The characteristics and functions of titanium and titanium alloys

       

The characteristics and functions of titanium and titanium alloys

The toxicological research on titanium and titanium compounds is still insufficient. However, research and practice have shown that titanium and TiO2 are biologically inert substances and non-toxic; insoluble compounds such as titanium hydride, titanium carbide, titanium nitride and titanium boride have very low toxicity and can cause slight fibrotic changes in animal lungs. TiCl4 can cause burns to human skin, is a strong irritant to mucous membranes and eyes, and has obvious toxic effects. Certain organic titanium compounds, such as titanocene, have carcinogenic effects on animals. Titanium square bars are now accepted by the human body as surgical implants, and certain titanium compounds can be used as raw materials for the production of cosmetics.

 

Titanium has metallic luster and ductility. The density is 4.5g/cm3, the melting point is 1668 degrees, and the boiling point is 3287 degrees. The valences are + 2, +3, and +4, and the ionization energy is 6.82 eV. The main characteristics of titanium are low density, high strength, and easy processing. The plasticity of titanium mainly depends on its purity. The purer the titanium, the greater the plasticity. Has good corrosion resistance.

 

①Small density, high strength, and high specific strength;

 

②Corrosion resistance;

 

③Good heat resistance;

 

④Good low temperature performance;

 

⑤No magnetism;

 

⑥Small thermal conductivity;

 

⑦Small modulus of elasticity;

 

⑧The tensile strength is close to the yield strength;

 

⑨Qin is easily oxidized at high temperature;

 

⑩ Low damping resistance.

 

The larger the specific surface area of the titanium material, the easier it is to hydrogenate, and vice versa. The influence of the composition of the titanium material on the hydrogenation process is particularly important. Pure titanium is easy to hydrogenate, and titanium alloys are slightly worse. Among them, Ti-17 (ie Ti-5A1-2Sn-2Zr-4Cr-4Mo) cannot be hydrogenated to make powder. The reason is not clear. The hydrogenation resistance of titanium is firstly related to the surface oxide film properties of titanium. Because the film is very dense, it becomes an effective barrier layer for hydrogen to penetrate the titanium. For this reason, this oxide film must be removed. Different cleaning methods are used for different film properties. If the oily titanium material is not purified, the oily dirt will be decomposed at high temperature during the hydrogenation process, and the precipitated carbon will adhere to the titanium surface and become a barrier layer on the titanium surface, reducing the effective surface area of the titanium surface and reducing the hydrogenation rate.