ABSTRACT
Basically three different types of interface are important in metallic systems:
1. The free surfaces of a crystal (solid/vapour interface) 2. Grain boundaries (α/α interfaces) 3. Interphase interfaces (α/γ interfaces)
All crystals possess the rst type of interface. The second type separates crystals with essentially the same composition and crystal structure, but a different orientation in space. The third interface separates two different phases that can have different crystal structures and/or compositions and therefore also includes solid/liquid interfaces.
