Material


A material is a substance or mixture of substances that constitutes an object. Materials can be pure or impure, living or non-living matter. Materials can be classified based on their physical and chemical properties, or on their geological origin or biological function. Material science is the study of materials and their applications.
Raw materials can be processed in different ways to influence their properties, by purification, shaping or the introduction of other materials. New materials can be produced from raw materials by synthesis.
In industry, materials are inputs to manufacturing processes to produce products or more complex materials.

Classification by use

Materials can be broadly categorised in terms of their use, for example:
Material selection is a process to determine which material should be used for a given application.

Classification by structure

The relevant structure of materials has a different length scale depending on the material. The structure and composition of a material can be determined by microscopy or spectroscopy.

Microstructure

In engineering, materials can be categorised according to their microscopic structure:
In foams and textiles, the chemical structure is less relevant to immediately observable properties than larger-scale material features: the holes in foams, and the weave in materials.

Classification by properties

Materials can be compared and classified by their large-scale physical properties.

Mechanical properties

Mechanical properties determine how a material responds to applied forces.
Examples include:
Materials may degrade or undergo changes of properties at different temperatures. Thermal properties also include the material's thermal conductivity and heat capacity, relating to the transfer and storage of thermal energy by the material.

Other properties

Materials can be compared and categorised by any quantitative measure of their behavior under various conditions. Notable additional properties include the optical, electrical and magnetic behavior of materials.