Desktop browsers: Chrome, Firefox, Opera, Safari
Mobile devices: All iOS devices, Android (Chrome)

Internet Explorer, Android browser

Click the image to view a movie

Initiation of coupled growth in Al-Al2Cu Eutectic Alloy

Directional solidification begins from an unmelted as-cast eutectic seed as a single-phase Al2Cu layer. The Al-phase, being present at grain boundaries of Al2Cu, spreads out and covers the Al2Cu-liquid interface in a quasi-2D seaweed pattern (0:02-0:03 in the video). This "invasion" process has been observed before in transparent alloy systems (Akamatsu et al., Metall and Mat Trans A 32, (2001): 2039-48) The seaweed pattern is followed in the early stages of coupled growth by a "maze" or labyrinth pattern, which is a precursor to lamellar growth. The movie was obtained by X-ray tomography on a Phoenix Nanotom system and shows a region of about 450 μm width.

Eutectic solidification

Directional solidification of regular and irregular eutectics. Courtesy John Hunt. (98.5 Mb)

Solitary wave

A solitary wave travels from left to right along a steady lamellar eutectic front (x10 accelerated). This nonlinear phenomenon is typical of an out-of-equilibrium pattern forming system. Thin-sample directional solidification of a near-eutectic transparent alloy (CBr4-C2Cl6).
Horizontal dimension: 620 microns.(0.3 Mb) (Movie provided by Silvere Akamtsu)


Thin-sample directional solidification is used here for observing the initial stages of eutectic growth. The movie shows a mechanism by which a large eutectic grain can form. In a slightly hypereutectic alloy (transparent CBr4-C2Cl6 alloy), a thin crystal of the minority phase (faint-contrast solid-liquid interface) grows and "invades" the solidification front laterally (from left to right) on top of a single crystal of the majority phase (strong-contrast interface). Its lateral propagation velocity increases while solidification proceeds. At a certain time, the tip destabilizes and oscillates, which gives rise to a periodic eutectic structure.
Horizontal dimension: 430 microns. (Movie provided by Silvere Akamtsu) (1.2 Mb)

AlSiCu eutectic solidification

Directional solidification parallel to gravity in AlSiCu eutectic alloys. The first movie shows an unmodified irregular eutectic. Imposed temperature gradient of 23.0 K/mm, and sample velocity of 17 microns/s

The second movie shows a Sr-modified irregular eutectic. Imposed temperature gradient of 18.4 K/mm, and sample velocity of 10.5 microns/s

Eutectic solidification

Top view of a three-dimensional phase-field simulation of eutectic solidification. The growth direction is towards the observer. The composition of the liquid far ahead of the growth front is slowly varied in the course of time, such that the volume fractions of alpha (red) and beta (green) phase change with time. The initial condition is an unstable lamellar array, which rapidly splits to form beta rods. As the volume fraction of beta phase increases, the rods become thicker until a transition to lamellae occurs. In the further evolution, the alpha lamellae become thinner and thinner until they break up into alpha rods. For details, see A. Parisi and M. Plapp, Defects and multistability in eutectic solidification patterns, EPL 90, 26010 (2010). (5 Mb) This movie derives from phase-field simulations performed by Mathis Plapp and his collaborators.

Eutectic colonies

This movie shows a phase-field simulation of eutectic colony growth during directional solidification. The growth direction is upward, and the 'camera' follows the isotherms such that a flat front appears immobile in the movie. A binary eutectic (color scale red-blue) front is destabilized by ternary impurities (green) on a scale that is much larger than the lamellar spacing. For details, see M. Plapp and A. Karma, Eutectic colony formation: A phase field study, Phys. Rev. E 66, 061608 (2002). (4.3 Mb) This movie derives from phase-field simulations performed by Mathis Plapp and his collaborators.

solidification 2017 - webdesign by Comstrukt