Effect of Nanocrystalline Surface and Iron-containing Layer Obtained by SMAT on Tribological Properties of 2024 Al Alloy

The pure and Fe-containing nanocrystalline layers were fabricated on the surface of 2024 Al alloy by surface mechanical attrition treatment (SMAT) using ceramic balls and steel balls, respectively. The friction and wear properties of 2024 Al alloy before and after SMAT were investigated by sliding against a GCr15 steel ball of 5 mm in diameter at a load of 1.5 N. The results demonstrate that the surface nanocrystalline layers with average grain sizes of 49.2 and 52.1 nm can be obtained by using ceramic balls and steel balls, respectively, when treated for 30 min. Moreover, a 5 μm thick surface layer containing Fe is also introduced into the Al nanocrystalline surface when treated using steel balls. The wear resistance of 2024 Al alloy is improved due to the combination of grain refinement, increased hardness and lubrication effect of iron-containing layer.