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Título:
COMPOSITION, STRUCTURES AND PROPERTIES OF ZINC-ALUMINUM ALLOYS AND COMPOSITES WITH COLUMNAR TO EQUIAXED TRANSITION
Autor/es:
ALICIA ESTHER ARES; SERGIO FABIAN GUEIJMAN; CARLOS ENRIQUE SCHVEZOV
Lugar:
Salt Lake City, Utah, Estados Unidos
Reunión:
Conferencia; The 15th INTERNATIONAL CONFERENCE ON CRYSTAL GROWTH; 2007
Institución organizadora:
ICCG15
Resumen:
In general, equiaxial structures has bigger resistance to the total tension, bigger durability to fatigue efforts, second phases more finely dispersed, improvements to compensate the impact, smaller warm fissure, improvements of the workability; and columnar structures are used in single crystals production for turbine blades, they has bigger resistance to the traction and the compression, bigger resistance to the flexion, bigger resistance to the torsion. To understand the interaction between the parameters involved in the columnar to equiaxed transition (CET) has gained considerable attention over the last two decades in the study of the structure of ingot castings. The present study was undertaken to investigate the columnar to equiaxed transition in Zn-Al alloys (Zn-1%Al, Zn-2%Al, Zn-3%Al, Zn-4%Al, Zn-16%Al, Zn-27%Al, Zn-50%Al) under different conditions of superheat and heat transfer efficiencies at the metal/mould interface. The CET is observed; grain sizes are measured and the observations related to the solidification thermal parameters: cooling rates, growth rates, thermal gradients and recalescence determined from the temperature versus time curves. Also, zinc - aluminum alloys with different compositions and, with reinforcing particles of silicon carbide and alumina, were solidified and the structure was analyzed. The analyses were done performing hardness test (HV) and quantitative metallography. Composition analysis of the different alloying elements along the cast samples were done by SEM (Scanning Electron Microscopy) and EDXA (Energy Dispersive X-Ray Microanalysis). Several correlations between properties, structures and compositions were found.