Titanium metal performance analysis

Generally, aluminum loses its original properties at 150°C, stainless steel loses its original properties at 310°C, and titanium alloys still maintain good mechanical properties at around 500~600°C. When the aircraft speed reaches Mach 2.7, the surface temperature of the aircraft structure reaches 230°C. Aluminum alloys and magnesium alloys are no longer available, but titanium alloys can meet the requirements. Titanium has good heat resistance and is used in the disks and blades of aircraft engine compressors and in the skin of aircraft rear fuselages.

The strength of some titanium alloys (such as Ti-5Al-2.5SnELI) increases as the temperature decreases, but the plasticity does not decrease much. It still has good plasticity and toughness at low temperatures and is suitable for use at ultra-low temperatures. It can be used in liquid hydrogen and liquid oxygen rocket engines, or as ultra-low temperature containers and storage tanks on manned spacecraft.

Titanium itself is non-magnetic, and titanium alloys that do not contain iron are also non-magnetic, so magnetic interference can be effectively avoided. Used for submarine shells and will not cause mine explosions. In addition to being used in national defense, air force, and weapons manufacturing, it is also widely used in railway engineering, communications, aerospace, aviation, high-tech laboratories, hospitals (scans, X-rays, magnetic resonance imaging, electrocardiograms, cathode ray tubes), medicine, nuclear Industry, nuclear magnetic resonance, magnetic spectrometer, high Tesla magnet, outdoor operations, dock construction, diving, chemical industry, fire protection, desalination, shipbuilding, offshore oil and gas platforms, salt industry, etc.

The thermal conductivity of titanium alloy is small, that is, it heats up quickly and conducts heat slowly. Its thermal conductivity is only 1/5 of steel, 1/13 of aluminum, and 1/25 of copper. Poor thermal conductivity is a disadvantage of titanium, but this property of titanium can be exploited in some cases.

Titanium's elastic modulus is only half that of steel. When used as a structural material, its low elastic modulus is a disadvantage and it is prone to deflection.

Tensile strength and yield strength of titanium

The tensile strength of Ti-6Al-4V titanium alloy is 960MPa and the yield strength is 892MPa. The difference between the two is only 58MPa. This characteristic causes titanium to produce large springback during processing, which needs to be overcome.

Titanium has a strong binding force with hydrogen and oxygen. Care should be taken to prevent oxidation and hydrogen absorption. Titanium welding should be carried out under argon protection to prevent contamination. Titanium tubes and plates must be heat treated under vacuum, and the micro-oxidation atmosphere must be controlled during heat treatment of titanium forgings.

Identical clocks in shape and size are made of titanium and other metallic materials (copper, steel). When different bells were struck with the same force, we found that the sound lasted longer when the bell made of titanium oscillated, that is, the energy given to the bell by striking did not disappear easily, indicating that titanium has lower damping properties and can be used Make a variety of musical instruments.

Titanium's shape memory function, superconducting function and hydrogen absorption function are called the three special functions of titanium and titanium alloys.

Titanium shape memory function

A certain proportion of Ti-Ni alloy can restore its original shape under certain temperature conditions, that is, it has a shape memory function. This material is called a shape memory alloy. Today, shape memory alloys are widely used in aerospace, marine, weapons, medical and industrial applications.

When the temperature drops to near zero, wires made from a niobium-titanium alloy lose resistance and become superconducting. When any large current passes through, the wire will not heat up and consume no energy. Nb-Ti is called a superconducting material.

A certain proportion of Ti-Fe alloy has the ability to absorb large amounts of hydrogen. Using this characteristic, hydrogen can be stored safely, and under certain conditions, the stored Ti-Fe alloy can be used to release hydrogen, which provides an alternative to the use of steel high-pressure gas cylinders for hydrogen storage. This property is called the hydrogen absorption function of titanium, and materials with this function are called energy storage materials.