Papers by Author: Shamil Mukhtarov

Abstract: It is known that different parts of the gas turbine engine discs are operated at different temperature and load. Therefore, it is advisable to make such components out of nickel-based superalloys with a regulated structure that provides them the best operational properties. It is important to know the thermomechanical treatment for their processing to form such structures. Research of the deformation behavior and the microstructure evolution of nickel-based superalloys were carried out on small specimens. The accumulated strains and the stress distribution in specimens were determined during simulation. It is possible to predict structure formation on the basis of a deflected mode. Verification was carried out by isothermal upsetting of specimens out of superalloys at the temperature and strain rates determined by simulation. Thermomechanical treatments of the superalloys for different microstructure formation were defined. The features of the microstructure formation are shown depending on the chemical and phase composition of the alloys. Hot deformation of the ATI Allvac 718Plus superalloy leads to dissolution of the gamma prime phase that facilitates the deformation capacity. Increasing the alloyage of superalloys, including rhenium, leads to formation of a necklace structure instead of a homogeneous fine-grained structure for less alloyed superalloys at the same strain.

Abstract: Heat-resistant alloys are the basic material of gas turbine engine (GTE) design. Fine-grained structure in these alloys can be formed by isothermal forging and then different axisymmetric GTE components as wheels, shafts, rings can be superplastic roll formed. Examples of the superplastic and isothermal deformation use for manufacturing components out of superalloys and steels for critical applications are given. The possibility of roll forming parts as rings with a diameter up to 800 mm and as flange - cone with a diameter up to 600 mm out of superalloys (Inconel 718, EK79, EP741NP), accordingly, on SRZHD-800 and modified PNC-600 mills were showed. The macrostructure investigations of the components after the roll forming showed that the homogeneous structure was formed. The microstructure at the flange portion was fine-grained and at membrane zone was coarse-grained. Cone part was roll formed at isothermal condition from pre-stamped chromium martensitic steel sheet. Manufacturing technology of roll forming was tested by computer and physical simulation. Service properties of components were obtained by subsequent heat treatment. The effectiveness of the technology associated with increased service properties of components and decreases the labor content by automated equipment.