On the Hall-Petch relationship in a nanostructured Al-Cu alloy

Mechanical properties of bulk nanocrystalline Al-4Cu alloys with grain sizes from 47 to 105nm, synthesized by mechanically alloying followed by vacuum hot pressing at different temperatures, were analysed through Hall-Petch relation. Hall-Petch analysis revealed a high frictional stress (170MPa) and a high positive slope (0.13 MPa m) as compared to pure Al, which has a frictional stress (15-30MPa) and a slope (0.06-0.09 MPa m). From a detailed evaluation of different strengthening mechanisms it is inferred that the Al2Cu precipitates and oxide particles are the likely reason for such high values of frictional stress and slope. © 2010 Elsevier B.V.