What does 'microstructure' refer to in materials science?

The term 'microstructure' in materials science specifically refers to the structure of a material at the microscopic scale. This includes the arrangement and organization of the grains, phases, and other microstructural features that can influence the material's properties and behavior, such as strength, ductility, and thermal conductivity. Analyzing the microstructure often involves techniques like microscopy that help scientists and engineers understand how the internal features of a material contribute to its overall performance.

While the atomic arrangement within a crystal pertains to the fundamental structural aspects of a material, it is typically more focused on the atomic scale rather than the larger, observable features that would be examined at the micro level. The total composition of a material refers to the chemical makeup, which gives context but does not directly describe the way that composition is structured on a microscopic scale. Similarly, the surface finish of a material pertains to the external characteristics and texture rather than the internal structure. Thus, the choice that encapsulates the definition of microstructure most accurately is the one that addresses the organization of features at the microscopic scale.