Scandium mechanical properties

Metal-metal eutectics have been studied for many years due to their excellent mechanical properties. Recently, oxide-oxide eutectics were identified as materials with potential use in photonic crystals. For example, rodlike micrometer-scaled microstructures of terbium-scandium-aluminum garnet terbium-scandium per-ovskite eutectics have been solidified by the micro-pulling-down method (Pawlak et al., 2006). If the phases are etched away, a pseudohexagonally packed dielectric periodic array of pillars or periodic array of pseudohexagonally packed holes in the dielectric material is left. 

Senkov, O.N., Miracle, D.B., Milman, Y.V., Scott, J.M., Lotsko, D.V. and Sirko, A.I. (2002) Low temperature mechanical properties of scandium-modified Al-Zn-Mg-Cu alloys, Mater.Science Forum 396-402, 1127-1132. 

Scandium, yttrium, and the lanthanide mettils comprise 17 elements for which systematically-determined mechanical property data are sparse. Pioneering work on the mechanical properties of rare earth metals was done in the mid to late 1950 s and was conducted almost exclusively by three groups B. Love and associates at Research Chemicals, Inc. C.R. Simmons and associates at General Electric Co. and E.M. Savitskiy and associates in the USSR. Since that time the number of investigations has increased and the property values have changed considerably with improvements in metal purification methods. 

Simmons, C.R., 1%1, The Mechanical Properties of Yttrium, Scandium, and the Rare Earth Metals, in Spedding, F.H., and A.H. Daane eds.. The Rare Earths (John Wiley and Sons, New York), pp. 428-452. a) Lithium-reduced scandium fluoride, distilled and arc-melted into buttons, b) Calcium reduced scandium fluoride in tantalum crucibles contain 2-5 w/o Ta. c) Arc-melted yttrium low value for 500 ppm O and 700ppm F, high value for 2500 ppm O, 3000 ppm F. (500 kg. load, 10 mm indenter.)... 

Simmons, C.R., 1961, The Mechanical Properties of Yttrium, Scandium, and the Rare Earth Metals, in Spedding, F.H., and A.H. Daane eds.. The Rare Earths (John Wiley and Sons, New York), pp. 428-452. 

Fig. 8.11. Temperature dependence of the tensile and compressive mechanical properties of scandium. Geiselman (1%2) as-cast about 8000 ppm impurities including 4600 ppm oxygen. Sokolov (1969a) and Sokolov (1970a) wrought claimed 99.99% Sc but no analysis was given.

Sokolov et al. (1969a) at about 175 K indicate their material was relatively brittle at this temperature. A rather rapid rise of ductility in tension (Sokolov et al., 1969a) and compression (Sokolov et al., 1970a) near 700 to 800 K is probably associated with recrystallization during testing since this should be the appropriate temperature range for dynamic recrystallization. It seems rather evident that none of the data shown in fig. 8.11 reveals the intrinsic mechanical properties of pure scandium. 

Electrical properties of thin rare earth oxide film have also been studied. The conductivity of praseodymium thin film oxide was measured as a function of temperature and oxygen pressure [9]. The oxide film was found to act as a p-type conduction at temperatures high than 630°C and was a n-type semiconductor at the temperatures of 400-630°C. Thermally evaporated EU2O3 thin film on a glass substrate is also obtained in an amorphous state. From the measurement of frequency dependence of the ac conductance, the predominant mechanism could be ascribed to the result of a hopping type. The ac conductivity measurements were also carried out for thin film of SC2O3 at temperatures between 4 and 295 K [10]. The conductivity was found to obey the relationship of ai(ffl)=Aco which depends on frequency and s is dependent on temperature and is a little lower than unity. By using a classical hop mechanism between randomly distributed localized states, a model was proposed and applied to scandium oxide with the assumption that the localized states are caused by lattice vacancies. The model is expected to be... 

The properties of aluminum alloys (mechanical, physical, and chemical) depend on alloy composition and microstructure as determined by casting conditions and thermomechanical processing. While certain metals alloy with Al rather readily [9], comparatively few have sufficient solubility to serve as major alloying elements. Of the commonly used alloying elements, magnesium, zinc, copper, and silicon have significant solubility, while a number of additional elements (with less that 1% total solubility) are also used to confer important improvements to alloy properties. Such elements include manganese, chromium, zirconium, titanium, and scandium [2,10]. 

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