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Tidefelt, Mattias
Publications (2 of 2) Show all publications
Tidefelt, M., Löstrand, J., Goetz, I. K., Donzel-Gargand, O., Ericsson, A., Han, X., . . . Fisk, M. (2024). In Situ Mapping of Phase Evolutions in Rapidly Heated Zr-Based Bulk Metallic Glass with Oxygen Impurities. Advanced Science, 11(16)
Open this publication in new window or tab >>In Situ Mapping of Phase Evolutions in Rapidly Heated Zr-Based Bulk Metallic Glass with Oxygen Impurities
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2024 (English)In: Advanced Science, E-ISSN 2198-3844, Vol. 11, no 16Article in journal (Refereed) Published
Abstract [en]

Metallic glasses exhibit unique mechanical properties. For metallic glass composites (MGC), composed of dispersed nanocrystalline phases in an amorphous matrix, these properties can be enhanced or deteriorated depending on the volume fraction and size distribution of the crystalline phases. Understanding the evolution of crystalline phases during devitrification of bulk metallic glasses upon heating is key to realizing the production of these composites. Here, results are presented from a combination of in situ small- and wide-angle X-ray scattering (SAXS and WAXS) measurements during heating of Zr-based metallic glass samples at rates ranging from 102 to 104 Ks-1 with a time resolution of 4ms. By combining a detailed analysis of scattering experiments with numerical simulations, for the first time, it is shown how the amount of oxygen impurities in the samples influences the early stages of devitrification and changes the dominant nucleation mechanism from homogeneous to heterogeneous. During melting, the oxygen rich phase becomes the dominant crystalline phase whereas the main phases dissolve. The approach used in this study is well suited for investigation of rapid phase evolution during devitrification, which is important for the development of MGC. Oxygen impurities impact on phase-transformations during rapid heating of Zr-based metallic glass Zr59.3Cu28.8Al10.4Nb1.5 is thoroughly investigated using a multi-technique approach. During devitrification, the extracted phase evolutions reveal that the phase fraction hierarchy correlates with the oxygen impurity concentration. Numerical simulations with a heterogeneous nucleation mode capture the experimental observations. During melting, the oxygen-rich phase becomes the dominant phase. image

Place, publisher, year, edition, pages
John Wiley & Sons, 2024
Keywords
additive manufacturing, AMLOY-ZR01, classical nucleation and growth theory, small-angle X-ray scattering, wide-angle X-ray scattering, transmission electron microscopy
National Category
Physical Sciences Materials Engineering
Identifiers
urn:nbn:se:mau:diva-66914 (URN)10.1002/advs.202307856 (DOI)001174897700001 ()38419373 (PubMedID)2-s2.0-85186239722 (Scopus ID)
Available from: 2024-04-25 Created: 2024-04-25 Last updated: 2024-04-25Bibliographically approved
Olsson, P. A., Awala, I., Holmberg-Kasa, J., Krause, A. M., Tidefelt, M., Vigstrand, O. & Music, D. (2023). Grain Size-Dependent Thermal Expansion of Nanocrystalline Metals. Materials, 16(14), Article ID 5032.
Open this publication in new window or tab >>Grain Size-Dependent Thermal Expansion of Nanocrystalline Metals
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2023 (English)In: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 16, no 14, article id 5032Article in journal (Refereed) Published
Abstract [en]

In the present work, we have used classical molecular dynamics and quantum mechanical density functional theory modeling to investigate the grain size-dependent thermal expansion coefficient (CTE) of nanocrystalline Cu. We find that the CTE increases by up to 20% with a gradually decreasing grain size. This behavior emerges as a result of the increased population of occupied anti-bonding states and bond order variation in the grain boundary regions, which contribute to thereduced resistance against thermally-induced bond stretching and dictate the thermal expansion behavior in the small grain size limit. As a part of the present work, we have established a procedure to produce ab initio thermal expansion maps that can be used for the prediction of the grain size dependent CTE. This can serve as a modeling tool, e.g., to explore the impact of grain boundary impurity segregation on the CTE.

Place, publisher, year, edition, pages
MDPI, 2023
Keywords
thermal expansion coefficient, nanocrystalline metals, molecular dynamics modeling, density functional theory modelling
National Category
Applied Mechanics Condensed Matter Physics
Identifiers
urn:nbn:se:mau:diva-62088 (URN)10.3390/ma16145032 (DOI)001039051900001 ()37512306 (PubMedID)2-s2.0-85166201596 (Scopus ID)
Funder
Swedish Research Council, 2018-04348Swedish Research Council, 2022-04497Olle Engkvists stiftelse, 217-0023
Available from: 2023-08-23 Created: 2023-08-23 Last updated: 2024-02-05Bibliographically approved
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