Materials Science Forum, Vol.519-521, 1227-1232, 2006
Accumulative roll bonding of AA8006, AA8011 and AA5754 sheets
Accumulative Roll Bonding (ARB) is a technique of grain refinement by severe plastic deformation, which involves multiple repetitions of surface treatment, stacking, rolling, and cutting. The rolling with 50% reduction in thickness bonds the sheets. After several cycles, ultrafine-grained (UFG) materials are produced. Since ARB enables the production of large amounts of UFG materials, its adoption into industrial practice is favoured. ARB has been successfully used for preparation of UFG sheets from different ingot cast aluminium alloys. Twin-roll casting (TRC) is a cost and energy effective method for manufacturing aluminium sheets. Fine particles and small grain size are intrinsic for TRC sheets making them good starting materials for ARB. The paper presents the results of a research aimed at investigating the feasibility of ARB processing of three TRC alloys, AA8006, AA8011 and AA5754, at ambient temperature. The microstructure and properties of the ARB were investigated by means of light and transmission electron microscopy and hardness measurements. AA8006 specimens were ARB processed without any problems. Sound sheets of AA8011 alloy were also obtained even after 8 cycles of ARB. The AA5754 alloy suffered from severe edge and notch cracking since the first cycle. The work hardening of AA8006 alloy saturated after the 3(rd) cycle, whereas the hardness of AA5754 alloy increased steadily up to the 5(th) cycle. Monotonous increase in strength up to 280 MPa was observed in the ARB processed AA8011 alloy.