Ti-6Al-4V titanium alloy has the advantages of low density, high specific strength, excellent toughness, good corrosion resistance, good machining performance and so on. It is an ideal structural material for aerospace engineering.
Titanium alloy is a new structural material, it has excellent comprehensive properties, such as low density (~4.5g cm-3), high specific strength and fracture toughness, fatigue strength and crack growth resistance, good low temperature toughness, excellent corrosion resistance, some titanium alloy maximum working temperature is 550ºC, expected to reach 700ºC. Therefore, it is increasingly widely used in aviation, chemical industry, medical treatment, shipbuilding and other industrial sectors, and develops rapidly.
Another significant feature of titanium is strong corrosion resistance, which is the affinity of titanium to oxygen is particularly large, can generate a layer of dense oxide film on its surface, can protect titanium from corrosion by the medium. Titanium can form passivated oxide films on the surface in most aqueous solutions. Therefore, titanium has good stability in acidic, alkaline, neutral salt aqueous solution and oxidizing medium, but in a certain medium, can continuously dissolve titanium surface oxide film, titanium will be corroded in this medium. For example, in hydrofluoric acid, concentrated hot HYDROchloric acid, fluid acid and phosphoric acid, titanium is corroded because the solution dissolves the oxide film on the surface of titanium. If oxidizing agents or some metal ions are added to these solutions, the titanium surface oxide film will be protected.
