Formability and cavitation behavior of superplastic AA5083 aluminum alloy under biaxial tension
(1.上海市上海交通大学机械工程学院
2.School of Mechanical Engineering, Shanghai Jiaotong University, Shanghai 200030, China)
2.School of Mechanical Engineering, Shanghai Jiaotong University, Shanghai 200030, China)
Abstract: The superplastic forming potential of two fine-grained 5083 aluminum alloys were studied under biaxial tension using a pneumatic bulge test. Experiments were performed at temperatures ranging from 475 to 525 ℃ with three different strain paths ranging from equi-biaxial to approaching plane strain. The shape of the forming limited diagram(FLD) is found to be significantly different from FLDs commonly used in room temperature stamping. The effects of temperature on final thickness distribution, dome height and cavitation were investigated for the case of equi-biaxial stretching. Increasing temperature in free bulge forming can improve the thickness distribution of final parts but have no significant effect on dome height. The results indicate that determination of forming limits in SPF cannot be represented with a simple FLD and additional metrics such as external thinning and internal cavitation needed to determine the SPF potential of a material.
Key words: AA5083 aluminum alloy; superplastic forming; forming limit; cavitation