Superplasticity and superplastic forming ability of Al-Mg-Sc alloy
(1.江苏省南京市南京航空航天大学机电工程学院
2.College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China)
2.College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China)
Abstract: The superplasticity and formability of a cold-rolled Al-6Mg-0.2Sc alloy with coarse grains were investigated. High temperature tensile tests were performed in the temperature range of 400-500 ℃ with strain rates ranging from 2.0×10-4 to 2.0×10-2 s-1, and the maximum elongation of 421% was obtained at 450 ℃ and strain rate of 2.0×10-4 s-1. Superplastic bulging tests of a square conical shaped part were carried out under an optimum superplastic condition, with the wall thickness reduction less than 8%, which illustrates that the alloy has good superplastic formability. The cavities in the sections of the tensile specimens and the bulging parts were analyzed, which can be reduced greatly by imposing proper backpressure in the bulging process.
Key words: Al-Mg-Sc alloy; aluminum alloy; superplasticity; formability; cavity; backpressure