Please use this identifier to cite or link to this item: http://hdl.handle.net/10995/118379
Title: A general model for the crystal structure of orthorhombic martensite in Ti alloys
Authors: Demakov, S.
Kylosova, I.
Stepanov, S.
Bönisch, M.
Issue Date: 2021
Publisher: International Union of Crystallography
Citation: A general model for the crystal structure of orthorhombic martensite in Ti alloys / S. Demakov, I. Kylosova, S. Stepanov et al. // Acta Crystallographica Section B: Structural Science, Crystal Engineering and Materials. — 2021. — Vol. 77. — P. 749-762.
Abstract: The present work develops a novel unified approach to describe the crystal structure of orthorhombic martensite (α′′) in Ti alloys independent of chemical composition. By employing a straightforward yet highly instructive solid sphere model for the basic tetrahedral structural unit the crystal structures involved in the β ↔ α′′/α′ martensitic transformation are categorized into several intermediate configurations. Importantly, a new metric is introduced, δ, which unambiguously characterizes the atomic positions inside the orthorhombic unit cell depending on unit-cell geometry. Furthermore, the exclusive use of relative quantities to describe unit-cell geometry and atom positions renders the approach developed herein independent of alloy content. In this way, shortcomings of commonly suggested structural metrics for α′′ are eliminated. Subsequently, the novel methodology is applied to analyse and compare the crystal structure of α′′ across a broad range of Ti alloys based on experimentally measured unit-cell parameters. From this analysis it emerges that a large fraction of structural configurations along the b.c.c.-Cmcm-h.c.p. transformation path is not observed in quenched alloys. The threshold between the not-observed and the remaining well observed configurations is identified with an ideal Cmcm crystal structure, relative to which the experimentally found α′′ is compressed along its c axis. © 2021 International Union of Crystallography. All rights reserved.
Keywords: CRYSTAL STRUCTURE
MARTENSITIC TRANSFORMATION
TI ALLOYS
TRANSFORMATION STRAIN
CELLS
CYTOLOGY
MARTENSITE
MARTENSITIC TRANSFORMATIONS
TITANIUM ALLOYS
CELL GEOMETRIES
CHEMICAL COMPOSITIONS
CRYSTALS STRUCTURES
GENERAL MODEL
ORTHORHOMBIC MARTENSITE
SOLID SPHERES
TI ALLOYS
TRANSFORMATION STRAIN
UNIFIED APPROACH
UNIT CELLS
CRYSTAL STRUCTURE
URI: http://hdl.handle.net/10995/118379
Access: info:eu-repo/semantics/openAccess
SCOPUS ID: 85116857882
ISSN: 20525192
DOI: 10.1107/S2052520621007976
metadata.dc.description.sponsorship: 0836-2020-0020
The following funding is acknowledged: State Assignment of Russian Federation (grant 0836-2020-0020).
Appears in Collections:Научные публикации, проиндексированные в SCOPUS и WoS CC

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