Yoshihiro Saito, Hiroshi Utsunomiya, Nobuhiro Tsuji,Tetsuo Sakai and Ren-Guo Hong
Division of Materials Science and Engineering, Graduate School of Engineering, Osaka University, Suita 565-0871
It is known that an ultra-fine grain size can be achieved by a special intense plastic straining processes. In this paper, the authors propose a novel intense plastic straining process named the Accumulative Roll-Bonding(ARB) for bulk materials. In the process, a strip is put on another strip neatly, at first. The two layered materials are joined together by rolling in the manner of a conventional 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 can be repeated again and again. The achieved strain by the process is unlimited since repetition times are endless in principle. The proposed ARB process has been applied to a commercial aluminum (1100). The whole process is repeated up to 8 cycles at 473 K and well bonded strips are successfully obtained. After several cycles, ultra-fine (sub-micron) grain microstructure separated by high-angle grain boundaries is formed. The ARB process increases the ultimate tensile strength from 80 MPa to 300 MPa. It is concluded that the proposed ARB process is suitable for intense plastic forming and strengthning of bulk materials.
(Received December 22, 1998; In Final Form March 17, 1999)
sub-micron grain, ultra-high straining, accumulative roll bonding, super metal, mechanical property, texture, aluminum
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