超声喷丸对6061铝合金耐腐蚀性能的影响

Effect of Ultrasonic Shot Peening on Corrosion Resistance of 6061 Aluminium Alloy

采用维氏显微硬度仪和三维形貌仪测量喷丸前后试样硬度、粗糙度及表面形貌;使用CHI660E电化学工作站来测量动电位极化曲线;采用扫描电子显微镜(SEM)观察电化学腐蚀后的试样微观形貌,探讨经过超声喷丸处理形成的表面组织细化对6061-T6铝合金耐腐蚀性能的影响。研究结果表明:弹丸对材料表面反复撞击,诱发了严重的塑性变形,铝合金表层硬度增加,晶粒尺寸在一定的深度范围内得到了细化,晶界增多阻碍内部裂纹的产生,从而促进材料钝化膜的产生,抑制了腐蚀液对金属的腐蚀,进而减小了腐蚀电流密度和速率,改善了材料的耐腐蚀性能。

A Vickers microhardness tester and a three-dimensional morphometry were used to measure the hardness,roughness,and surface morphology of the specimens before and after shot peening;an electrochemical workstation model CHI660E was used to measure the kinetic potential polarisation curve;scanning electron microscopy(SEM) was used to observe the microscopic morphology of the specimens after electrochemical corrosion.The effect of surface refinement formed by ultrasonic shot peening on the corrosion resistance of 6061-T6 aluminum alloy was investigated.The results show that the repeated impact of the shot on the surface of the material induced severe plastic deformation increased the hardness of the aluminum alloy surface layer,the grain size was refined within a certain depth range,and the increase in grain boundaries prevented the generation of internal cracks to promote the generation of passivation film,which inhibited the corrosion of the metal by the corrosive solution,thus reducing the corrosion current density and rate and improving the corrosion resistance of the material.