In order to understand how crystallographic textures are formed and how they effect properties in aluminium alloys, it is essential to have a method of representing, or characterising them.

Many material characteristics or properties such as density, Young modulus or electrical resistivity can be described by a single numeric value.

Crystallographic texture however is necessarily more complex as it describes the orientations in 3D space of thousands or millions of individual grains. We therefore represent it graphically, and have two important tools to do this.

• the pole figure, based on the stereographic projection.
• the Orientation Distribution Function (ODF), based on the three Euler angles of rotation required to co-orientate a unit cell with a reference coordinate system.

Over the next few pages, each will be described with the aid of interactive figures and diagrams.