Effect of scanning speeds on electrochemical corrosion resistance of laser cladding TC4 alloy

In order to study the effect of scanning speed on the electrochemical corrosion resistance of laser cladding TC4 alloy in artificial seawater, the x-ray diffraction analysis, microstructure of cross-section, microhardness variation, and impedance spectrum have been studied in comparison with the TC4 titanium alloy. The results show that the main phase of cladding coating is alpha-Ti, and the change of scanning speed has no obvious effect on it; therefore, the supersaturated alpha-Ti solid solution is formed, and the acicular alpha' martensite is obtained. As the scanning speed increases, the microstructure of cladding coating is orthogonal basket-weave, the crystal surface spacing decreases, and the average microhardness of laser cladding TC4 alloy slightly increases. When the scanning speed increases to 10 mm/s, the microhardness is about 14.71% higher than that of the substrate, and the electrochemical corrosion resistance of laser cladding TC4 alloy is also improved, which is about 2.48 times more than the substrate. Grain refinement has a great effect on enhancing the anti-electrochemical corrosion.