1Professor School of Metallurgy and Materials Eng.
2School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran
چکیده
Aluminium and aluminium alloys, and copper and copper alloys are two important class of metallic materials with the basic fcc crystal structure but different stacking fault energy (SFE). These metallic materials play an important role in the industrial components. Therefore, the mechanical properties improvement of these materials especially by severe plastic deformation received much attention. The response of Aluminium 1100 and pure copper to the ECAP-Conform as a continuous severe plastic deformation method are compared from the stand points of microstructural variations. Microstructural variations were examined using scanning electron microscopy equipped with electron back scatter diffraction (EBSD). It is shown that Al as a high SFE material showed dynamic recovery before last step of ECAP-Conform and partial continuous dynamic recrystallization at the final step of ECAP-Conform led to fine grains. But in the case of pure copper, some kind of grain refinement due to appearance of mechanical twins occurred before last stage of ECAP-Conform and discontinuous recrystallization observed in the microstructure of the final stage of ECAP-Conform that produced ultrafine grain structure. Different method of grain refinement in two metals with the basic fcc crystal structure but different SFE as the response to the severe plastic deformation are interesting due to the various engaged refinement mechanisms.
