Friction stir processing for superplasticity and other applications

Abstract

Friction stir welding is a recent welding technology that had expanding the capabilities of welding aluminum alloys. From this process, it was discovered that the microstructural properties of a metal could be altered with a single pass of the tool, and from this the area of friction stir processing can be expanded beyond welding. While friction stir processing is a new field of research, many areas of study have been discovered including the area of friction stir superplasticity. Using the small grain size achieved by the process and the high grain boundary mis-orientation angle, it has been found that friction stir processing is capable of creating high strain rate superplasticity in aluminum alloys. This study evaluates the technology of friction stir processing. In detail, the study examines the applications, competing technologies, intellectual property, and the start of the business aspects of the technology. In summary, it was found that the main applications for the technology are in the automotive and aerospace industries. The largest competing technology generally uses a six-step process that does not allow for high strain rates and thick sections. Both of these can be achieved by friction stir processing. Key patents in the area were also examined. In the business evaluation it was determined that the technology would likely be applied first in the automotive industry and used by a major automotive manufacturer in order to reduce costs. Overall, friction stir superplasticity appears to have a lot of potential for future superplasticity applications.