Quantitative study on the precipitation behavior of dispersoids in DC-cast AA3003 alloy during heating and homogenization

摘要

The precipitation behavior of dispersoids in DC-cast AA3003 billet during heating and homogenization at 600 ℃ has been studied by means of TEM, electrical conductivity measurement and image analysis. The orientation relationship between the dispersoids and matrix has been determined. The size, size distribution, number density and Mn/Fe ratio of dispersoids, and the area fraction of PFZ have been measured. The evolution of dispersoids during heat treatment is controlled by nucleation, growth, dissolution and coarsening. A method is proposed to measure the volume fraction of dispersoids from TEM images. The volume fraction of dispersoids precipitated during heating measured from TEM images is in good agreement with that calculated from electrical conductivity data.