Klymentiy N. {Sc,Ti,V}-Cu-Al systems: phase equilibria, crystal structures, mechanical and electrical properties

The isothermal sections at 800°C of the phase diagrams of the {Sc,Ti,V}-Cu-Al systems were constructed in whole concentration ranges using X-ray powder diffraction, energy dispersive X-ray spectroscopy and differential thermal analysis, and the crystal structures of the ternary compounds were refined on X-ray powder or single-crystal diffraction data. Mechanical and electrical properties of alloys of the {Sc,Ti}-Cu-Al systems were measured. In the ternary system Sc-Cu-Al, the existence of five ternary compounds was confirmed. The existence of two other ternary aluminides was revealed: Sc6Cu24.1Al11.9 and Sc3Cu7.49Al7.51, and the formation of a continuous solid solution ScCu1-xAlx were established. A new structure type, Sc6Cu24.1Al11.9 was discovered. The crystal structures of the compounds of the Sc-Cu-Al system are characterized by statistical mixtures of Cu and Al atoms. Measurements of the specific electrical resistance of the seven ternary compounds confirmed the good electrical conductivity of alloys based on copper and aluminum. In the Ti-Cu-Al system, the existence of three ternary compounds was confirmed and the boundaries of the homogeneity regions were defined. The existence of the ternary compound Ti1.15Cu0.09Al2.76 at 800°C was established. For all of the ternary compounds, measurements of the microhardness were performed. In the V-Cu-Al system, the existence of substitutional solid solutions on the basis of four binary compounds was confirmed, and the limits of their extent into the ternary system were determined along the corresponding Al isoconcentrates. On the basis of the experimental data, the peculiarities of the interaction of the components in the {Sc,Ti,V}-Cu-Al systems were analyzed and conclusions were drawn concerning the formation of ternary compounds in the systems on moving from Sc to Ti and V. The mechanical and electrical properties of the investigated compounds were compared.