| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1616716 | Journal of Alloys and Compounds | 2011 | 7 Pages |
Surface distinct deformed layers with thicknesses up to 150 μm, with grain size in the top most surface is in the nanometer scale, were produced on AZ91D magnesium alloy using surface mechanical attrition treatment (SMAT). Effects of different ball size on the properties of the SMATed samples were investigated. The microstructural, grain size, hardness and roughness features of the treated surfaces were characterized using optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD), micro-indenter and digital roughness meter, respectively. Corrosion behavior of the samples was evaluated using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. It is found that the ball diameter does not have a significant effect on the top surface grain size, but the thickness of the deformed layer increases with increase of ball size, from 50 μm for 2 mm balls to 150 μm for 5 mm balls. For all of the SMATed samples, the top surface microhardness value increased significantly and did not show any obvious change for samples treated with different balls. Corrosion studies show that the corrosion resistance of the sample treated with 2 mm balls is higher than that of those treated with 3 mm and 5 mm balls. This can be mainly attributed to the surface roughness and defects density of the samples, which are higher for the SMATed samples with 3 mm and 5 mm balls compared with that of sample SMATed with 2 mm balls.
► Nanostructured surface layers were produced on AZ91D magnesium alloy by using SMAT. ► Thickness of the deformed layer increased with increasing of the balls size. ► Top surface microhardness for all of the SMATed samples increased significantly. ► SMAT increased the surface roughness; increase in balls diameter increased the roughness. ► SMAT using 2 mm balls increased the corrosion resistance significantly.
