Role and mechanism of innovative addition process of trace nano-TiCp in microstructure manipulation and significant mechanical properties enhancement of H13 steels

The use of nanoparticles to efficiently manipulate the microstructure of steel and improve its mechanical properties has considerable practical relevance and application value. This study proposes the novel manufacturing process of dispersing nanoparticles within the melt through master alloys and investigates the effect on the microstructure and properties of the TiC-nanoparticle-reinforced H13 steel through this nanoparticles-dispersion process in synergy with the forging and heat treatment. As a consequence of the nanoparticles-dispersion process, the microstructure was significantly refined, the grain size and the length of martensite lath were both reduced, and the precipitates were more homodispersed. The finer microstructures could prevent stress concentration, promote synergy between grains, and mainly induce grain refinement, and second-phase strengthening, resulting in an unprecedented enhancement in strength and toughness. The tensile yield strength, ultimate strength, fracture strain, no-notch, and U-shaped-notch impact toughness in 0.02 wt% TiC-nanoparticle-reinforced H13 were 1453 MPa, 1724 MPa, 13.1%, 376.9 J/cm2, and 36.4 J/cm2, which were 8.1%, 12.1%, 12.9%, 17.5%, and 23.8% higher than those of H13. This research overcomes a critical technology bottleneck in the preparation of nanoparticle-strengthened steel and offers a novel approach to manufacturing high-performance steel.