光斑直径对激光冲击强化铝合金腐蚀性能的影响

Effect of spot diameter on corrosion resistance of aluminum alloy subjected to laser shock peening

为研究不同光斑直径对激光冲击强化6061-T6铝合金电化学腐蚀性能的影响,测量了表面粗糙度和残余应力,进行了截面金相和电化学腐蚀实验。结果表明:激光冲击强化使材料的表层晶粒细化、表面粗糙度增大且产生残余压应力。未冲击试样、2 mm和3 mm光斑直径激光冲击试样的腐蚀电流密度分别为:154.5μA/cm^(2)、14.70μA/cm^(2)和11.17μA/cm^(2),激光冲击强化有效地提高了材料的耐腐蚀性能。2 mm光斑直径激光冲击试样相比于3 mm光斑直径激光冲击试样拥有较差的表面形貌,其耐腐蚀性能较差。

In order to investigate the effect of different spot diameters on the electrochemical corrosion resistance of 6061-T6 aluminum alloy subjected to laser shock peening,the surface roughness and residual stress of the alloy were measured. The cross-sectional metallographic and electrochemical corrosion experiments were carried out. Corroded specimens were observed and analyzed by scanning electron microscope(SEM) and energy dispersive spectroscopy(EDS). Results show that laser shock peening refines the surface grains of 6061-T6 alloy,increases the surface roughness and generates a compressive residual stress. The corrosion current densities of the untreated specimen,treated specimens with 2 mm and 3 mm spot diameters were 154.5 μA/cm^(2),14.70 μA/cm^(2) and 11.17 μA/cm^(2),respectively,indicating that laser shock peening effectively improves the corrosion resistance. The treated specimen with 2 mm spot diameter had worse surface topographies than that of the treated specimen with 3 mm spot diameter,resulting in the lower corrosion resistance.