Due to the relatively complex structure of gas turbines, the temperature and force conditions of various parts are quite different, so the requirements and selection of materials are different.

1. High temperature alloy for combustion chamber
The mechanical stress of the combustion chamber is relatively small, but the thermal stress is relatively large. The main requirements for the material are: high temperature oxidation resistance and gas corrosion resistance; sufficient instantaneous and lasting strength; good cold and hot fatigue performance, good process plasticity (Durability, bending performance) and welding performance; the alloy is stable for a long time at working temperature.

2. High temperature alloy for guide vane
The first stage of the guide vane is one of the most thermally impacted parts on the turbine engine. But because it is stationary, the mechanical load on it is not large. Usually due to the distortion caused by stress, cracks caused by drastic temperature changes, and burns caused by over-combustion, the guide vanes often fail during operation. According to the working conditions of the guide vane, the material is required to have the following properties: sufficient permanent strength and good thermal fatigue performance; high resistance to oxidation and corrosion; if cast alloys are used, good casting performance is required.

3. High temperature alloys for turbine moving blades
Turbine working blades are one of the most critical components on turbine engines. Although the operating temperature is lower than that of the guide vane, the force is large and complex, and the working conditions are harsh. Therefore, the turbine blade materials require high oxidation and corrosion resistance; high creep and long-lasting fracture resistance; good The mechanical fatigue and thermal fatigue performance and good high temperature and medium temperature comprehensive performance.

4. High temperature alloy for turbine disc
Turbine disc is unevenly heated during operation, and the rim part of the disc bears a higher temperature than the center part, resulting in great thermal stress. The tenon tooth part bears the greatest centrifugal force, and the stress is more complicated. For this reason, the requirements for turbine disk materials are: alloys should have high yield strength and creep strength; good thermal and mechanical fatigue properties; a small linear expansion coefficient, no notch sensitivity, and high low-cycle fatigue properties.

The development trend and new technology of superalloy
In order to meet the needs of the new generation of gas turbines for high-performance materials, in addition to the continued development of directional solidification casting technology and single crystal casting technology, powdered superalloy technology and new high-temperature oxidation-resistant and gas-erosion-resistant protective coating technology have also been obtained. Wide range of applications. Powder superalloy technology FGH51 powder superalloy is a phase precipitation strengthened nickel-based superalloy prepared by powder metallurgy technology. The volume fraction of the γ phase of the alloy is about 25%-50%, and the atomic fraction of its forming elements is about 50%. The manufacturing process of the alloy discs is to use vacuum induction melting to prepare the master alloy, and then atomize to prepare the pre-alloyed powder, and then make the part blank. Compared with similar cast and forged high-temperature alloys, it has the advantages of uniform structure, fine grains, high yield and good fatigue performance. It is a high-temperature alloy with the highest level of strength under the current 650°C working condition. This kind of high temperature gold is mainly used for rotating parts of high-performance engines, such as turbine discs and bearing rings.