In a groundbreaking development for the energy sector, researchers have discovered a novel method to significantly enhance the mechanical properties and corrosion resistance of stainless steel used in additive manufacturing. This innovation, published in the journal “Virtual and Physical Prototyping,” could revolutionize the production of critical components for extreme environments, such as nuclear reactors and marine equipment.
The study, led by Zibin Liu from the School of Mechanical and Automotive Engineering at South China University of Technology, focuses on the laser powder bed fusion (LPBF) process. By leveraging laser-gas-powder synergy, Liu and his team successfully generated TiO₂ and TiN nanoparticles through in-situ Ti-O-N chemical reactions. These nanoparticles play a dual role: refining grains and suppressing sensitisation, which in turn boosts both mechanical strength and corrosion resistance.
“Our approach not only refines the grain size from 16.5 μm to 0.68 μm but also increases the yield strength from 537 MPa to over 1 GPa, all while maintaining an impressive elongation of 31.4%,” explains Liu. This remarkable improvement in mechanical properties is complemented by a significant reduction in corrosion current density, dropping from 3.122 × 10−⁷ A·cm−² to 5.068 × 10−⁸ A·cm−². The suppression of sensitisation, achieved through the adsorption of impurity elements by titanium, is a key factor in this enhancement.
One of the most innovative aspects of this research is the use of an N2 atmosphere, which ensures the complete conversion of residual titanium to TiN. This prevents titanium segregation and promotes microstructural homogeneity, further enhancing the material’s performance.
The implications for the energy sector are profound. Stainless steel components that can withstand extreme environments are crucial for the safety and efficiency of nuclear reactors and marine equipment. The ability to produce such components through additive manufacturing not only improves their performance but also offers greater design flexibility and cost savings.
“This research opens up new possibilities for the energy sector,” says Liu. “By improving the mechanical and corrosion properties of stainless steel, we can enhance the reliability and longevity of critical components, ultimately leading to safer and more efficient energy production.”
As the energy sector continues to evolve, the demand for advanced materials that can withstand extreme conditions will only grow. This research by Liu and his team represents a significant step forward in meeting that demand, paving the way for future developments in additive manufacturing and materials science.