Improving properties of spring steel through nano-particles alloying

The main challenge in realizing the immense potential of nano-engineered steels is to manufacture large components and quantities at low costs, where homogeneous dispersion of ceramic nano-particles in molten metals is extremely hard to achieve. Therefore, the aim of the present work was to investigate the potential of different nano-particles as alloying elements in the conventional liquid metal casting process and to define their effect on the tensile properties, fracture toughness and fatigue resistance of the spring steel. Results of this investigation indicate that nano-particles reinforcement of spring steel is feasible even by using simple liquid metal casting routes, with the nano-particles type and size having important impact. In the case of larger Al2O3 nano-particles with the highest stability tensile strength of spring steel was improved for up to 10%, while finer and more uniform distribution combined with local reinforcement of the steel matrix in the case of C-nanotubes lead to better fracture toughness and fatigue properties.