INVESTIGADORES
FABIETTI Luis Maria Rodolfo
artículos
Título:
The development of solidification microstructures in presence of lateral constraints
Autor/es:
L. M. FABIETTI; V. SEETHARAMAN ; R. K. TRIVEDI
Revista:
METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE
Editorial:
SPRINGER
Referencias:
Lugar: Berlin; Año: 1990 vol. 21 p. 1299 - 1310
ISSN:
1073-5623
Resumen:
The effect of a sudden change in cross section on the
microstructural development has been investigated by the directional
solidification technique. Experiments have been carried out in a transparent
model system of succinonitrile-acetone so that the dynamical changes in the
interface shapes can be monitoredin
situ as the interface travels from a region of uniform cross
section to a region of sharply reduced cross section. Different experimental
conditions which give rise to initial steady-state planar, cellular, and
dendritic interfaces have been investigated. Significant changes in
microstructures have been observed as the interface approaches a sharply
reduced cross section. The planar interface undergoes transitions to cellular
and dendritic morphologies as the cross section is reduced, and reverse
transitions are observed as the cross section is then increased gradually to
its original value. An initial cellular interface is found to become dendritic
as the cross section is reduced, and again it becomes cellular as the cross
section is increased. When the experimental conditions are designed to give
initial dendritic structures, the change in microstructure is found to occur
only when the reduced cross section is of the order of primary dendrite
spacing. When the reduced cross section is more than about 5 times the primary
spacing, no appreciable change is observed in the dendritic array which travels
across the cross-sectional change. The dynamical changes in the interface shape
and the microstructural transitions that occur with the change in cross section
have been examined quantitatively and discussed.