Scandium in aluminium alloys

A considerable part of the available literature on scandium in aluminium alloys is reviewed. Experimental data and assessments of the binary Al–Sc phase diagram, a wide range of ternary Al–Sc–X phase diagrams and a few higher order phase diagrams are accounted for, with emphasis on the aluminium rich part of the diagrams. The phase which is in equilibrium with Al, Al3Sc, can form by several different mechanisms, all of which are described. The precipitation kinetics of Al3Sc in binary Al–Sc alloys are discussed, and an overview of the reported influences of ternary alloying elements on the precipitation of Al3Sc is given. The Al3Sc phase particles can serve as a grain refiner in the Al melt, a dispersoid for…