MODULE 2 - Introduction to
Basic Crystallography
•
Bravais Lattices
•
Crystal system
•
Miller Indices
•
Crystallographic Direction
•
Zone Axis
•
Zones in the EBSP
Determining the Orientation
•
Indexing
Describing Orientations
•
Euler Angle
•
Euler Space - ODF's
•
Orientation Matrix
•
Ideal Orientation Nomenclature
•
Misorientation
Crystal Forms
Describing Planes and
Directions
Describing Misorientations
Introduction to Basic Crystallography Bravais Lattices
• There are 14 Bravais Lattices:
Note:
• Body Centered
Cubic (BCC) and
• Face Centred
Cubic (FCC)
forms
• From these 7 crystal systems are derived
Introduction to Basic Crystallography Crystal System
• These terms describe the geometry of the unit cell - the
structure that is repeated throughout the crystal.
• There are seven Crystal systems:
1. Cubic
2. Hexagonal
3. Trigonal
4. Tetragonal
5. Orthorhombic
6. Monoclinic
7. Triclinic
The lengths of the sides of the unit cell are shown below as a, b and c. The
corresponding angles are shown as alpha, beta and gamma.
Introduction to Basic Crystallography - Miller
Indices
• For a cubic
example, Miller
indices can be
derived to describe
a plane
• Consider a cubic
unit cell with sides a
b, c, with an origin
as shown
Introduction to Basic Crystallography Crystallographic Direction
• A crystallographic direction describes the intersection of
specific faces or lattice planes
• Miller Indices can be used to describe directions
For a cubic material the plane and the normal to the
plane have the same indices
Introduction to Basic Crystallography - Zone
Axis
• ‘Zone’: faces or
planes in a crystal
with parallel
intersections.
• Zone Axis: The
common direction of
the intersections