In the quest to enhance the efficiency and longevity of power plants, researchers are delving deep into the microstructure of advanced steels. A recent study published in *Frontiers of Materials & Technologies* (formerly *Frontier Materials & Technologies*) has shed light on the promising potential of a specific type of steel, offering insights that could revolutionize the energy sector.
Valeria V. Osipova, a leading researcher from the National Research Tomsk State University and the Institute of Strength Physics and Materials Science of the Siberian Branch of the Russian Academy of Sciences, has been at the forefront of this investigation. Her team focused on the structural-phase state and microhardness of reduced-activation 12% chromium ferritic-martensitic steel, known as EK-181, after subjecting it to thermomechanical treatments with deformation at high temperatures.
The study revealed that when EK-181 steel undergoes thermomechanical treatments with plastic deformation in the austenitic region at 1000°C and 1100°C, a unique microstructure forms. This microstructure is characterized by martensitic laths, fine plates of cementite, retained austenite, and MX-type carbonitride particles. “The high-temperature tempering at 720°C for one hour leads to the coarsening of structural elements and a reduction in dislocation density,” Osipova explained. “However, the MX carbonitrides exhibit remarkable thermal stability, retaining their sizes even after the tempering process.”
One of the most significant findings was the impact of deformation temperature on the steel’s properties. A decrease in deformation temperature led to an increase in crystal lattice microdistortions and a reduction in coherent scattering regions. This discovery could have profound implications for the energy sector, where the durability and performance of structural materials are paramount.
Compared to traditional heat treatment (THT), the thermomechanical treatments with deformation in the austenitic region ensured a reduction in the average size of prior austenite grains by 2 times, martensitic laths by 1.5 times, and M23C6 particles by 2 times. “The higher dislocation densities and crystal lattice microdistortion values observed after these treatments are crucial for enhancing the steel’s mechanical properties,” Osipova noted.
The microhardness values after thermomechanical treatments and tempering were found to be 10% higher than those achieved after traditional heat treatment. This enhancement in microhardness could translate to improved performance and longevity of components in power plants, potentially reducing maintenance costs and increasing operational efficiency.
The research conducted by Osipova and her team not only advances our understanding of the structural-phase state and microhardness of EK-181 steel but also paves the way for future developments in the field. As the energy sector continues to evolve, the demand for advanced materials that can withstand extreme conditions and deliver superior performance will only grow. This study provides valuable insights that could shape the future of structural materials in power plants, ultimately contributing to a more efficient and sustainable energy landscape.