Quantitative Texture Analysis
4.1. Classic texture analysis
Before going into detail about quantitative texture description and analysis, we first need to introduce the basics of the classic texture analysis field, as opposed to the newer and more sophisticated “combined analysis” approach. Firstly, this introduction will help us to understand why “classic” scans used by diffractionists, such as θ-2θ or ω scans, are not able to provide quantitative information about texture, and often not even qualitative information. Secondly, the objects introduced will enable us to interpret and draw pole figures of typical textures. Thirdly, we will recognize why we generally need to calculate another object called OD or ODF, and not only pole figures, to unambiguously determine preferred orientations.
4.1.1. Qualitative aspects of texture analysis
Natural or artificial solids (rocks, ceramics, metals, alloys, biomaterials, etc.) are made up of aggregates of grains of different phases, sizes, shapes, stress states and orientations. Grains can be viewed at different scales, depending on the tool used to examine them.
Using metallurgical or geological optical microscopes, grains at the micrometer scale are visible, delimiting areas of different reflection or transmission of light. Since visible light is in a micrometer wavelength range, optics tell us the optical resolution is in the same order of range, and no detail about crystallographic lattices is made accessible, except where ...