Comparison between GR5 titanium alloy and GR5ELI titanium alloy
The nominal composition of GR5 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 features of GR5 titanium alloy are excellent comprehensive properties and good process performance. GR5 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 Ti-4AL-1.5Mn and Ti-2AL-1.5Mn 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. GR5 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 GR5 titanium alloy are bars, forgings, thin plates, thick plates, profiles and wires, etc., which are also used in castings (ZGR5).
GR5ELI titanium alloy
GR5ELI is an improved version of GR5. Its main difference is the different Al content and lower content of interstitial elements Fe, N, H, and O.
GR5ELI 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 GR5ELI titanium alloy plates are mainly used for 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.
And the content of the impurity element Fe, the strength is reduced, but the toughness can be significantly improved. GR5 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.
GR5 alloy can be used in normal environment or high temperature environment, and GR5ELI alloy can be used in ultra-low temperature environment.
GR5 titanium alloy and GR5ELI titanium alloy have similar grades: T-6A-4V/Grade 5 (American grade), BT 6 (Russian grade), IMI 318 (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: medium relaxation annealing at 900-120 degrees Fahrenheit for 1-4 hours and air cooling. 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.
