High-temperature alloys help gas turbines improve power generation efficiency

As a core equipment for efficient power generation, the efficiency improvement and service stability of gas turbines are directly related to energy utilization efficiency and power generation costs. The temperature before the turbine is a key indicator determining the efficiency of gas turbines. For every 100°C increase in temperature, fuel efficiency can be improved by about 5%. This breakthrough is highly dependent on materials capable of withstanding extreme high temperatures, high pressures, and corrosive conditions. High-temperature alloys, with their excellent high-temperature strength, oxidation resistance, and creep resistance, have become the core materials for breaking through the efficiency bottleneck of gas turbines, providing a solid guarantee for energy conservation and efficiency improvement in the power industry.
Nickel-based superalloys are the mainstream choice for hot-end components of gas turbines, achieving synergistic improvements in performance and efficiency through precise composition control and process optimization. In core components such as turbine blades and guide vanes, single-crystal nickel-based superalloys, with their structural advantage of eliminating grain boundaries, significantly enhance creep rupture strength and high-temperature stability, enabling them to withstand extreme environments above 1100°C. For example, CMSX-4 single-crystal alloy, without the need for grain boundary strengthening elements, significantly improves melting point and high-temperature performance. When applied to first-stage turbine blades, it allows gas turbines to operate at higher temperature ranges for longer periods, pushing net efficiency to over 45%, and achieving an 8%-10% efficiency improvement compared to traditional alloy components.
The integration of advanced casting processes with high-temperature alloys further unlocks the efficiency potential of gas turbines. Directional solidification technology eliminates transverse grain boundaries and reduces microporosity by forming columnar grains parallel to the stress direction, significantly enhancing the creep rupture strength and low-cycle fatigue life of the alloy. It is widely used in second- and third-stage turbine blades. The CM 247 LC directional solidification alloy maintains high strength while optimizing processing performance, adapts to the complex component forming requirements of gas turbines, effectively reduces unplanned downtime caused by component failure, and indirectly improves power generation efficiency and equipment utilization.
The innovative application of weldable high-temperature alloys provides a new path for gas turbine maintenance and efficiency maintenance. CM 939 weldable alloy, through optimizing the composition ratio, reducing the content of brittle phases and improving purity, significantly improves ductility and weldability while maintaining similar strength to traditional IN939 alloy. It can be used for components such as combustion chambers and turbine casings. Its welding repair has no risk of cracking in the heat-affected zone, which can extend the service life of components by more than 3 times, reduce replacement costs and downtime, ensure long-term stable operation of gas turbines, and maintain efficient power generation.
The research and development of new high-temperature alloys continue to break through the efficiency ceiling. The chromium-molybdenum-silicon ternary alloy developed in Germany has a melting point of up to 2000℃ and good ductility, solving the pain point of traditional refractory metals being brittle at room temperature and providing new possibilities for increasing the temperature of gas turbines. If such alloys are applied to hot-end components, it is expected to push the net efficiency of gas turbines to exceed 50%, significantly reducing fuel consumption and carbon emissions. In the future, with the deep integration of powder metallurgy, coating technology, and alloy composition, high-temperature alloys will achieve breakthroughs in higher temperature and longer lifespan dimensions, injecting core impetus into the upgrading of gas turbine power generation towards high efficiency and low carbon.