Effects of Sc(Zr) on the microstructure and mechanical properties of as-cast Al–Mg alloys

Abstract

Both the addition of 0.6% Sc and simultaneous addition of 0.2% Sc and 0.1% Zr exerted a remarkable effect on grain refinement of as-cast Al–Mg alloys, changing typical dendritic microstructure into fine equiaxed grains. Such effect was found to be related to the formation of primary particles, which acted as heterogeneous nucleation sites for α-Al matrix during solidification. Primary particles formed in Al–Mg–Sc–Zr alloy could be identified as the eutectic structure consisting of multilayer of ‘Al3(Sc,Zr) + α-Al + Al3(Sc,Zr)’, with a ‘cellular-dendritic’ mode of growth. In addition, an attractive comprehensive property of as-cast Al–5Mg alloy due to the addition of 0.2% Sc and 0.1% Zr was obtained.

Microstructure and mechanical properties of Al–Si–Mg–Cu–Ti alloy with trace amounts of scandium

“…Furthermore, Sc is also known to be a most effective modifier of aluminium alloys [18–20]. Grain refinement, the modification of eutectic Si and the formation of nanoscale precipitates that pin sub-grain and grain boundaries can be achieved by the addition of Sc [20–24]. Summarising what we know from the discussion above, multi-microalloying is an effective means of achieving multiple effects.…”

Ca-modified Al–Mg–Sc alloy with high strength at elevated temperatures due to a hierarchical microstructure

“…The Al 4 Ca phase forming a network (or semi-network) structure can be observed at the grain boundaries. In addition, primary Al 3 (Sc,Zr) crystals with a polyhedral shape, characteristic for binary Al-Sc alloys [35,36], were observed.…”

Effects of Sc and Zr Addition on Microstructure and Mechanical Properties of AA5182

“…As shown by Filatov [ 6 ], the addition of Sc to the Al-Mg system alloy results in grain refinement, dendrites elimination and additional strengthening. For purposes of grain refinement and strength enhancement, the added amount of Sc needs to be higher than 0.55% (eutectic composition) [ 7 ]. Teng’s study shows that the grain size of AA7055 was reduced from 30 μm to 10 μm with the addition of 0.25% Sc, demonstrating that in multicomponent Al alloys grain refinement can still be achieved with a lower addition of Sc than the eutectic composition [ 8 ].…”

“…In order to expand the application of 5182 alloy, improving its strength is of foremost importance. Microalloying 5182 alloy by Sc or Zr is one of the effective approaches for enhancing its mechanical properties [ 7 ] that has been less studied. The main strengthening mechanism in 5182 alloy is the solid solution strengthening brought by Mg and Mn [ 4 ].…”