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°C and strain rates ranging from 2.2×10{sup}(-5) to l.l×10{sup}(-1) s{sup}(-1). A maximum elongation-to-failure of 670% was recorded at 500°C and at the initial strain rate of 2.2×10{sup}(-4) s{sup}(-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°C 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.