The Al-Sc-Y, Al-Zr-Y master alloys for modification and doping of aluminum alloys

E.A. Popova, P.V. Kotenkov, A.B. Shubin, E.A. Pastukhov

KEYWORDS:

aluminum melts, primary and secondary aluminides, cubic and tetragonal cells, structure type, transition metals, ternary master alloys, grain degradation, dispersion hardening

ABSTRACT:

The master alloys of (at.%) Al–0.45Sc–0.50Y, Al–0.45Sc–0.22Y, Al–0.22Y–0.31Zr, Al–0.12Y–0.37Zr were obtained for modifying and alloying aluminum melts. The primary aluminides of the pilot master alloys have cubic cell with the L12 structural type. This was provided by the 200-300ºC overheating the melt over liquidus temperature , by the crystallization rate of ~1000 °/sec , and by the Sc/Y, Zr/Y ratio. The presence of aluminides, with the cell crystallographically similar to the cell of aluminum matrix, is determined by formation of equlaxial grain with the size of approximately 20 mkm in the pilot master alloys. In the alloys with aluminides, obtained at slight overheat (60-100ºC) and saved the tetragonal cell, the dendrite size variation grain is formed at the same rate of melt crystallization.

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