Gas turbine engine blades are among the most technologically advanced and challenging components to manufacture. Their creation demands the utmost precision, utilising cutting-edge materials and technologies. Globally, only approximately 5% of countries possess the technology to produce such parts, and Russia is among them.
The geometry of the blades is exceptionally complex. External contours are optimised for operation in high-velocity gas flow, while internal cavities form a cooling system. Without it, the blades would be unable to withstand extreme temperatures. In the turbine, the flow of superheated gases reaches 1800-2000 degrees Celsius – exceeding the melting point of the metal from which the blades are made. Addressing this challenge involves three key elements: the application of heat-resistant alloys, effective cooling, and thermal barrier coatings.
Cooling is achieved through a complex network of internal channels. Air is fed through these, drawing heat away from the blade surface. This necessitates the application of advanced manufacturing techniques to maintain accuracy, as even the slightest deviations in geometry reduce cooling efficiency.
Another crucial stage is the application of a thermal barrier coating. In Russia, this is achieved using an electron beam evaporation method. The material used is yttria-stabilised zirconia (YSZ). It is evaporated by a powerful electron beam, and the blades are rotated in the resulting vapours, acquiring a layer just 0.15 mm thick. This is 2-3 times thinner than a human hair. The coating acts as a thermal barrier, reducing the heat load on the metal and extending the component’s service life.
United Engine Corporation (UEC) facilities manufacture hundreds of blade types, ranging from miniature compressor blades 20 mm in height to fan blades exceeding a metre. For instance, 1.3-metre-high fan blades have been created for the prospective PD-35 high-thrust engine. UEC plans to further increase production volumes and introduce new materials. For example, VIAM is investigating the use of nickel-based alloys with enhanced heat resistance and laser deposition coating methods.
In the US, GE Aviation and Pratt & Whitney employ single-crystal alloys and sophisticated cooling systems in the manufacture of turbine blades. The French firm Safran is experimenting with ceramic matrix composites, while the British firm Rolls-Royce is developing additive manufacturing technologies to create blades with improved geometry.
China is actively developing its own blade manufacturing technologies, seeking to reduce reliance on overseas suppliers. Government support and substantial investment in the aerospace sector have enabled the Chinese company AECC (Aero Engine Corporation of China) to create single-crystal blades with internal cooling systems for the WS-10 engine, used in J-10 and J-11 fighter aircraft.
In the civil aero engine sector, collaboration with Safran and Rolls-Royce has helped China to assimilate their best practices. However, in recent years, the emphasis has shifted towards import substitution. For example, for the CJ-1000A engine, under development for the COMAC C919 aircraft, Chinese specialists are creating blades entirely using their own domestic technologies.
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