摩擦撹拌インクリメンタルフォーミング法による<br>A5052板の成形

Abstract

5000 series aluminum alloys do not have sufficient ductility and their applications are limited. To enhance the use of these alloys, it is necessary to develop new forming processes with high formability. The authors have developed a friction stir incremental forming method of forming magnesium alloy sheets without heating and reported on the formability of magnesium alloy sheets at room temperature. In this study, friction stir incremental forming was applied to forming A5052 aluminum alloy sheets, and the formability of these sheets was investigated. Tool rotation rate, tool feed rate and the half apex angle of the pyramidal frustum were changed. Hardness test and tension test on the formed parts were also carried out. A5052 sheets with a 0.5 mm thickness were successfully formed into a pyramidal frustum with a minimum half apex angle of 20°. This result coincides with an elongation of 192% although the fracture elongation of those sheets in the tension test at room temperature was only 14%. The Vickers hardness and tensile strength of the A5052 parts formed by the developed method were decreased compared with those of the unformed ones. Even with added strain by forming, however, the elongation of formed parts was greater than that of the unformed ones owing to the occurrence of grain refinement by dynamic recrystallization during forming.