Experimental studies of prototype models of bimetallic blisks of a high-temperature turbine with cooled blades for advanced gas turbine engines

The traditional approach to designing turbine blisks based on the application of disk-blade pawl-coupling does not allow improving the design from the point of view of increasing the service life, reducing the wheel mass and improving the engine efficiency on the whole. This problem can be solved by using dissimilar materials in the integrated bimetallic wheel (blisk). Bimetallic blisk prototype models of a high-temperature turbine have been produced for strength durability research. The bimetallic blisk prototype model consists of one monocrystal cooled blade and a granulated Ni-based disk part. These elements are connected by the hot isostatic pressing (HIP) method. Capsular equipment is designed for producing the prototypes. It ensures the air tightness of the zone of joining of the blisk elements and preservation of the cooling lines in the blades during the HIP process.  Investigations of micro- and macrostructures of prototype joining zones have been carried out. High-cycle fatigue tests of bimetallic blisk prototype models have been carried out. It has been found that fatigue cracks originate in the blade material, whereas the zone of diffusion bonding of the two alloys in test conditions proved to be stronger than the blade material.