Koji Ichitani

High Temperature Deformation Behavior of a 6N01 Aluminum Alloy Extrusion with a Seam Weld

An aluminum alloy hollow extrusion made with a porthole-die has a few seam welds. It is known that the deformation behavior of a weld region is different from that of a non-weld region at room temperature. In the present study, the influence of a seam weld on the high temperature deformation of a 6N01 aluminum alloy extrusion bar was investigated. The elongation of the alloy with the seam weld was significantly lower than that of the alloy without it. This was because the alloy with the seam weld started localized deformation at a very early stage of deformation. An orientation analysis with an electron backscatter diffraction suggested that a difference in recrystallization texture between weld and non-weld regions would accelerate the start of localized deformation.

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.