Thermal Stability of Ultrafine Grains in Al-Fe-Mn-Si Foils Prepared by ARB and Subsequent Rolling

摘要: Accumulative Roll Bonding (ARB) is a severe plastic deformation process that allows producing ultrafine-grained materials (UFG). UFG sheets exhibit enhanced strength and very fine grain structure. Foils used as fins in heat exchangers have to be thin but must high combined with relatively formability. Thus, produced using ARB may fulfil the exacting requirements on foil properties for such applications. The thermal stability of Al-Fe- Mn-Si foils subsequent cold rolling was studied compared conventionally rolled (CCR) counterparts. assessed by isothermal annealing temperature range from 200 450 °C. Electron back scatter diffraction scanning electron microscope transmission microscopy examinations microstructure deformed annealed states allowed monitoring structural changes. magnitude mechanical changes due evaluated microhardness measurements. Significant hardness increase observed after at °C only samples assigned an annealing-induced hardening. CCR exhibits higher non-recrystallized fraction smaller mean lamellae boundary spacing interval 200-250 than foils. results identical values fully recrystallized all foils, regardless method their manufacturing. However, show refined substructure counterparts continuous recrystallization occurring