TC4 titanium alloy

TC4 titanium alloy is anα-βtitanium 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 has an aluminum equivalent of 7.0 and a molybdenum equivalent of 2.9,with 10%-15%βphase in the annealed state.In the Ti-Al-V system,Al enhances the room temperature strength and thermal strength of the alloy by solid solution strengthening of theαphase,while V is one of the few alloying elements in titanium alloys that can both improve strength and enhance plasticity.The beneficial effect of V on the plasticity of titanium alloys is due to its ability to reduce the ratio of c/a axes in theα-phase lattice,unlike most alloying elements which increase this ratio,thereby promoting the formation of theαphase and avoiding alloy embrittlement during long-term use.

The main characteristics of TC4 titanium alloy are its excellent comprehensive performance and good processability.TC4 titanium alloy possesses 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 lower than that of TC2 and TC1 alloys,making it suitable for manufacturing various parts that operate within a wide temperature range from-196 to 450℃,especially components designed using the damage tolerance principle.TC4 titanium alloy also exhibits excellent process plasticity and superplasticity,making it suitable for forming using various pressure processing methods,as well as welding and machining in various ways.

The main semi-finished products of TC4 titanium alloy include bars,forgings,thin plates,thick plates,profiles,and wires,and it is also used for castings(ZTC4).

TC4ELI titanium alloy

TC4ELI is an improved version of TC4,with the main differences being different Al content and lower contents of interstitial elements such as Fe,N,H,and O.

TC4ELI titanium alloy has become an ideal material for medical surgical implants due to its excellent biocompatibility,low elastic modulus,low density,good corrosion resistance,non-toxicity,high yield strength,long fatigue life,high plasticity at room temperature,and ease of forming.Medical TC4ELI titanium alloy plates are mainly used for cranial bone repair,bone grafting,and other applications,which require higher strength,fatigue life,and plasticity.

Titanium alloys are alloys composed of titanium as the base element with the addition of other elements.Titanium has two allotropic forms:titanium is an allotrope,with a melting point of 1668℃.Below 882℃,it adopts a hexagonal close-packed lattice structure,known asα-titanium;above 882℃,it adopts a body-centered cubic lattice structure,known asβ-titanium.By utilizing the different characteristics of these two structures of titanium and adding appropriate alloying elements,the phase transition temperature and component content can be gradually altered to obtain titanium alloys with different microstructures.

TC4 ELI titanium alloy,based on TC4 alloy,has reduced the content of interstitial elements C,O,N,and impurity element Fe,resulting in a decrease in strength but a significant improvement in toughness.TC4 ELI possesses excellent 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.

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

The similar grades of TC4 titanium alloy and TC4 ELI titanium alloy include:T-6A-4V/Grade 5(American grade),BT 6(Russian grade),IMI 318(British grade),and TiAI6V4(German grade).

Medical equipment manufacturing utilizes titanium and titanium alloys to produce artificial joints,bone plates,and screws for treating bone and joint injuries caused by trauma or tumors in the human body.These products are now widely used in clinical settings.They are also applied in hip joints(including femoral heads),knee joints,elbow joints,metacarpophalangeal joints,interphalangeal joints,mandibular bones,artificial vertebral bodies(spinal orthoses),cardiac pacemaker casings,artificial hearts(heart valves),dental implants,titanium-nickel orthodontic appliances,and titanium meshes for cranial plastic surgery.

Titanium and titanium alloys are gaining increasing attention due to their high specific strength,good biocompatibility,and excellent resistance to body fluid corrosion.

Ti 6Al-4V ELI is a grade with smaller intergranular spacing in Ti 6Al-4V,which allows for maximum toughness and is suitable for seawater and low-temperature environments.This grade of alloy is typically used in the annealed state.Ti 6Al-4V is a preferred material choice in the field of medical implants.

The production process is as follows:stress relief annealing and air cooling at 900-1200°F for 1-4 hours.For double annealing,the process for round bars and forgings is as follows:solution annealing at a beta transition temperature of 50-100°F,maintaining for at least 1 hour before air cooling,followed by reheating at 1300-1400°F,maintaining for at least 1 hour before air cooling.Stress relief annealing is suitable to be performed after welding