DIRECTIONAL SOLIDIFICATION OF ALUMINUM MATRIX COMPOSITES

ALICIA ESTHER ARES; ELVIO DE NÁPOLE GREGOLIN; RUBENS CARAM; CARLOS ENRQIUE SCHVEZOV

Charlotte, North Carolina -USA.

Simposio; LIGHT METALS 2004; 2004

The Minerals, Metals and Materials Society (TMS)

It has been seen recently a progressive increase in the research of new techniques and processes for obtaining metal matrix composites (MMC). The subject of this paper is to study the structure of Al-5%wtSiO fiber composite during directional solidification, due to its excellent mechanical properties and light weight. The columnar-to-equiaxed transition (CET) was observed in the samples directionally solidified from the chill zone under different solidification conditions. The transition occurs when the gradient in the liquid ahead of the columnar dendrites reaches values between -2.70 °C/cm and -1.15 °C/cm and the growth velocities reach values between 0.04 cm/s and 0.25 cm/s. The microstructure obtained is analyzed taking into account the characteristics of the alloy and the temperature profiles at the solidification interface. The following tests were carried out on the composite: EDS, Vickers micro-hardness and optical microscopy. The results of the analysis are compared with those obtained in Al-Si and Al-Si-Cu alloys.