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Structural Chemistry & Crystallography Communication
ISSN: 2470-9905
June 04-05, 2018
London, UK
Crystallography 2018
Page 14
3
rd
Edition of International Conference on
Advanced Spectroscopy,
Crystallography and Applications
in Modern Chemistry
P
roperties of materials are governed by their microstructures,
which in turn are controlled by the phase transformations
at a given composition. To obtain the desired microstructure,
it is essential to understand the phase transformations that
occur in the material. Crystallography of phase transformations
defines the morphology of microstructures, explains the actual
phase transformation process at an atomic level and describes
the relationship between the new phase and the parent phase.
Hence, the crystallography controls the final properties of
materials. In the past decades, although a number of theories/
models have been developed to understand the crystallography
of phase transformations, none of them can be used to design
new materials and processes until the edge-to-edge matching
(E2EM) model became available [1]. Development of the E2EM
model was based on the principles that the nature of a coherent
or semi-coherent interface and the associated crystallographic
relationships are governed by minimisation of interfacial energy
between two crystals; and that the necessary and sufficient
condition forminimisationof the interfacial energy is tomaximize
the atom matching. The best and most effective approach to
achieve the maximum atom matching is the matching of atom
rows that are close packed or nearly close packed and are
contained in the matching planes that are arranged to meet in
the “edge to edge” manner as shown in following figure.Major
advantage of the E2EM model over all other previous models
is its predictive capacity from the first principle. Thus, it can be
used to design new alloys and processes. In this presentation,
after briefly reviewing the success of this model in predictions
of the crystallographic features of diffusion controlled phase
transformations in solids [1], its applications in development
of new and more effective grain refiners for cast metals,
including magnesium alloys [2], zinc alloys [3] and steels [4], are
introduced. Predictions of the textures and growth features of
epitaxial growth and crystalline nanowires [5] are also presented.
Figure:
Schematic illustration of the edge-to-edge matching model
Recent Publications
1. Zhang M-X, Kelly P (2014) Crystallographic features of
phase transformations in solids Progress in Materials
Science, 54:1101-1170.
2. Ali Y, Qiu D, Jiang B, Pan F-S, Zhang M-X (2016) The
influence of CaO addition on grain refinement of cast
magnesium alloys Scripta Materialia, 114:103-107.
3. Liu Z-L, Qiu D, Wang F, Taylor J, Zhang M-X (2015)
Crystallography of grain refinement in cast zinc-copper
alloys. Journal of Applied Crystallography 48:890-900.
4. Li M, Li J, Qiu D, Zheng Q, Wang G, Zhang M-X (2016)
Crystallographic study of grain refinement in low
and medium carbon steels. Philosophical Magazine
96:1556-1578.
5. Liu Z, Zhang Z, Jiang R, Li X, Zhang M-X, Qiu D (2016)
Crystallography of phase transformation in the self-
inclined InAs nanowires grown on GaAs{111} Scripta
Materialia, 121:79-83.
CRYSTALLOGRAPHY OF PHASE TRANSFORMATIONS IN
SOLIDS AND ITS APPLICATIONS
Mingxing Zhang
The University of Queensland, Australia
Mingxing Zhang, Struct Chem Crystallogr Commun 2018, Volume 4
DOI: 10.21767/2470-9905-C1-004