With the mature development of investment casting technology, casting superalloys have achieved long-term development. Investment casting is a near net forming process. Its castings are precise and complex, close to the final shape of the parts, and can be used without processing or with little processing [8]. Investment casting can significantly reduce the amount of forming surface and mating surface processing of the product, saving processing time and the consumption of prop materials. At the same time, it can cast castings with complex shapes, and can also cast castings with a wall thickness of 0.5 mm and a weight as small as 1 g. It is also possible to cast combined, integral castings instead of welding or assembling several parts. part.
The application of directional solidification and single crystal vanes is an important symbol of advanced engines at home and abroad. Therefore, from the mid-1960s, China began to study directional solidification technology. The so-called directional solidification is to control the solidification process of the alloy so that it can be produced in a certain direction, and the final structure has no transverse grain boundary, and thus has excellent mechanical properties. Taking the Aviation Materials Institute as a representative, from the retrofitting equipment to the introduction of equipment, the successful power reduction method and the mold-moving orientation technology were developed. The research in the early 1980s succeeded in developing and perfecting the unidirectional unidirectional solidification technology with Chinese characteristics.
As the leading direction of casting aluminum alloys, single crystal superalloys have always been the focus of research. Because there is no grain boundary, it has excellent performance and can withstand higher temperatures and harsher environments. Domestically, in the field of single crystals, a dual orientation control method has been developed that is different from similar foreign technologies. For this purpose, a special spiral crystal selector has been designed and good results have been obtained.
