Rapid Nitriding of Titanium Alloy with Fine Grains at Room Temperature

Abstract 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.