Crystal defects always exist in metals and alloys. They should not be seen as something deleterious, or to be suppressed. Instead, metallurgists can use them to optimise the properties of metals, especially mechanical properties: for example, metals can be strengthened by introducing more dislocations or grain boundaries. In addition, defects impact a lot the diffusion properties of metals, that are essential to the understanding of materials ageing.
This lecture gives an in-depth description of crystals defects and how they affect the properties and behaviour of materials.
Outline of the lecture:
1. Crystals defects
1.1 Point defects
1.2 Dislocations
1.3 Grain boundaries
2. Physics of plastic deformation
2.1 Dislocations/obstacle interactions
2.2 Monotonic and cyclic plasticity
2.3 Mechanisms of creep
3. Solid state diffusion
3.1 Macroscale approach (Fick's equations)
3.2 Mechanisms of diffusion
4. Surface and interfaces in materials
4.1 Basics of surface physics and chemistry
4.2 Oxidation
4.2 Interface segregation
5. Mechanisms of crystallographic texture formation
| On completion of the unit, the student will be capable of: | Classification level | Priority |
|---|---|---|
| Know the types of crystal defects (point, linear and planar defects) | 1. Knowledge | Essential |
| Determine concentrations of defects | 4. Analyse | Essential |
| Describe interactions between defects | 4. Analyse | Essential |
| Show quantitatively how crystal defects impact properties | 4. Analyse | Essential |
| Describe the mechanisms of plastic deformation at the scale of one or several crystals | 1. Knowledge | Essential |
| Describe the mechanisms of solid state diffusion and how it affects possible degradation mechanisms (oxidation, segregation, ageing). | 1. Knowledge | Essential |
| Calculate concentration profiles, diffusion times, diffusion distances | 4. Analyse | Essential |
| Describe the mechanisms of crystallographic texture formation | 1. Knowledge | Essential |
| Percentage ratio of individual assessment | Percentage ratio of group assessment | ||||
|---|---|---|---|---|---|
| Written exam: | 70 | % | Project submission: | % | |
| Individual oral exam: | % | Group presentation: | % | ||
| Individual presentation: | % | Group practical exercise: | % | ||
| Individual practical exercise: | 30 | % | Group report: | % | |
| Individual report: | % | ||||
| Other(s): % | |||||
| Type of teaching activity | Content, sequencing and organisation |
|---|---|
| Lecture and tutorials | 50 hours |
| Practical work | 20 hours |