Novel ultra-high straining process for bulk materials—development of the accumulative roll-bonding (ARB) process

A novel intense plastic straining process named accumulative roll-bonding (ARB) is proposed. First, a strip is neatly placed on top of another strip. The two layers of material are joined together by rolling like a roll-bonding process. Then, the length of rolled material is sectioned into two halves. The sectioned strips are again stacked and roll-bonded. The whole process is repeated again and again. The process can introduce ultra-high plastic strain without any geometrical change if the reduction in thickness is maintained to 50% every rolling pass. The process has been applied to commercial aluminum (1100), Al–Mg alloy (5083) and interstitial free (IF) steel. Well-bonded bulk materials were successfully obtained. After several cycles of ARB, ultra-fine (sub-micron) grain structure with large misorientations, i.e. polycrystal, was formed and the materials were strengthened dramatically.