Course detail

Dislocations and Plastic Deformation

FSI-WDD Acad. year: 2019/2020 Summer semester

Basic mechanisms of plastic deformation in metallic crystals, specific features of plastic deformation in macromolecular substances. A physics view of ceramic plasticity. Dislocation substructure of metallic and non-metallic crystals. Mechanisms of the interaction between dislocations and structural components (grain boundaries, subgrain boundaries, point defects, precipitates, etc.). Interaction between dislocations. Hardening and dehardening processes.

Language of instruction

Czech

Number of ECTS credits

5

Learning outcomes of the course unit

The knowledge of the processes of plastic deformation in crystals. Relation between sub-microscopic events in solids and macroscopic manifestation of these events – i.e. changes in mechanical properties.

Prerequisites

Atomic bonds, fundamentals of crystallography, crystallographic systems, crystal symmetry, crystal lattice defects, crystalline structure of solid solutions and intermediate phases in metallic and ceramic systems.

Planned learning activities and teaching methods

The course is taught through lectures explaining the basic principles and theory of the discipline. Teaching is suplemented by practical laboratory work.

Assesment methods and criteria linked to learning outcomes

Course-unit credit: Awarding the credit is conditional on attendance at all exercises and on written reports on the tasks assigned. Examination: In the written part, students answer four questions. Three questions are theoretical, one is practical. In this part of the exam, students may use available literature, with the exception of the course book. In the oral part, students explain the theoretical topics as prompted by the examiner.

Aims

The course concentrates on explaining the essence of the formation of mechanical properties of metallic and non-metallic substances, in dependence on faulted crystal lattice. Information is provided about the mechanisms of plastic deformation in single-crystal and polycrystalline materials, deformation textures, and strain hardening. In the exercises, students learn the experimental methods for studying plastic deformation.

Specification of controlled education, way of implementation and compensation for absences

Attendance at exercises is compulsory. Absence from exercises must be accounted for. Students who have missed an exercise will be given an extra assignment. They will prove in the form of a written report that they have mastered the given topic.

The study programmes with the given course

Type of course unit

 

Lecture

26 hours, optionally

Teacher / Lecturer

Syllabus

1. Crystallography of plastic deformation
2. Theory of critical slip stress
3. Process of strain hardening
4. Plastic deformation of non-metallic crystals
5. Dislocations
6. Slip plane, conservative and non-conservative motion of dislocations
7. Distribution of dislocations
8. Interaction between dislocations
9. Dislocations and grain boundaries (the Haal-Petch relation)
10. Dislocation sources
11. Partial dislocations
12. Stacking faults and their significance
13. Dislocations and allotropic transformation
14. Concluding the course and summarizing the most significant items of knowledge

Laboratory exercise

26 hours, compulsory

Teacher / Lecturer

Syllabus

1. Stereographic projection, orientation of crystals. 2. Reciprocal lattice (definition, application). 3. Radiographic methods of studying crystal orientation. 4. Methods for studying textures, pole figures. 5. Electron diffractography. 6. Methods for establishing dislocation density. 7. Metallography of dislocation substructure.