Grain size dependence of slip band length with plastic deformation in aluminum alloy

Slip bands formed after small additional deformation (Δε=0.5%), are observed as straight lines in the lower strain region and at that strain region the stress-strain curve can be approximated by the Ludwik equation. The measurements of slip band length have been made in this strain region for various grain sizes of aluminum and Al-5% Mg alloy. The slip band length decreases with strain. At constant strain, the larger the grain size is, the longer is the slip band length in both aluminum and Al-5%Mg alloy specimens. The linear relation between flow stress and inverse square root of grain size is not observed at higher strain region. On the other hand, linear relation between flow stress and inverse square root of slip band length can be seen at any strains. At constant grain size, linear relations are also observed with decreasing strain between flow stress and inverse square root of slip band length, and the slopes of those linear lines are almost the same, irrespectively of the grain size. Slip band length-strain curves calculated from the Ludwik equation are in good agreement with the experimental stress-strain curves.