Volume 10, Issue 4s, November 2020

Special Issue on Grain Boundaries, Interfaces and Properties of Crystalline Materials

Preface

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Grain and interphase boundaries play an important, in some cases determining role in physical and mechanical properties of materials. At low temperatures they are barriers for dislocations and the interaction of dislocations and interfaces contributes greatly to the strength of crystals. At high temperatures the internal boundaries are the places of different processes determining the plasticity of materials such as diffusion, grain boundary sliding and migration, etc. Of a particular importance are the structures of interfaces and processes occurring there for the properties of nanocrystalline materials in which the interfaces occupy a considerable fraction of the volume. Furthermore, the development of new 2D materials such as graphene, posed the problem of broadening the concept of interfaces to these materials too. Thus, the study of the interfaces and their role in the material properties has always been at the forefront of Materials Science. In the latest decades, a great success has been achieved in the studies of grain boundaries and interfaces due to tremendous progresses in experimental equipment and techniques, computational tools and methods and the development of new materials. To outline at least a few of such successes, we have collected a few papers written by world-known researchers in the field as a special issue of the journal “Letters on Materials”.

As the editors of this special edition of Letters on Materials, we are sincerely grateful to all authors who have contributed papers to this special issue. Their cooperation and willingness have made the publication of this volume possible. Although all papers in this issue were invited, they were reviewed according to the standards of the journal. Therefore, the editors wish also to thank all the reviewers who have contributed to improvements in the papers.

Editors:

Louisette Priester, Université Paris Sud, Paris, France

Boris Straumal, Institute of Solid State Physics, Russian Academy of Sciences, Chernogolovka, Russia
Despite different atomic structures and degrees of symmetry of bcc and hcp crystals, the topological aspects of the processes of  growth and shrinkage of {112}bcc and {10-12}hcp deformation twins are equivalent.

On the common topological conditions for shear-coupled twin boundary migration in bcc and hcp metals

Despite different atomic structures and degrees of symmetry of bcc and hcp crystals, the topological aspects of the processes of growth and shrinkage of {112}bcc and {10-12}hcp deformation twins are equivalent.
A. Serra, N. Kvashin, N. Anento
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Year: 2020 Volume: 10     Issue: 4s Pages: 537-542


The transition from a direct to an inverse Hall-Petch dependence for nanocrystalline ceramics is related to an increase in the number density of triple junctions and dislocation emission from these junctions.

The role of grain boundaries and their triple junctions in strengthening and softening of nanocrystalline ceramics

The transition from a direct to an inverse Hall-Petch dependence for nanocrystalline ceramics is related to an increase in the number density of triple junctions and dislocation emission from these junctions.
A.G. Sheinerman, M.Y. Gutkin
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Year: 2020 Volume: 10     Issue: 4s Pages: 547-550