The effect of YAG laser surface treatment on corrosion resistance of Al₁₈B₄O₃₃w/2024Al composite

As a new material, aluminum borate whisker reinforced aluminum composite has been considered for a wide range applications. However, addition of reinforcements to aluminum will change the corrosion behavior significantly. A pulsed YAG laser installation was used to produce surface treatment on Al₁₈B₄O₃₃w/2024Al composite. Electrochemical method was used to study the corrosion resistance in 3.5% sodium chloride (NaCl) solution. The crystalline phases of the composites with and without laser surface treatment were analyzed using X-ray diffraction (XRD) measurement technique. The cross-section morphologies of the laser-treated composite were characterized by scanning electron microscope (SEM). Polarization experiments showed that the sensibility to pitting corrosion for the laser treated specimen was greatly lower than that of the untreated specimen. The reduction of reinforcement Al₁₈B₄O₃₃ whisker and intermetallics CuAl₂ on the surface of the laser-treated composite along with the formation of the homogeneous and defect free microstructure in the laser-modified layer led to improvement on the corrosion resistance of the laser-treated composite.