Characteristics and applications of titanium and titanium alloys

Characteristics and applications of titanium and titanium alloys
Pure titanium has low strength and high melting point, but has high specific strength, good plasticity and low-temperature toughness, good corrosion resistance, and is easy to process and shape. Pure titanium has excellent corrosion resistance in the atmosphere and seawater, and is stable in sulfuric acid, hydrochloric acid, nitric acid and other media. As the purity of titanium decreases, the strength increases and the plasticity decreases greatly.
It has extremely high chemical activity and reacts strongly with Cl, O, S, C, N, etc. (at high temperatures). In the liquid state, it reacts with almost all crucibles except ThO2. It can only be smelted in a vacuum electric arc furnace.
Good weldability; good stamping performance; but poor wear resistance; low elastic modulus (120GPa), about 54% of iron; low thermal conductivity and linear expansion coefficient. Its thermal conductivity is several times lower than that of iron, and it is prone to temperature gradients and thermal stress during use.

Adding alloying elements to pure titanium improves and strengthens its properties to form a titanium alloy, which has high strength, heat resistance, and corrosion resistance. It has non-magnetic properties, low damping characteristics of sound waves and vibrations, good biocompatibility, and is compatible with carbon. Composite materials have good compatibility and have excellent properties such as superconducting properties, shape memory and hydrogen absorption properties. However, they also have some shortcomings, such as difficult hot processing, poor cold working performance, poor cutting processability, and poor wear resistance.
Titanium alloy classification: α-Titanium alloy has good high temperature performance (<500℃), good structural stability, and good weldability. It is the main component of heat-resistant titanium alloy, but it cannot be strengthened by heat treatment, has low strength at room temperature, and low plasticity;
αβ titanium alloy: high strength at room temperature, can be strengthened by heat treatment, but the structure is not stable enough; the welding performance is poor;
β-titanium alloy and near-β titanium alloy: have good plastic processing properties (quick cooling to obtain β structure), high mechanical properties (strength can be improved through aging), and have the greatest potential for the development of high-strength (tensile strength >1400-1500MPa) titanium alloys. alloy, but the structural stability is poor and the working temperature is lower than 200 degrees
At present, only carbon fiber reinforced plastics have a higher specific strength than titanium alloys, and titanium alloys are the metal materials with the highest specific strength. Therefore, it is also called "space metal", which is the main reason why titanium alloy is widely used in the aviation industry. For example, in aircraft engines, titanium alloys are commonly used as compressor disks, compressor blades, engine covers, combustion chamber casings, and jet pipes.

Application areas of titanium and titanium alloys
Aerospace: jet engine components, fuselage components, rockets, satellites, missiles and other components
Compressor and fan blades, discs, casings, guide vanes, shafts, landing gear, flaps, spoilers, engines
Nacelle, bulkheads, wing spars, fuel tanks, boosters
Chemistry, petrochemicals and general industry: electrolyzers, reactors, steamers for chlor-alkali, soda ash, plastics, petrochemicals, metallurgy, salt making and other industries
Distillation columns, concentrators, separators, heat exchangers, pipes, electrodes, etc.
Ship: Submarine pressure hull, propeller, water jet propeller, seawater heat exchange system, ship pump (valves and pipes)
Marine engineering: pipelines for seawater desalination, pumps, valves, pipe fittings for offshore oil drilling, etc.
Biomedicine: artificial joints, artificial dental implants and orthodontics, pacemakers, cardiovascular stents, surgical instruments, etc.
Sports equipment: golf heads, tennis rackets, badminton rackets, billiard cues, hiking sticks, ski poles, ice skates, etc.
Daily necessities: glasses frames, watches, crutches, fishing rods, kitchen utensils, digital product cases, handicrafts, decorations, etc.
Construction: Roofs, exterior walls, decorations, signs, railings, pipes, etc. of buildings
Automobile: automobile exhaust and silencer systems, load-bearing springs, connecting rods and bolts, etc.