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