US-Egypt Cooperative Research: Friction Stir Welding of Superplastic Alloys

University Of South Carolina At Columbia, Columbia SC

Investigators

Abstract

0108894 Lyons Description: This award is to support a collaborative project between Dr. Jed Lyons and Dr. Anthony Reynolds, both in the Department of Mechanical Engineering at the University of South Carolina, Columbia, South Carolina, and Dr. Hanadi Salem, Department of Mechanical Engineering, the American University in Cairo, Cairo, Egypt. They plan to develop manufacturing technologies for structural metals for the transportation industry. Specifically, research will be conducted to develop a fundamental understanding of the effects of friction stir welding (FSW) on the superplastic forming (SPF) behavior and ambient temperature properties of Al-Cu-Li sheets. FSW is a new solid-state welding process. Its advantages relative to traditional fusion welding techniques are primarily attributable to the fact that no melting is required. SPF alloys are good candidates for FSW due to the need to maintain a dynamically recrystallized fine grain microstructure. Preliminary collaborative work by the PIs indicates that SPF behavior can be retained in superplastic Weldalite 049 and 2095 aluminum alloys after FSW. An understanding of the role of FSW process variables on the constituent properties and microstructure through the weld nugget and adjacent thermo-mechanically affected zones (TMAZ) is required in order to make the process commercially viable. Research techniques and instruments to be employed include an instrumented friction stir welding machine, thermo-mechanical testing facilities for measuring tensile properties and SPF behavior, computer vision technology including digital image correlation and microstructural characterization with scanning electron microscope (SEM), transmission electron microscope (TEM) and optical microscopy and x-ray spectroscopy analysis. Scope: The project supports collaboration between two teams of investigators to carry out an important research project. The US team will be responsible for determining and investigating the FSW process conditions and for making the welds. They will test the FSW process at various conditions of weld and with various weldalite alloys with variable copper and lithium contents and different thickness. Dr. Salem will, with the assistance of a US graduate student, run the SPF tests and perform TEM investigations. Dr. Salem will also direct one of her graduate students at AUC in completing the optical and SEM examinations for the same alloys. Using the resources at both the University of South Carolina and the American University in Cairo, this project contributes to the development of combined FSW/SPF processes that enable the net-shape fabrication of complex multi-sheet structural components from custom blanks. The project will include two US scientists and one US graduate student who will gain experience in international cooperative research. The proposal meets the INT objective of supporting collaborative research in areas of mutual interest. This project is being supported under the US-Egypt Joint Fund Program, which provides grants to scientists and engineers in both countries to carry out these cooperative activities.