Kalcher, Constanze (2019)
Creep of Cu-Zr metallic glasses and metallic glass composites: A molecular dynamics study.
Technische Universität Darmstadt
Dissertation, Erstveröffentlichung
Kurzbeschreibung (Abstract)
Creep is the time-dependent deformation of a material at elevated temperature and under stress-conditions below yield. This slow, time-delayed deformation can ultimately lead to the failure of an engineering component, especially in high-temperature applications. But even well before material failure, the elongation of an engineering component, e.g. a turbine blade, during service life can have catastrophic consequences. Thus, knowledge of the mechanism of creep deformation is of utmost importance for choosing a material for a specific engineering application. While the phenomenon of creep is already well understood in metals and a large body of work exists on how to improve their creep resistance, this behavior is not exclusive to crystalline materials. Partly crystalline materials such as polymers and ceramics and even glasses can exhibit significant creep deformation as well. For the conventional soda-lime glass the possibility of creep seems irrelevant in its typical application window, but with the development of new glassy materials, such as metallic glasses, that are amorphous metals quenched from the melt and potential candidates for a wide application range of temperatures and stresses, the assessment of the creep behavior of amorphous materials has been taken beyond purely scientific interest. In this thesis molecular dynamics simulations are used to understand the creep behavior of a homogeneous Cu_{64}Zr_{36} metallic glass as well as glass-crystal composites. First, we treat the case of the homogeneous glass, and establish the temperature and stress parameter range necessary to observe creep in molecular dynamics simulations. Second, we will study the influence of the glass-crystal interface properties on the creep rates. The latter also critically depends on how realistic the computer composite model is.Third, we study a different microstructure of amorphous-crystalline composites which belong to the nanoglass family. We show how the glassy grain-boundary phase present in a nanoglass can be altered to have a reinforcing effect, both in the low temperature regime and under creep conditions.
| Typ des Eintrags: | Dissertation | ||||
|---|---|---|---|---|---|
| Erschienen: | 2019 | ||||
| Autor(en): | Kalcher, Constanze | ||||
| Art des Eintrags: | Erstveröffentlichung | ||||
| Titel: | Creep of Cu-Zr metallic glasses and metallic glass composites: A molecular dynamics study | ||||
| Sprache: | Englisch | ||||
| Referenten: | Albe, Prof. Dr. Karsten ; Bitzek, Prof. Dr. Erik | ||||
| Publikationsjahr: | 17 April 2019 | ||||
| Ort: | Darmstadt | ||||
| Datum der mündlichen Prüfung: | 3 Dezember 2018 | ||||
| URL / URN: | https://tuprints.ulb.tu-darmstadt.de/8610 | ||||
| Kurzbeschreibung (Abstract): | Creep is the time-dependent deformation of a material at elevated temperature and under stress-conditions below yield. This slow, time-delayed deformation can ultimately lead to the failure of an engineering component, especially in high-temperature applications. But even well before material failure, the elongation of an engineering component, e.g. a turbine blade, during service life can have catastrophic consequences. Thus, knowledge of the mechanism of creep deformation is of utmost importance for choosing a material for a specific engineering application. While the phenomenon of creep is already well understood in metals and a large body of work exists on how to improve their creep resistance, this behavior is not exclusive to crystalline materials. Partly crystalline materials such as polymers and ceramics and even glasses can exhibit significant creep deformation as well. For the conventional soda-lime glass the possibility of creep seems irrelevant in its typical application window, but with the development of new glassy materials, such as metallic glasses, that are amorphous metals quenched from the melt and potential candidates for a wide application range of temperatures and stresses, the assessment of the creep behavior of amorphous materials has been taken beyond purely scientific interest. In this thesis molecular dynamics simulations are used to understand the creep behavior of a homogeneous Cu_{64}Zr_{36} metallic glass as well as glass-crystal composites. First, we treat the case of the homogeneous glass, and establish the temperature and stress parameter range necessary to observe creep in molecular dynamics simulations. Second, we will study the influence of the glass-crystal interface properties on the creep rates. The latter also critically depends on how realistic the computer composite model is.Third, we study a different microstructure of amorphous-crystalline composites which belong to the nanoglass family. We show how the glassy grain-boundary phase present in a nanoglass can be altered to have a reinforcing effect, both in the low temperature regime and under creep conditions. |
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| URN: | urn:nbn:de:tuda-tuprints-86102 | ||||
| Sachgruppe der Dewey Dezimalklassifikatin (DDC): | 500 Naturwissenschaften und Mathematik > 500 Naturwissenschaften 500 Naturwissenschaften und Mathematik > 530 Physik |
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| Fachbereich(e)/-gebiet(e): | 11 Fachbereich Material- und Geowissenschaften 11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft 11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft > Fachgebiet Materialmodellierung Zentrale Einrichtungen Zentrale Einrichtungen > Hochschulrechenzentrum (HRZ) Zentrale Einrichtungen > Hochschulrechenzentrum (HRZ) > Hochleistungsrechner |
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| Hinterlegungsdatum: | 28 Apr 2019 19:55 | ||||
| Letzte Änderung: | 28 Apr 2019 19:55 | ||||
| PPN: | |||||
| Referenten: | Albe, Prof. Dr. Karsten ; Bitzek, Prof. Dr. Erik | ||||
| Datum der mündlichen Prüfung / Verteidigung / mdl. Prüfung: | 3 Dezember 2018 | ||||
| Export: | |||||
| Suche nach Titel in: | TUfind oder in Google | ||||
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