At the macro scale all materials divide into isotropic and anisotropic. The former have constant and identical physical-mechanical properties in all directions, while the latter have different characteristics in different directions. Differences between isotropic and anisotropic materials arise due to differences in atom orientation in the crystal lattice. Let us consider the essence of each type and how this affects their application.
The word “isotropy” is formed by joining two words: “isos,” which in Greek means “equal,” and “tropos” — “way.” Isotropy is uniformity of physical-mechanical properties of materials in all directions. Examples of isotropic materials are metals, plastics, and glass.
Isotropic materials have identical physical, chemical, thermal, and electrical characteristics that do not depend on orientation. This means that applying force or pressure anywhere will not lead to a preferred direction of deformation. For example, if stress is applied to an isotropic material in any of the three spatial directions, it will behave the same. This makes isotropic materials convenient in many engineering solutions where uniformity of properties is required.
Anisotropic materials are characterized by their properties changing in different directions. This is linked to an asymmetric crystal structure in which certain material characteristics depend on a specific crystallographic direction.
An example of an anisotropic material is wood. When a mechanical force is applied to it, its behavior will differ depending on the direction of force application. Biological tissues, crystals, plant stems, and some composite materials are also examples of anisotropic materials.
Thanks to features of the crystal structure and the way grains form, metals are isotropic materials. Their crystal structure is characterized by regular repetition of atoms in space. In the metal structure atoms are ordered in a lattice consisting of many microscopic grains. Grains, in turn, consist of layers of atoms called lattice planes that can move relative to each other.
Isotropy of metals is due to their grains being oriented randomly in the material. Therefore, when force or pressure is applied to metal, it is distributed uniformly in all directions, as a result of which there is no preferred direction of deformation. This means metals have identical mechanical and physical characteristics in all directions.
However, during processing metals can become anisotropic and acquire a preferred direction of deformation as a result of various processes such as cold or hot rolling, stretching, casting, and others.
It is important that an alloy after processing retain its isotropy — sameness of mechanical and physical properties in all directions. This, in turn, will make it possible to manufacture metal parts and structures without accounting for their orientation in space.
In addition, any alloy must be homogeneous in its properties, which will make it possible to avoid uneven distribution of composition and structure inside it. This also prevents formation of weak spots or defects that may lead to material destruction or reduction of its quality and service characteristics.
At PZPS quality melting methods are used that make it possible to obtain chemically homogeneous ingots and, as a consequence, homogeneous strip, which is especially important in producing precision alloys:
Differences between isotropic and anisotropic materials play an important role in engineering design and industry. Understanding these concepts helps choose materials most suitable for specific service conditions, taking into account their mechanical, physical, and chemical characteristics in various directions.
To select an alloy matching your project requirements as closely as possible, call the listed phone or leave a request on the website. Our specialists will contact you and answer all questions in detail.
