Preferred orientation formation in surface layer of aluminum sheet subjected to friction roll surface processing and temperature gradient annealing

Abstract

Preferred orientation formation in surface layer of aluminum sheet subjected to friction roll surface processing (FRSP) and temperature gradient annealing has been investigated by SEM/EBSD analysis. FRSP imposed severe shear strain in the surface layer of the aluminum sheet, where the indentation was selected as 0.1mm and the feeding speed was set as 0.3mm/s. The annealing with steep temperature gradient in longitudinal direction was applied to the small specimen of 12mm long, 10mm wide and 1mm thick, which made microstructural evolution concentrated to the nearest layer to the surface. Shear strain more than 10 was imposed at a site of 14μm beneath the surface. The temperature gradient more than 20K/mm was attained even for aluminum which has high thermal conductivity. The {100} pole of ND/TD (FRSP plane/FRSP direction) FRSPed specimen showed very weak intensity of <001>//ND while the {111} pole implies <110>//TD. In contrast, the shear texture component {111}<110> mainly evolved in the specimen subjected to FRSP and the ordinary annealing. Evolution of the component {111}<110> after the temperature gradient annealing were compared with that after the ordinary annealing in consideration of stored strain energy in each crystallographic orientation.