Papers by Keyword: Al-Sc

Abstract: The effect of prior and subsequent precipitation on recrystallization behavior during the isothermal annealing of an Al-0.2%wt.Sc alloy heavily deformed by accumulative roll bonding (ARB) up to 10 cycles at ambient temperature was investigated. Three kind of different microstructures, i.e., solution treated one, 300°C pre-aged one and 400°C pre-aged one, were prepared as the starting structures for the ARB process. It is found that precipitation pinning effect of Al3Sc suppresses recrystallization and especially the 400°C pre-aging was effective to stabilize the ultrafine grained structure of the matrix. Dissolution of pre-aging Al3Sc precipitates was suggested by re-precipitation during annealing of the ARB processed specimens at around 300°C.

Abstract: The addition of scandium severely retards the recrystallization of Al-Sc alloys when it is present in the form of fine Al3Sc precipitates. Though many studies have focused on the role of Al3Sc in the deformation and recrystallization of pre-aged or hot deformed Al-Sc alloys, recent studies on the annealing response of solutionized and cold rolled material have shown various possibilities for microstructural stability depending on the relative kinetics of precipitation and recrystallization. In this study, the microstructural evolution of solutionized and cold rolled Al- 2.9wt%Mg-0.16wt%Sc has been followed in order to evaluate the role of imposed strain and annealing temperature on the recrystallization kinetics.

Abstract: The review of the works devoted to the influence of scandium on the structure, mechanical behavior and corrosion resistance of aluminum alloys is given. The wrought thermally non-hardenable alloys of Al- Mg system and thermally hardenable high-strength alloys of Al-Zn- Mg-Cu system are considered. The influence of Sc on the glass forming ability of amorphous alloys and on the superplastic behavior of aluminum alloys is discussed.

Abstract: Scandium additions are known to offer a number of benefits to aluminium alloy performance. Many of these benefits can be attributed to the precipitation of fine Al3Sc particles. These particles are fully coherent with the aluminium matrix when they are small, but can lose coherency as they grow or coarsen. In this work, the change in coherency has been studied in an Al- 0.12 wt%Sc alloy over the temperature range 300-425oC. Three coherency regimes were identified, consistent with previous observations. The time and temperature range over which coherency changes occur have been measured for a range of conditions and correlated with the precipitation kinetics and the predictions of a model for Al3Sc precipitation. The effect of the coherency change on the particle morphology has also been investigated.