The working environment of aircraft engines is extremely harsh. Under extreme working conditions such as high temperature and cold, strict requirements are put forward for the service life of high isothermal alloy castings such as turbine blades, blade discs, and turbine casings. If traditional investment casting technology is used, it will lead to columnar or dendritic crystals in the produced castings, with an average grain size exceeding 4 millimeters, coarse grains, and differences in microstructure, The performance of different parts may vary. If high-temperature alloys are produced through such technology, it may lead to fatigue cracks in the castings during use, shorten the service life. The application of equiaxed grain precision casting technology can change the current situation, especially fine grain casting technology, which can effectively control the traditional investment casting process, strengthen the mechanism of alloy nucleation, and form a higher number of crystalline cores, It has a suppressive effect on grain growth and obtains equiaxed crystal castings with an average grain size within 1.6mm and high uniformity, which comply with relevant standards.

In the mid-1970s, USA began using high-temperature alloy fine-grained casting technology to produce aircraft engine alloy turbine products in the form of thermal runaway. The material casting superheat was maintained within 27 ℃, and the average grain size was controlled at around 0.51mm in diameter. Compared with traditional investment casting technology, fine-grained casting extended the casting life by more than 75%.

Due to the influence of Germany's research on various types of metal compounds in alloy refinement in the 1980s, Northwestern Polytechnical University of China also began to study metal compound refining agents, forming the effect of alloy refinement. It was found that using metal compound refining agents not only ensures microstructure refinement, but also enhances the refinement effect of carbides, increases the number of equiaxed grains, and reduces the number and size of dendrites, Enhance the yield and tensile strength of alloys under different temperature conditions. The application of this method belongs to the chemical grain refinement technology, and its easy to operate characteristics make it widely used in the production process of surface refinement castings. However, due to the significant influence of temperature during the melting and pouring process on the chemical grain refinement technology, the number of reaction nucleation is less when the temperature is lower, and the nucleation is remelted in the melt when the temperature is too high, resulting in poor final refinement effect. The melting and casting process of high-temperature alloys has certain complexity characteristics. The melting point of high-temperature alloys is generally above 1300 ℃, and overheating treatment is required before casting. Under high temperature conditions, many additives will decompose or directly fuse with the melt, which cannot retain the formation of nucleation substrates. This results in certain limitations on the use of additive materials during production, So in the future production process, it is necessary to scientifically use chemical additives in conjunction with the situation of high-temperature alloys.