Superplastic Blow Forming of 2219 Aluminium Alloy

摘要

Superplasticity in 2219 aluminum alloy was achieved through thermomechanical processing. Tension tests showed that the alloy e xhibits superplastic behavior in the temperature range of 450-540℃ and strain rates ranging from 2.2 x 10~(-5) to 1.1 x 10~(-1) s~(-1). A maximum elongation-to-failure of 670% was recorded at 500℃ and at the initial strain rate of 2.2 x 10~(-4) s~(-1). High cavitation level and intensive grain growth were observed. Sheet of the 2219 aluminum alloy was blow formed into conical shape using two different methods: simple negative and backpressure forming. A strain of 2.1 was obtained at 500℃ under the backpressure blow forming condition. It was found that elongation to failure under blow forming with backpressure is about 1.5 times higher than that under a simple female forming. Microstructural evolution of blow formed parts was also examined.