A metallurgical investigation into the friction welding of rapidly solidified, dispersion-strengthened aluminum alloys

The objective of this study was to investigate the similar- and dissimilar-alloy friction welding of dispersion-strengthened, elevated-temperature aluminum alloys. Results showed that both inertia- and linear-friction welding can be effectively utilized for the joining of state-of-the-art Al-Fe-X type alloys. Inertia-friction welding using a sufficiently high axial force minimized microstructural coarsening and, thereby, optimized mechanical properties of both similar- and dissimilar-alloy welds.;For the similar-alloy welds in Al-Fe-Si-V alloys, mechanical properties were dependent principally on the extent of dispersoid coarsening and redistribution (via non-homogenous deformation) across the weld interface region. Analytical-electron microscopy analysis determined that the fine, spherical Al;Dissimilar-alloy inertia-friction welds between Al-9Fe-3Mo-1V and 2024-T351 exhibited macroscopic interface curvature with penetration of the 2024-T351 into the Al-9Fe-3Mo-1V. In contrast, dissimilar-alloy inertia-friction welds produced between Al-Fe-V-Si alloys and 2024-T351 exhibited relatively flat macroscopic interfaces. Although dispersoid coarsening in the Al-Fe-X alloys was minimal at the weld interface, appreciable metallurgical change occurred in the precipitation-strengthened 2024-T351 alloy. Despite these metallurgical changes, and occasional fracture along the weld interface, relatively high joint efficiencies comparable to those of similar alloy welds were measured.;Dissimilar-alloy inertia-friction welds produced between the dispersion-strengthened Al-Fe-Si-V alloys and titanium alloys exhibited marginal integrity and strength due to the large strength differences between the alloys and enrichment of dispersoids at the interface due to the nonuniform deformation, both of which precluded effective bonding.;Elevated-temperature exposure experiments on similar-alloy inertia-friction welds in Al-Fe-V-Si at 425...