DIRECTIONAL GROWTH OF ZN-AL-SI-CU ALLOYS

ALICIA ESTHER ARES; CARLOS ENRIQUE SCHVEZOV

Paraty - Rio de Janeiro, Brasil

Otro; VII ENCONTRO DA SOCIEDADE BRASILEIRA DE CRESCIMENTO DE CRISTAIS; 2007

SBCC

The present investigation was undertaken to investigate experimentally the directional solidification of Zn-Al-Si-Cu alloys under different conditions of heat transfer efficiencies at the metal/mould interface. The CET is observed; grain sizes and dendritic spacings are measurement and relate the observations to the solidification thermal parameters: cooling rates, growth rates, thermal gradients and recalescence determined from the temperature versus time curves. In addition, there is an increase in the velocity of the liquidus front faster than the solidus front, which increases the size of the mushy zone. The size of the equiaxed grains increases with distance from the transition, observation which was independent of alloy composition. The observations indicate that the transition is the result of a competition between coarse columnar dendrites and finer equiaxed dendrites.