CHARACTERIZATION OF THE MORPHOLOGICAL AND LATTICE ORIENTATIONAL MICROSTRUCTURE OF AS-CAST ALUMINUM INGOT

The morphological and lattice orientational microstructure of commercial-purity aluminum ingot (1100 series) is investigated by section analysis and individual measurements of crystallite orientation from electron backscattering diffraction (EBD). These measurements render possible the determination of the sectional grain-area distribution, the number-of-sides per grain section distribution, the mean grain-interception length, the orientation distribution function, and the nearest-neighbor orientation coherence function. It is found that the morphological measures of the aluminum ingot are consistent with predictions based upon the classical Johnson-Mehl model. A small anisotropy of grain shape is observed, with the grains exhibiting a 17 pct larger dimension in the axial direction of the ingot compared with radial and hoop directions. The orientational measures indicate that the ingot has a random texture with random spatial orientation coherence relationships. © 1990 The Metallurgical of Society of AIME.