4ELI in titanium alloys

TC4 titanium alloy

TC4 titanium alloy was successfully developed by the United States in 1954 α-β Type titanium alloy, containing 6% α Stable elements and 4% β Stable element V. The nominal composition of TC4 titanium alloy has an aluminum equivalent of 7.0, a molybdenum equivalent of 2.9, and an annealed state containing 10% -15% β Xiang. Al strengthening through solid solution in Ti-Al-V system α V is one of the few alloying elements in titanium alloys that can improve both strength and plasticity by enhancing the room temperature strength and thermal strength performance of the alloy. The favorable effect of V on the plasticity of titanium alloys is because it does not increase as much as most alloying elements do α The ratio of the c/a axis in the state lattice is reduced, thereby increasing α Formation of phases to avoid 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 propagation resistance in seawater, as well as satisfactory fracture toughness and resistance to hot salt stress corrosion. Its sensitivity to hydrogen is also smaller than TC2 and TC1 alloys, making it suitable for manufacturing various parts working in a wide temperature range of -196-450 ℃, especially those designed using the principle of damage capacity limitation. TC4 titanium alloy also has excellent process plasticity and superplasticity, suitable for forming using various pressure processing methods, and welding and mechanical processing using various methods.

The main semi-finished forms of TC4 titanium alloy are bars, forgings, thin plates, thick plates, profiles, and wires, which are also used in castings (ZTC4).

TC4ELI titanium alloy

TC4ELI is an improved version of TC4, with the main difference being different levels of Al and lower levels of interstitial elements Fe, N, H, and O.

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, high plasticity at room temperature, and easy formability. Medical TC4ELI titanium alloy plates are mainly used for skull repair, bone grafting, and other aspects, which have higher requirements for their strength, fatigue life, plasticity, etc.

Titanium alloy is an alloy composed of titanium element as the base and other elements added. There are two types of homogeneous and heterogeneous crystals of titanium: titanium is an isomer of the same element, with a melting point of 1668 ℃. When it is below 882 ℃, it exhibits a densely packed hexagonal lattice structure, known as α- Titanium; It exhibits a body centered cubic lattice structure above 882 ℃, known as β- Titanium. By utilizing the different characteristics of the two structures of titanium mentioned above, appropriate alloying elements are added to gradually change the phase transition temperature and component content, resulting in titanium alloys with different microstructures.

TC4 ELI titanium alloy reduces the content of interstitial elements C, O, N, and impurity elements Fe on the basis of TC4 alloy, resulting in a decrease in strength but significantly improving toughness. TC4 ELI has good plasticity, toughness, good welding performance, and low-temperature performance, and is widely used in important fields such as low-temperature engineering, medical, ships, and aircraft.

TC4 alloy can be used in normal or high-temperature environments, while TC4ELI alloy can be used in ultra-low temperature environments

TC4 titanium alloy has similar grades to TC4ELI titanium alloy, including T-6A-4V/Grade 5 (American grade), BT 6 (Russian grade), IMI 318 (British grade), and TiAI6V4 (German grade).

Medical equipment manufacturing uses titanium and titanium alloy to manufacture artificial joints, plates, and screws for bone and joint injuries caused by trauma and tumors in the human body, and has been widely used in clinical practice. It is also used for hip joints (including the femoral head), knee joints, elbow joints, metacarpophalangeal joints, interphalangeal joints, mandibles, artificial vertebral bodies (spinal orthotics), cardiac pacemaker shells, artificial hearts (heart shaped valves), artificial dental implants, titanium nickel orthodontic appliances, and titanium mesh in skull plastic surgery.

Titanium and titanium alloys are increasingly being valued due to their high specific strength, good biocompatibility, and resistance to liquid corrosion.

Ti 6Al-4V ELI is a grade of Ti 6Al-4V with small tissue gaps, which can achieve maximum toughness and is suitable for seawater and low-temperature environments. This grade of alloy is usually used in an annealed state. Ti 6Al-4V is a good 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. The process for double annealing, round bars, and forgings is: solution annealing at a beta transition temperature of 50-100 degrees Fahrenheit, followed by air cooling for at least 1 hour, followed by reheating at 1300-1400 degrees Fahrenheit, followed by air cooling for at least 1 hour. Relaxation annealing is suitable for post welding