Material is a substance or mixture of substances that constitutes an

object Object may refer to: General meanings * Object (philosophy), a thing, being, or concept ** Object (abstract), an object which does not exist at any particular time or place ** Physical object, an identifiable collection of matter * Goal, an ...

. Materials can be pure or impure, living or non-living matter. Materials can be classified on the basis of their physical and

chemical properties A chemical property is any of a material's properties that becomes evident during, or after, a chemical reaction; that is, any quality that can be established only by changing a substance's chemical identity.William L. Masterton, Cecile N. Hurley, ...

, or on their

geological Geology () is a branch of natural science concerned with Earth and other astronomical objects, the features or rocks of which it is composed, and the processes by which they change over time. Modern geology significantly overlaps all other E ...

origin or biological function. Materials science is the study of materials, their properties 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 Industry may refer to: Economics * Industry (economics), a generally categorized branch of economic activity * Industry (manufacturing), a specific branch of economic activity, typically in factories with machinery * The wider industrial sector ...

, materials are inputs to

manufacturing processes Manufacturing is the creation or production of goods with the help of equipment, labor, machines, tools, and chemical or biological processing or formulation. It is the essence of secondary sector of the economy. The term may refer to a rang ...

to produce products or more complex materials.

Historical elements

Materials chart the history of humanity. The system of the three prehistoric ages ( Stone Age,

Bronze Age The Bronze Age is a historic period, lasting approximately from 3300 BC to 1200 BC, characterized by the use of bronze, the presence of writing in some areas, and other early features of urban civilization. The Bronze Age is the second prin ...

Iron Age The Iron Age is the final epoch of the three-age division of the prehistory and protohistory of humanity. It was preceded by the Stone Age ( Paleolithic, Mesolithic, Neolithic) and the Bronze Age ( Chalcolithic). The concept has been mostl ...

) were succeeded by historical ages: steel age in the 19th century, polymer age in the middle of the following century (plastic age) and silicon age in the second half of the 20th century.

Classification by use

Materials can be broadly categorized in terms of their use, for example: *

Building material Building material is material used for construction. Many naturally occurring substances, such as clay, rocks, sand, wood, and even twigs and leaves, have been used to construct buildings. Apart from naturally occurring materials, many man-ma ...

s are used for construction *

Building insulation materials Building insulation materials are the building materials which form the thermal envelope of a building or otherwise reduce heat transfer. Insulation may be categorized by its composition (natural or synthetic materials), form (batts, blankets, loo ...

are used to retain heat within buildings *

Refractory materials In materials science, a refractory material or refractory is a material that is resistant to decomposition by heat, pressure, or chemical attack, and retains strength and form at high temperatures. Refractories are polycrystalline, polyphase, ...

are used for high-temperature applications *

Nuclear materials Nuclear material refers to the metals uranium, plutonium, and thorium, in any form, according to the IAEA. This is differentiated further into "source material", consisting of natural and depleted uranium, and "special fissionable material", co ...

are used for nuclear power and weapons *

Aerospace materials Aerospace materials are materials, frequently metal alloys, that have either been developed for, or have come to prominence through their use for aerospace purposes. These uses often require exceptional performance, strength or heat resistance, ev ...

are used in aircraft and other aerospace applications *

Biomaterial A biomaterial is a substance that has been engineered to interact with biological systems for a medical purpose, either a therapeutic (treat, augment, repair, or replace a tissue function of the body) or a diagnostic one. As a science, biomateria ...

s are used for applications interacting with living systems

Material selection Material selection is a step in the process of designing any physical object. In the context of product design, the main goal of material selection is to minimize cost while meeting product performance goals. Systematic selection of the best materi ...

