What are the advantages of titanium alloy compared with traditional metal materials?

Titanium alloy refers to a variety of alloy metals made of titanium and other metals. It has the characteristics of high strength, good corrosion resistance and high heat resistance. It is an important structural metal and is widely used in aviation, aerospace, ships, military industry, medical devices and other civilian fields.

Since 1950s, there are hundreds of titanium alloys developed in the world, among which BT20 ~ 30 are the most famous alloys, such as Ti-6Al-4V, Ti-5Al-2.5Sn, Ti-2Al-2.5Zr, Ti-32Mo, Ti-Mo-Ni, Ti-Pd, SP-700, and so on.

The properties of titanium are related to the contents of impurities such as carbon, nitrogen, hydrogen and oxygen. The purest titanium iodide contains no more than 0.1% impurities, but it has low strength and high plasticity. The properties of 99.5% industrial pure titanium are: density ρ=4.5g/cm3, melting point 1725℃, thermal conductivityλ= 15.24 w/(m k), tensile strengthσb=539MPa, elongationδ=25%, area shrinkageψ=25%, and elastic modulus E = 1.078. Compared with traditional metals, titanium has the following advantages:

The density of high-strength titanium alloy is about 4.51g/cm3, which is only 60% of that of steel, but its mechanical strength is equivalent to that of steel, and it has high strength, and its tensile strength is usually (686-1176)MPa. The tensile strength Rm of TC4 is about 1262 MPa. Some titanium alloys exceed the strength of many alloy structural steels, so the specific strength (strength/density) of titanium alloys is much higher than that of other metal structural materials, and parts with high unit strength, good rigidity and light weight can be made. Aircraft engine components, skeleton, skin, fasteners and landing gear are all made of titanium alloy.

In the air with corrosion resistance below 550℃, a dense, adhesive and inert oxide film is formed on the surface of titanium, which protects the titanium matrix from corrosion, and even due to mechanical wear, it will heal itself or regenerate quickly, and the oxide film of titanium always maintains this characteristic when the medium temperature is below 315℃, so the corrosion resistance of titanium alloy is better than that of most stainless steels in oxidizing media such as atmosphere, seawater, nitric acid and strong alkali. This is the basic guarantee for the use of titanium in civil industries in various countries.

Good high temperature resistance The high temperature titanium alloy developed by solid solution strengthening α phase can be used for a long time below 600℃ and for a short time below 800℃. When the flight speed Mach number of the aircraft is higher than 2.7, the disk, blades, aft fuselage, guide, intake box and other parts of the engine are made of high-temperature titanium alloy.

Biocompatible metal titanium is a biophilic metal, which has very good biocompatibility. It can be "compatible" when it comes into contact with the human body or implanted in the body without causing harm to the human body. Titanium in human body can resist the corrosion of secretions and is non-toxic, so it has been adopted by the medical community for artificial joints, cardiac pacemakers and other equipment. Studies have shown that titanium implants can trigger the human immune system to grow bones directly on the surface of titanium, a process called osseointegration. It shows that titanium is completely "biocompatible", which means that it is non-toxic, does not cause allergic and rejection reactions, and can even be fused with human tissues and bones.

As a high-end material, titanium alloy has been applied in aerospace and cutting-edge military industry. At present, with the maturity of technology, titanium alloy, as an increasingly common metal material, has been widely used in ships, chemical equipment, oceans, sports equipment, medical implants, automobiles, motorcycles, bicycles, buildings, daily necessities and other fields.