Crystal structure II Flashcards
Which mechanical properties depend on orientation with respect to crystallographic planes?
- brittle fracture
- elastic properties of crystals
- permanent deformation
- ductility
On which planes does brittle fracture occur at the scale of a single crystal?
Brittle fracture occurs on specific crystallographic planes.
What factor influences the elastic properties of crystals at the single-crystal scale?
The elastic properties of crystals depend on the direction of loading.
How does permanent deformation occur at the scale of a single crystal?
Permanent deformation occurs by sliding between crystal planes.
What is the relationship between the low ductility of magnesium and its crystal structure?
The low ductility of magnesium is related to the HCP (hexagonal close-packed) structure, which has low symmetry.
What are the three common crystallographic directions?
[111], [110] and [100] are
three common directions
Define anisotropic
Having different properties in different directions
Define isotropic
Properties are independent of direction
How can grain boundaries be visualized?
Microscopy
What constitutes grain boundaries in crystalline materials and what are they characterized by?
Grain boundaries constitute imperfect fit between grains, characterized by atomic disorder and high energy.
Where does nucleation occur during the solidification of polycrystalline materials?
Nucleation occurs at various locations
within melt