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: *

Ceramic A ceramic is any of the various hard, brittle, heat-resistant and corrosion-resistant materials made by shaping and then firing an inorganic, nonmetallic material, such as clay, at a high temperature. Common examples are earthenware, porcelain ...

s: non-metal, inorganic solids *

Glass Glass is a non-crystalline, often transparent, amorphous solid that has widespread practical, technological, and decorative use in, for example, window panes, tableware, and optics. Glass is most often formed by rapid cooling ( quenching ...

es: amorphous

solids Solid is one of the four fundamental states of matter (the others being liquid, gas, and plasma). The molecules in a solid are closely packed together and contain the least amount of kinetic energy. A solid is characterized by structural ...

Metals A metal (from Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. Metals are typical ...

: pure or combined chemical elements with specific chemical bonding behavior *

Polymers A polymer (; Greek '' poly-'', "many" + ''-mer'', "part") is a substance or material consisting of very large molecules called macromolecules, composed of many repeating subunits. Due to their broad spectrum of properties, both synthetic an ...

: materials based on long carbon or silicon chains * Hybrids: combinations of multiple materials, for example composites.

Larger-scale structure

metamaterial A metamaterial (from the Greek word μετά ''meta'', meaning "beyond" or "after", and the Latin word ''materia'', meaning "matter" or "material") is any material engineered to have a property that is not found in naturally occurring materials. ...

is any material engineered to have a property that is not found in naturally occurring materials, usually by combining several materials to form a composite and / or tuning the

shape A shape or figure is a graphical representation of an object or its external boundary, outline, or external surface, as opposed to other properties such as color, texture, or material type. A plane shape or plane figure is constrained to lie ...

geometry Geometry (; ) is, with arithmetic, one of the oldest branches of mathematics. It is concerned with properties of space such as the distance, shape, size, and relative position of figures. A mathematician who works in the field of geometry is ...

size Size in general is the magnitude or dimensions of a thing. More specifically, ''geometrical size'' (or ''spatial size'') can refer to linear dimensions ( length, width, height, diameter, perimeter), area, or volume. Size can also be m ...

orientation Orientation may refer to: Positioning in physical space * Map orientation, the relationship between directions on a map and compass directions * Orientation (housing), the position of a building with respect to the sun, a concept in building de ...

and arrangement to achieve the desired property. In

foams Foams are materials formed by trapping pockets of gas in a liquid or solid. A bath sponge and the head on a glass of beer are examples of foams. In most foams, the volume of gas is large, with thin films of liquid or solid separating the ...

and textiles, the chemical structure is less relevant to immediately observable

properties Property is the ownership of land, resources, improvements or other tangible objects, or intellectual property. Property may also refer to: Mathematics * Property (mathematics) Philosophy and science * Property (philosophy), in philosophy an ...

than larger-scale material features: the holes in foams, and the weave in textiles.

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: * Stiffness *

Strength Strength may refer to: Physical strength *Physical strength, as in people or animals * Hysterical strength, extreme strength occurring when people are in life-and-death situations *Superhuman strength, great physical strength far above human c ...

Toughness In materials science and metallurgy, toughness is the ability of a material to absorb energy and plastically deform without fracturing.Hardness In materials science, hardness (antonym: softness) is a measure of the resistance to localized plastic deformation induced by either mechanical indentation or abrasion. In general, different materials differ in their hardness; for example hard ...

Thermal properties

Materials may degrade or undergo changes of properties at different temperatures. Thermal properties also include the material's

thermal conductivity The thermal conductivity of a material is a measure of its ability to conduct heat. It is commonly denoted by k, \lambda, or \kappa. Heat transfer occurs at a lower rate in materials of low thermal conductivity than in materials of high thermal ...

and

heat capacity Heat capacity or thermal capacity is a physical property of matter, defined as the amount of heat to be supplied to an object to produce a unit change in its temperature. The SI unit of heat capacity is joule per kelvin (J/K). Heat capacity ...

, relating to the transfer and storage of

thermal energy The term "thermal energy" is used loosely in various contexts in physics and engineering. It can refer to several different well-defined physical concepts. These include the internal energy or enthalpy of a body of matter and radiation; heat, de ...

by the material.

Other properties

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

References

External links

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