The effect of laser shock peening on the microstructure and wear resistance of micro-arc oxidation coatings on TC4 alloy

Laser shock peening (LSP) was used to prepare a fine-grained transition layer on the surface of titanium alloy (TC4), followed by micro-arc oxidation (MAO) to prepare composite coatings. The influence of LSP on the microstructure, phase structure, adhesion, microhardness, corrosion resistance, and wear resistance of the MAO coatings was studied. The results showed that, after LSP treatment, the diffraction peaks of TC4 became wider, the surface grains were significantly refined, and a high-density dislocation was introduced on the TC4 surface forming a nano-crystal cluster. Compared with the MAO coating, the LSP-MAO composite coating had a smaller pore size, increased coating thickness, microhardness, and depth of strengthening layer. The adhesion, corrosion resistance, and wear resistance of the LSP-MAO coating were better than those of the MAO coating.