Rapid Nitriding of Titanium Alloy with Fine Grains at Room Temperature

Multifunctional surfaces are required to design safe engineering products for human lives. Heating in a nitrogen atmosphere (nitriding) improves the tribological properties but reduces the strength of titanium (Ti) alloys owing to grain coarsening. A rapid nitriding method for Ti alloys forms the nitrided layer on the surface of a Ti alloy by bombarding with commercially pure Ti fine particles with a nitrided phase at room temperature within a short period. Furthermore, fine grains of Ti alloy are formed in the nitrided layer because of the impact of the Ti particles. These results reveal that this room‐temperature method resolves the trade‐off between the rapid formation of a nitrided layer and the suppression of grain coarsening for Ti alloys. The mechanical and tribological properties are important for titanium alloys, which are used as biomaterials. Inspiration is taken from the transfer of fine particles to achieve rapid nitriding without heating. The developed room‐temperature methods result in the formation of a nitrided layer within a short period. The proposed method has the potential to improve various properties in other metallic materials.