Special Issue "Crystallography of Structural Phase Transformations"

A special issue of Crystals (ISSN 2073-4352). This special issue belongs to the section "Crystalline Materials".

Deadline for manuscript submissions: 15 September 2020.

Special Issue Editor

Guest Editor
Dr. Cyril Cayron Website E-Mail
Swiss Federal Institute of Technology EPFL, Lausanne, Lausanne, Switzerland
Interests: metallurgy; EBSD; TEM; crystallography; martensitic transformations; twinning; variants; group theory

Special Issue Information

Dear Colleagues,

Solid-solid phase transformations generally imply a crystallographic orientation relationship (OR). The precipitates at the nucleation stage are often in OR with the surrounding matrix; the martensite products are in OR with their parent austenite; and the annealing twins and deformation twins are two crystals of the same species linked by an OR. The symmetries of the phases combined with the OR generate complex microstructures made of variants or twins that can be described mathematically with group theory, linear algebra, coset and multiple cosets, graphs, groupoids, or high-dimension spaces, etc. A lot of efforts have been devoted over the last century to establishing bridges between this “descriptive” crystallography and the “predictive” thermodynamics, but full unification remains to be achieved. For the moment, the models are not well balanced. On the crystallographic side, the phenomenological of theory of martensitic crystallography (PTMC), the edge-to-edge matching model, the disconnection “topological” model, etc. are well developed, but they are often limited to using the generalized Clausius–Clapeyron formula to make the link with thermodynamics. On the thermodynamic side, one can find the famous Landau and Ginzburg–Landau theories, but crystallographic complexity is often reduced to the symmetries of the polynomial form of the free energy introduced with group representation theory. It is not easy to find a way to marry all the different approaches, even if phase field has made a lot of progress over the last decades.

As it is important for research in this field to continue, all experimental and theoretical contributions about phase transformations and crystallography are welcome in this Special Issue, regardless of the type of materials (piezo and ferroelectrics, structurally hardened alloys, martensitic alloys, ordered alloys, shape memory alloys, polymorphic minerals, mechanically twinned materials, etc).

Dr. Cyril Cayron
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Crystals is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Phase transformation
  • Twins
  • Variants
  • Algebra
  • Orientation relationship

Published Papers (1 paper)

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Research

Open AccessArticle
Low-Temperature Polymorphic Transformation of β-Lactam Antibiotics
Crystals 2019, 9(9), 460; https://doi.org/10.3390/cryst9090460 - 02 Sep 2019
Abstract
Abstract: Polymorphic screening and transformation of molecular crystals are presently popular research areas in pharmaceutical studies. In this study, we developed an ab initio method to examine the structures, spectra, and stabilities of β-lactam (trans-13-azabicyclo[10.2.0]tetradecan-14-one), an important component of antibiotics. Based on [...] Read more.
Abstract: Polymorphic screening and transformation of molecular crystals are presently popular research areas in pharmaceutical studies. In this study, we developed an ab initio method to examine the structures, spectra, and stabilities of β-lactam (trans-13-azabicyclo[10.2.0]tetradecan-14-one), an important component of antibiotics. Based on the density functional theory (DFT) and second-order Møller-Plesset perturbation (MP2) methods, the present work demonstrated that forms I and II have isomorphic structures but can be distinguished by their Gibbs free energies and vibrational spectra. Forms I and II show a low-temperature polymorphic transformation at 308 K, where form I is stable below 308 K and form II is stable above 308 K. The proposed method suggests that the theoretical calculation can be used as a tool to effectively distinguish the isomorphic structures, and temperature-induced polymorphic transformation has far-reaching significance for drug storage and design. Full article
(This article belongs to the Special Issue Crystallography of Structural Phase Transformations)
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Planned Papers

The below list represents only planned manuscripts. Some of these manuscripts have not been received by the Editorial Office yet. Papers submitted to MDPI journals are subject to peer-review.

Title: Revisit the role of steps/disconnections on misfit cancellation at semi-coherent interface

—bridging the O-line model and the topological model

Author: Dong Qiu(RMIT University, Melbourne, VIC 3001, Australia)

Abstrsct: It has been a long-standing topic how the lattice misfit is cancelled at semi-coherent interphase boundary consisting of terraces and steps. Apart from a set of misfit dislocations separating the coherent patches, the role of steps (which is frequently called ‘disconnections’) on misfit cancellation remains some ambiguity because these steps do not destroy the continuity of lattice planes across the interface. This paper aims to clarify such ambiguity through identification of a set of secondary dislocations through a rigorous coincidence site lattice (CSL)/ complete pattern shift lattice (DSCL) analysis. A semi-coherent interface between body-centred cubic (BCC) Cr-rich precipitate and face-centred cubic (FCC) Cu-rich matrix that holds a near N-W orientation relationship (OR) is used as an example to demonstrate the procedure to determine the secondary dislocations that are coincident with steps along the interface. The current approach does not only redefine the disconnections in the topological model, but also extends the description of interfacial structure from the O-line model. As a result, the ‘discrepancy’ between these two popular crystallographic models can be completely eliminated when the interface is required to contain a pair of parallel close-packed directions.

Keywords: crystallography; interface; misfit dislocations; phase transformations

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