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DESCRIPTION OF MICROSTRUTURE

Microstructure can include all of the features of internal

structure of heterogeneous materials at a variety of length

scales.

(e.g. phase, grain size, lattice orientation, dislocation, voids, interatomic spacing) 10-8 m

10-10 m

10-7 m

10-5 m

10-3 m

The crystal orientation, g, can be defined by a set of three rotations (φ1, Φ, φ2) that relate the crystal frame to the sample reference frame.

X

Z

Y

[001]

[010]

[100]

crystalg

The distribution of crystal lattice orientations in a polycrystalline metal (also referred to as texture or ODF) is taken as the main descriptor of microstructure.

Projections: Pole Figures (PF) Orientations can be plotted as a two dimensional projections.

A pole figure of pole relative to the sample reference frame.

Example: (001) pole figure.

Note that the three point shown in the pole figure are three symmetrically equivalent planes in

the crystal. (The clear points correspond to point extending into the bottom half of the sphere.

Projections: Inverse Pole Figure (IPF)

An inverse pole figure shows the position of a sample

direction relative to the crystal reference frame.

Example: [001] inverse pole figure.

Note because of the symmetry in the crystal, multiple points appear on the full IPF. If the

IPF is plotted using the unit triangle, then only one point per orientation will appear in the

plot.