Accumulative Roll Bonding Technology Of Aluminum Alloys

AUTHOR/S: S.Argentero

ABSTRACT

The Accumulative Roll Bonding (ARB) is an experimental severe plastic deformation (SPD) rolling procedure aimed at refining the grain structure of suitable alloys so as to increase their tensile yield strength. The process consists in rolling a couple of overlapped sheets at a given temperature and thickness reduction ratio (e.g. 50%). At suitable ARB conditions a bonding interface forms between sheets during the deformation process, due to temperature and plastic strain. The product of the first rolling cycle is cut in two similar sheets which are again overlapped and rolled again by the same procedure as the first rolling cycle. Several ARB rolling cycles can be repeated on the same work-piece. A strain hardening aluminum alloy (AA5083) has been rolled up to ten times, after optimum process window identification, so as to produce a resulting sheet comprehensive of 1024 layers. The final sample has been machined for room temperature tensile, compression, bending tests and for MO and TEM (Transmission Electron Microscope) observation. The results shown an increase of RT yield tensile and compressive stress and ultimate tensile stress and a decrease in RT maximum strain. TEM observation has shown the formation of very well defined and thin cell boundaries and, at higher scale, the formation of deformation bands parallel to the rolling direction of the sheet.

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