Measurement of Strain and Lattice Rotation in the Particle Deformation Zone

Abstract

It is known that there is lattice rotation around the particles after deformation, in a so-called Particle Deformation Zone (PDZ), which is thought to be important in randomizing the texture after recrystallization though Particle Stimulated Nucleation (PSN). However, the role of the local distribution of stored energy and its link to local lattice rotation is not well understood, making it impossible to successfully predict PSN efficiency. Here, we present a new method for studying the deformation around particles with the use of Digital Image Correlation (DIC) of High-Resolution Scanning Electron Microscopy (HRSEM) image and Electron BackScatter Diffraction (EBSD) map. Combining these two techniques makes it possible, for the first time, to relate the local deformation fields to remnant changes in local lattice orientation. Initial measurements are made on a model Al-Si alloy deformed in plane-strain condition by channel die compression up to 30%. Our analysis shows that the material deforms heterogeneously with high levels of deformation localized along slip bands. EBSD analysis shows that the lattice distortion in these bands is minimal. The HRDIC analysis clearly shows particles interrupt the slip banding. Local lattice rotation measured by EBSD is considerably less than expected from the measured deformation.