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Texture

Texture: Crystallographic Texture
Definition:Distribution of crystallographic orientations of a polycrystalline specimen.
Explanation:The orientations of grains in a polycrystalline material are rarely randomly distributed. The grains show typically preferred orientations that result from the processing history of the material. The distribution of these crystallographic orientations is known as texture. The texture is very important, since all anisotropic material properties, such as mechanical strength, ductility, Young´s Modulus, etc. are dependent on texture. Hence, required material properties can be tailored by adjusting a certain texture.

Crystallographic texture can be divided into macrotexture and microtexutre. The former describes the statistical orientation distribution obtained from measuring a large amount of grains. It reflects an average value of volume fractions of a specimen having the same orientation and does not give any localized information about the relation of microstructure and texture. On the other hand, microtexture describes the orientation distribution including the spatial location of the grains, providing auxiliary information about e.g. local property effects and grain boundary character/distribution.

Crystallographic textures can be obtained by e.g. X-ray diffraction (macrotexture) or electron backscatter diffraction (→EBSD) (microtexture) and are usually expressed by using pole figures and/or orientation distribution functions (→ORD).
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(a) Sharp texture: grains show preferred orientation. (b) Random texture: grain orientations are randomly distributed.
SFB-Link:The investigation and control of the crystallographic texture of high manganese steels is of particular interest as it determines the anisotropy of materials’ properties. Moreover, careful analysis of the texture evolution during processing is necessary to gain further understanding of the underlying mechanisms, e.g. deformation, nucleation or grain growth mechanisms (→ClaNG).
References:V. Randle und O. Engler, Introduction to Texture Analysis, CRC Press, 2000