Iron-rich layer introduced by SMAT and its effect on corrosion resistance and wear behavior of 2024 Al alloy

• Published in: Materials chemistry and physics Vol. 126; no. 1; pp. 301 - 309
• Main Authors: Wen, Lei, Wang, Yaming, Zhou, Y., Guo, L.X., Ouyang, J.H.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.03.2011
• Subjects: Aluminum; Aluminum alloy; Aluminum base alloys; Corrosion resistance; Electrochemical impedance spectroscopy; Electrochemical techniques; Grain size; Nanocrystals; Nanostructures; Scanning electron microscopy; Surface mechanical attrition treatment; Wear; Wear resistance; Surface mechanical attrition treatment; Electrochemical techniques; Nanostructures; Wear; Aluminum alloy
• ISSN: 0254-0584; 1879-3312
• DOI: 10.1016/j.matchemphys.2010.11.022

▶ A nanocrystalline layer with an average grain size of 55 nm was produced at the surface of Al alloy by SMAT process. ▶ A 5 μm thick surface layer containing Fe, the grain size of which was in nanometer scale, was introduced into the top layer of Al nanocrystalline surface. ▶ The iron-rich layer led to the diminution of corrosion resistance of 2024 Al alloy, while the wear resistance was improved due to the beneficial combination of refined grains, increased hardness and lubrication effect of iron-rich layer. The nanocrystalline microstructure of the surface of 2024 Al alloy induced by surface mechanical attrition treatment (SMAT) was determined by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The corrosion behavior of 2024 Al alloy after SMAT was investigated by potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS). A pin-on-disk tribometer was used to determine the tribological properties of nanocrystalline layer under dry sliding conditions. The results demonstrated that the Al nanocrystalline layer with an average grain size of 55 nm, when treated for 30 min, was produced at the surface of Al alloy. However, a 5 μm thick surface layer containing Fe, the grain size of which was in nanometer scale, was also introduced into the top layer of Al nanocrystalline surface. The iron-rich layer led to the diminution of corrosion resistance of 2024 Al alloy, while the wear resistance was improved due to the beneficial combination of refined grains, increased hardness and lubrication effect of iron-rich layer.