Lehrinhalte
Dislocations in ceramics show a surprising potential to alter functional properties of ceramics. At the same time, their mechanics is a complex topic and often dislocations are simply believed to not exist in or be irrelevant for ceramics. This lecture will review the difference in dislocation behavior in ceramics and metals requiring a completely different perspective. Furthermore, characterization techniques and a range of functional applications are presented.
Four blocks will be covered:
1) Basics of dislocations in ceramics: Slip systems, fundamental motion, specialties of dislocations in ionic crystals, typical features of dislocations, interaction of dislocations,
2) Characterization techniques: TEM, ECCI, EBSD, x-ray diffraction, etch-pits,
3) Dislocation mechanics in ceramics: Room-temperature plasticity, separation of: nucleation, motion and multiplication, thermally activated motion, plasticity of polycrystalline ceramics.
4) Functional properties: Core charge and compensating space charge, electrical conductivity, diffusion, thermal conductivity, optical properties, catalytic activity,
Literatur
1. Gottstein, G., Materialwissenschaft und Wekstofftechnik, Physikalische Grundlagen. 4th edition ed.; Spinger: 2014.
2. Hull, D.; Bacon, D. J., Introduction to Dislocations, Fifth Edition. Elsevier: 2011.
3. Rösler, J.; Haders, H.; Bäker, M., Mechanical Behavior of Engineering Materials. Springer: 2019.
4. Anderson, P. M.; Hirth, J. P.; Lothe, J., Theory of Dislocations. Third edition ed.; Cambridge University Press: New York, 2017.
5. Messerschmidt, U., Dislocation Dynamics during Plastic Deformation. Springer: New York, NY, USA, 2010; Vol. 129.
6. Gilman, J. J.; Johnston, W. G., Dislocations in Lithium Fluoride Crystals. Solid State Phys 1962, 13, 147-222.
7. Whitworth, R. W., Charged Dislocations in Ionic-Crystals. Advances in Physics 1975, 24, (2), 203-304.
Voraussetzungen
(optional) Materialwissenschaft IV: (Mechanical behavior of Materials)
(optional) Materialwissenschaft III: (Defects in crystalline solids)
Offizielle Kursbeschreibung
The students will be introduced to both the functional and mechanical the role of dislocations in ceramics. Their strain field, core charge and compensating space charge allow to alter functional properties ranging from conductivity over the band gap to catalytic activity. The 1-dimensional nature adds geometrical complexity but also design opportunities. Surprisingly many ceramics (single crystals) are ductile at room temperature and even polycrystals can be deformed at elevated temperature. Yet the mechanical behavior requires a different perspective than plasticity in metals. This course ais to prepare students to independently navigate the research field of dislocations in ceramics.
Online-Angebote
moodle
Dislocations in ceramics show a surprising potential to alter functional properties of ceramics. At the same time, their mechanics is a complex topic and often dislocations are simply believed to not exist in or be irrelevant for ceramics. This lecture will review the difference in dislocation behavior in ceramics and metals requiring a completely different perspective. Furthermore, characterization techniques and a range of functional applications are presented.
Four blocks will be covered:
1) Basics of dislocations in ceramics: Slip systems, fundamental motion, specialties of dislocations in ionic crystals, typical features of dislocations, interaction of dislocations,
2) Characterization techniques: TEM, ECCI, EBSD, x-ray diffraction, etch-pits,
3) Dislocation mechanics in ceramics: Room-temperature plasticity, separation of: nucleation, motion and multiplication, thermally activated motion, plasticity of polycrystalline ceramics.
4) Functional properties: Core charge and compensating space charge, electrical conductivity, diffusion, thermal conductivity, optical properties, catalytic activity,
Literatur
1. Gottstein, G., Materialwissenschaft und Wekstofftechnik, Physikalische Grundlagen. 4th edition ed.; Spinger: 2014.
2. Hull, D.; Bacon, D. J., Introduction to Dislocations, Fifth Edition. Elsevier: 2011.
3. Rösler, J.; Haders, H.; Bäker, M., Mechanical Behavior of Engineering Materials. Springer: 2019.
4. Anderson, P. M.; Hirth, J. P.; Lothe, J., Theory of Dislocations. Third edition ed.; Cambridge University Press: New York, 2017.
5. Messerschmidt, U., Dislocation Dynamics during Plastic Deformation. Springer: New York, NY, USA, 2010; Vol. 129.
6. Gilman, J. J.; Johnston, W. G., Dislocations in Lithium Fluoride Crystals. Solid State Phys 1962, 13, 147-222.
7. Whitworth, R. W., Charged Dislocations in Ionic-Crystals. Advances in Physics 1975, 24, (2), 203-304.
Voraussetzungen
(optional) Materialwissenschaft IV: (Mechanical behavior of Materials)
(optional) Materialwissenschaft III: (Defects in crystalline solids)
Offizielle Kursbeschreibung
The students will be introduced to both the functional and mechanical the role of dislocations in ceramics. Their strain field, core charge and compensating space charge allow to alter functional properties ranging from conductivity over the band gap to catalytic activity. The 1-dimensional nature adds geometrical complexity but also design opportunities. Surprisingly many ceramics (single crystals) are ductile at room temperature and even polycrystals can be deformed at elevated temperature. Yet the mechanical behavior requires a different perspective than plasticity in metals. This course ais to prepare students to independently navigate the research field of dislocations in ceramics.
Online-Angebote
moodle
- Lehrende: Joachim Brötz
- Lehrende: Enrico Bruder
- Lehrende: Xufei Fang
- Lehrende: Till Frömling
- Lehrende: Jürgen Rödel
Semester: SoSe 2021