Microstructure

Abstract

The constitution of ferrous materials shown in phase diagrams describes the type and quantities of the phases that are in thermodynamic equilibrium; however, it does not provide any information on their appearance and spatial distribution. These morphological aspects are grouped together under the term ’microstructure’, which comprises building blocks of the different phases. These building blocks are joined together through their interfaces. They contain disordering and are also affected by anisotropy and segregation. The near-equilibrium microstructure created by slow temperature changes may be completely different from a non-equilibrium microstructure such as that produced by rapid self-cooling of a laser-welded seam or that intentionally obtained by quenching after a heat treatment process.