Hybrid superplastic forming
Superplastic forming (SPF) has been a widely used technology in the aerospace and automotive industries for the manufacturing of light weight components. This report would address the formability of a non superplastic aluminum alloy AA5083.The study of its formability would be done by conducting a s...
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| Format: | Final Year Project (FYP) |
| Language: | English |
| Published: |
2010
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| Online Access: | http://hdl.handle.net/10356/39427 |
| Summary: | Superplastic forming (SPF) has been a widely used technology in the aerospace and automotive industries for the manufacturing of light weight components. This report would address the formability of a non superplastic aluminum alloy AA5083.The study of its formability would be done by conducting a series of high temperature tensile tests. Furthermore non superplastic AA5083 blanks of 3 mm thickness are being used to conduct hybrid superplastic forming tests. The finite element method (FEM) was also used to further study the hybrid superplastic forming method.
The tensile tests and microstructure study indicated that the material exhibited weak strain hardening effects at relatively low strain rates. This presented itself by the low yield stress values. There were also signs of cavitation and grain growth at higher temperatures and low strain rate values and this showed up as black voids in the micrographs.
The hybrid superplastic forming method is a combination of mechanical preforming with superplastic forming. This method has taken advantage of both the benefits of deep drawing and superplastic forming. It is through this method that the low forming rates of conventional superplastic forming was overcome. This method used a total of 9 minutes to form a specimen at temperatures of 400 ºC to 500 ºC. The thickness profile of the formed specimen was conducted to quantify its formability and microstructural study was being done at the bends of the formed specimen to better understand the microstructural changes during the entire forming process.
The FEM simulation was divided into a 2 step process. The Von Mises stress and thickness distribution pseudo colour simulations were used as a form of analysis. During the deep drawing process, the areas of high stress are located at where the punch comes in contact with the blank. During the superplastic forming process the stress levels throughout the specimen were lower than those experienced during the mechanical preforming phase. Further studies on the effects of friction and blank holder force were also conducted. By using the draw-in length, bulge height and thickness distribution the results from the various simulations and their formability could be quantified. From the results it was noted that friction was a more important criteria to consider as compared to blank holder force when optimizing the hybrid SPF process. |
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