Slip band behavior at early stage of plastic deformation in polycrystalline aluminum

Abstract

A polycrystalline aluminum with the average grain size of 120μm was deformed in tension mode to 0.01% strain. The behavior of slip bands formed on each grain surface was investigated by optical microscopy as well as crystallographic orientation determined by SEM-ECP method. Some grains in which secondary slip systems had been activated were observed at this stage of plastic deformation. None of elastic strain incompatibility, transmission factor N_ij and plastic strain incompatibility could explain the secondary slip systems becoming active in such grains. When the secondary slip system produced more similar shape change to that of the surrounding grains than the primary slip system did, the secondary slip system was understood to become preferentially active, taking account of the two-dimensional surface shape change after small plastic deformation.