Titanium alloy has high specific strength and specific stiffness, strong corrosion resistance, good fatigue resistance and creep resistance.
As well as high temperature mechanical properties and good comprehensive properties. Currently titanium and titanium alloys are mainly used in aerospace and in the military industry. According to statistics, the application of titanium in aerospace accounts for about 70% of the total titanium. In addition, titanium and its alloys are also ideal materials for realizing the lightweight of automobiles, which can reduce weight when applied to automobile-related parts.
Energy saving and noise reduction, thereby improving the safety and comfort of the car. However, the application of titanium alloys is greatly limited due to the high temperature of thermal processing, high chemical activity, and limited cold deformation ability of titanium alloys. In recent years, the hydrogen treatment technology of titanium alloys developed in recent years, that is, proper hydrogen infiltration in titanium alloys to generate hydrogen-induced thermoplasticity, so that titanium alloys reduce the thermal deformation resistance of titanium alloys, thereby improving the hot workability of titanium alloys. High temperature alloys are above 650°C. Alloys with certain mechanical properties, oxidation resistance and corrosion resistance at a certain temperature. At present, nickel-based, iron-based and cobalt-based are commonly used.
The general term for base superalloys with a higher degree of alloying, also known as superalloys in the United Kingdom and the United States. In current aircraft engines, the use of superalloys accounts for 40% to 60% of the total engine materials.
In addition, the application of superalloys in the civilian field is gradually expanding, such as high-temperature components of industrial gas turbines for power generation, automotive valves, petrochemical equipment, marine diesel engines, etc. All show the application potential of superalloys.
The commonly used diffusion bonding technology of titanium alloys and superalloys is usually carried out at high temperatures, usually higher than 850 ° C, which requires more stringent equipment, and is prone to internal stress and high brittleness.
Intermetallic compounds, and a slight application of pressure can cause severe deformation of titanium alloys, and can no longer be used, because the study of low-temperature diffusion bonding has far-reaching significance. The low-temperature connection of titanium hydride alloy and high-temperature alloy is then applied to the connection of high-temperature components such as high-temperature thrust chamber nozzles, which can give full play to the advantages of the two materials.