Initial Crystallisation or Nucleation in a Liquid Aluminium

Writing By Reza Haghayeghi

Step-by-step in situ near-atomic-resolution observations were presented for initial crystallization or nucleation in a liquid Al-10Mg (wt%) alloy containing spinel (MgAl2O4) seeds.

Ordering of Al atoms was observed in the alloy at the interface with spinel at the superheat of 73 _C or at the melt temperature of 680 _C, where three ordered layers of Al atoms formed and disappeared alternately.

When cooled to the approximate liquidus of the alloy, 607 _C, three similar but more stable ordered layers of Al atoms formed.

Subsequent crystallization occurred first through the formation of partially close-packed Al atoms on the solid-like outer ordered layer of Al atoms, followed by further crystallization into more close-packed Al atoms.

Writing By Reza Haghayeghi

 2017 Elsevier B.V. All rights reserved.

Keywords:

Solidification

Solid-liquid interface

Epitaxial growth

Heterogeneous nucleation

Writing By Reza Haghayeghi

Step-by-step in situ near-atomic-resolution observations were presented for initial crystallization or nucleation in a liquid Al-10Mg (wt%) alloy containing spinel (MgAl2O4) seeds.

Ordering of Al atoms was observed in the alloy at the interface with spinel at the superheat of 73 _C or at the melt temperature of 680 _C, where three ordered layers of Al atoms formed and disappeared alternately.

When cooled to the approximate liquidus of the alloy, 607 _C, three similar but more stable ordered layers of Al atoms formed.

Subsequent crystallization occurred first through the formation of partially close-packed Al atoms on the solid-like outer ordered layer of Al atoms, followed by further crystallization into more close-packed Al atoms.

Writing By Reza Haghayeghi

 2017 Elsevier B.V. All rights reserved.

Keywords:

Solidification

Solid-liquid interface

Epitaxial growth

Heterogeneous nucleation

Writing By Reza Haghayeghi

Step-by-step in situ near-atomic-resolution observations were presented for initial crystallization or nucleation in a liquid Al-10Mg (wt%) alloy containing spinel (MgAl2O4) seeds.

Ordering of Al atoms was observed in the alloy at the interface with spinel at the superheat of 73 _C or at the melt temperature of 680 _C, where three ordered layers of Al atoms formed and disappeared alternately.

When cooled to the approximate liquidus of the alloy, 607 _C, three similar but more stable ordered layers of Al atoms formed.

Subsequent crystallization occurred first through the formation of partially close-packed Al atoms on the solid-like outer ordered layer of Al atoms, followed by further crystallization into more close-packed Al atoms.

Writing By Reza Haghayeghi

 2017 Elsevier B.V. All rights reserved.

Keywords:

Solidification

Solid-liquid interface

Epitaxial growth

Heterogeneous nucleation