Scandium effect on increasing mechanical properties of aluminum alloys

A review of the works devoted to the influence of scandium additions on the structure and physical and chemical properties of aluminum alloys is given. Small additions of Sc (0.2-0.3%wt.) make it possible to create disperse particles of intermetallic Al3Sc, which are coherently bound with the aluminum matrix. The presence of these particles, the diffusion velocity diminution, and other physical and chemical properties of Sc lead to complex change of the properties of aluminum alloys. Thus, the grain size in a cast metal decreases, the technological plasticity of alloys grows, strength and plasticity characteristics increase. The recrystallization temperature grows sharply. Due to low grain size and high recrystallization temperature these alloys become natural superplastic materials, the weldability of alloys increases, and the corrosion resistance of alloys grows. The classification of alloying elements with respect to "scandium effect" is given. Peculiarities of the influence of scandium on thermally hardenable and thermally nonhardenable wrought alloys and the cast alloys are discussed.