Tsutomu Tagata

Superplastic Properties of a Newly Developed Al-Mg-High Mn Aluminum Alloy Sheet

A new superplastic Al-Mg-high Mn alloy called a high-Mn alloy in the present paper was developed. The superplastic properties of the high-Mn alloy were evaluated in comparison with a conventional superplastic 5083 alloy which was manufactured under the same industrial mass production process. The high-Mn alloy sheet of a middle thickness shows a lager elongation to failure at temperatures below 783K, and show better superplastic formability and less cavitation volume than the 5083 alloy. These superior characters of the high-Mn alloy may be ascribable to finer grain structure formed in the alloy.

Development of aluminum alloy sandwich panel using roll bonding and superplastic buldge forming.

The possibility of fabricating the metallic bonded truss structured aluminum board was studied by the combination of the roll bonding process and superplastic forming. Al–1.6%Mn alloy sheet was first pre-clad to the superplastic 5083 aluminum alloy sheet. These sheets were piled in three layers and then hot roll bonded. Here, the anti-bond coat was printed on both sides of the core sheet in striped pattern before hot roll bonding. These hot rolled bonded sheets were next subjected to cold rolling to obtain the superior superplasticity. The three layered roll bonded sheets were set between flat dies at superplastic temperature and the truss structured board was formed superplastically by applying the internal gas pressure to the un-bonded area with gradual opening of the flat dies. It was found that a higher pressure and a slower gap opening speed was desirable to obtain a flat surface board. As the results, the truss structured high rigidity board with flat surfaces was obtained.