Influence of grain-refiner addition on the morphology of fe-bearing intermetallics in a semi-solid processed Al-Mg-Si alloy

© The Minerals, Metals & Materials Society and ASM International 2013The three-dimensional morphologies of the Fe-bearing intermetallics in a semisolid-processed Al-Mg-Si alloy were examined after extracting the intermetallics. α -AlFeSi and β-AlFeSi are the major Fe-bearing intermetallics. Addition of Al-Ti-B grain refiner typically promotes β-AlFeSi formation. β-AlFeSi was observed with a flat, plate-like morphology with angular edges in the alloy with and without grain refiner, whereas α -AlFeSi was observed as "flower"-like morphology in the alloy with grain refiner. © 2013 The Minerals, Metals & Materials Society and ASM International

Evolution of intermetallics, dispersoids and elevated-temperature properties at various Fe contents in Al-Mn-Mg 3004 alloys

Nowadays, great interests are rising on aluminum alloys for the applications at elevated temperature, driven by the automotive and aerospace industries requiring high strength, light weight and low cost engineering materials. As one of the most promising candidates, Al-Mn-Mg 3004 alloys have been found to possess considerably high mechanical properties and creep resistance at elevated temperature resulted from the precipitation of a large number of thermally stable dispersoids during heat treatment. In present work, the effect of Fe contents on the evolution of microstructure as well as high temperature properties of 3004 alloys has been investigated. Results show that the dominant intermetallic changes from α-Al(MnFe)Si at 0.1 wt. % Fe to Al6(MnFe) at both 0.3 and 0.6 wt. % Fe. In the Fe range of 0.1 to 0.6 wt. % studied, a significant improvement on mechanical properties at elevated temperature has been observed due to the precipitation of dispersoids, and the best combination of yield strength and creep resistance at 573K (300°C) is obtained in the 0.3% Fe alloy with finest size and highest volume fraction of dispersoids. The superior properties obtained at 573K (300°C) makes 3004 alloys more promising for high temperature applications. The relationship between the Fe content and the dispersoid precipitation as well as the materials properties has been discussed

Estimation of dislocation densities in cold rolled Al-Mg-Cu-Mn alloys by combination of yield strength data, EBSD and strength models

Al-Mg-Cu-Mn alloys have been developed for the packaging industry, in which large cold-working deformations are normally applied that can produce high dislocation densities. In this study, we present a simplified model for the yield strength contributions and apply that to obtain the dislocation densities by determining the orientation factors, which can be obtained via the crystal information of electron backscatter diffraction (EBSD). One alloy subjected to three cold-rolling reductions (10%, 40% and 90%) has been analysed by EBSD, and the density of dislocations are estimated using the strengthening model. This assessment suggests that dislocation densities by the Taylor model are roughly consistent but slightly lower than those determined by transmission electron microscopy