Materials science

Materials science is a multi-disciplinary field involving the properties of matter and its applications to various areas of science and engineering. It includes elements of applied physics and chemistry, as well as chemical, mechanical, civil and electrical engineering. With significant media attention to nanoscience and nanotechnology in the recent years, materials science has been propelled to the forefront at many universities, sometimes controversially.

History

The choice material of a given era is often its defining point: the stone age, bronze age, and steel age are examples. Materials science is one of the oldest forms of engineering and applied science. Modern materials science evolved directly from metallurgy, which itself evolved from mining. A major breakthrough in the understanding of materials occurred in the late 19th century, when Willard Gibbs demonstrated that thermodynamic properties relating to atomic structure in various phases are related to the physical properties of the material. Important elements of modern materials science are a product of the space race: the understanding and engineering of the metallic alloys and other materials that went into the construction of space vehicles was one of the enablers of space exploration. Materials science has driven, and been driven by, the development of revolutionary technologies such as plastics, semiconductors, and biomaterials.

Before the 1960s (and in some cases decades after), many materials science departments were named metallurgy departments, from a 19th and early 20th century emphasis on metals. The field has since broadened to include every class of materials, including: ceramics, polymers, semiconductors, magnetic materials, and biological materials such as medical implants.

Fundamentals of Materials Science

In materials science, rather than haphazardly looking for and discovering materials and exploiting their properties, one instead aims to understand materials fundamentally so that new materials with the desired properties can be created.

The basis of all materials science involves relating the desired properties and relative performance of a material in a certain application to the structure of the atoms and phases in that material through characterization. The major determinants of the structure of a material and thus of its properties are its constituent chemical elements and the way in which it has been processed into its final form. These, taken together and related through the laws of thermodynamics, govern the material’s microstructure, and thus its properties.

An old adage in materials science says: "materials are like people; it is the defects that make them interesting". The manufacture of a perfect crystal of a material is physically impossible. Instead materials scientists manipulate the defects in crystalline materials such as precipitates, grain boundaries (Hall-Petch relationship), interstitial atoms, vacancies or substitutional atoms, creating a material with the desired properties.

Not all materials have a regular crystal structure. Polymers display varying degrees of crystallinity. Glasses, some ceramics, and many natural materials are amorphous, not possessing any long-range order in their atomic arrangements. These materials are much harder to engineer than crystalline materials. Polymers are a mixed case, and their study commonly combines elements of chemical and statistical thermodynamics to give thermodynamical, rather than mechanical descriptions of physical properties.

Materials in Industry

Radical materials advances can drive the creation of new products or even new industries, but stable industries also employ materials scientists to make incremental improvements and troubleshoot issues with currently used materials. Industrial applications of materials science include materials design, cost-benefit tradeoffs in industrial production of materials, processing techniques (casting, rolling, welding, ion implantation, crystal growth, thin-film deposition, sintering, glassblowing, etc.), and analytical techniques (characterization techniques such as electron microscopy, x-ray diffraction, calorimetry, nuclear microscopy (HEFIB), Rutherford backscattering, neutron diffraction, etc.).

The overlap between physics and materials science has led to the offshoot field of materials physics, which is concerned with the physical properties of materials. The approach is generally more macroscopic and applied than in condensed matter physics. See the important publications in materials physics for more details on this field of study.

Classes of materials (by bond types)

Materials science encompasses various classes of materials, each of which may constitute a separate field. Materials are sometimes classified by the type of bonding present between the atoms:

1. Ionic crystals
2. Covalent crystals
3. Metals
4. Intermetallics
5. Semiconductors
6. Polymers
7. Composite materials
8. Vitreous materials

Sub-fields of materials science

• Nanotechnology --- rigorously, the study of materials where the effects of quantum confinement, the Gibbs-Thomson effect, or any other effect only present at the nanoscale is the defining property of the material; but more commonly, it is the creation and study of materials whose defining structural properties are anywhere from less than a nanometer to one hundred nanometers in scale, such as molecularly engineered materials.
• Crystallography --- the study of how atoms in a solid fill space, the defects associated with crystal structures such as grain boundaries and dislocations, and the characterization of these structures and their relation to physical properties.
• Materials Characterization --- such as diffraction with x-rays, electrons, or neutrons, and various forms of spectroscopy and chemical analysis such as Raman spectroscopy, energy-dispersive spectroscopy (EDS), chromatography, thermogravimetric analysis, electron microscope analysis, etc., in order to understand and define the properties of materials. See also List of surface analysis methods
• Metallurgy --- the study of metals and their alloys, including their extraction, microstructure and processing.
• Biomaterials --- materials that can be used in the human body.
• Electronic and magnetic materials --- materials such as semiconductors used to create integrated circuits, storage media, sensors, and other devices.
• Tribology --- the study of the wear of materials due to friction and other factors.
• Surface science --- interactions and structures between solid-gas solid-liquid or solid-solid interfaces.
• Ceramics and refractories --- high temperature materials including structural ceramics such as RCC, polycrystalline silicon carbide and transformation toughened ceramics

Some practitioners often consider rheology a sub-field of materials science, because it can cover any material that flows. However, modern rheology typically deals with non-Newtonian fluid dynamics, so it is often considered a sub-field of continuum mechanics. See also granular material.

• Glass Science --- any non-crystalline material including inorganic glasses, vitreous metals and non-oxide glasses.

Topics that form the basis of materials science

• Thermodynamics, statistical mechanics, kinetics and physical chemistry, for phase stability, transformations (physical and chemical) and diagrams.
• Crystallography and chemical bonding, for understanding how atoms in a material are arranged.
• Mechanics, to understand the mechanical properties of materials and their structural applications.
• Solid-state physics and quantum mechanics, for the understanding of the electronic, thermal, magnetic, chemical, structural and optical properties of materials.
• Diffraction and wave mechanics, for the characterization of materials.
• Chemistry and polymer science, for the understanding of plastics, colloids, ceramics, liquid crystals, solid state chemistry, and polymers.
• Biology, for the integration of materials into biological systems.
• Continuum mechanics and statistics, for the study of fluid flows and ensemble systems.
• Mechanics of materials, for the study of the relation between the mechanical behavior of materials and their microstructures.

A short list of non-academic materials facilities

• Government labs
  • Argonne National Laboratory
  • Lawrence Berkeley National Laboratory
  • Lawrence Livermore National Laboratory
  • Los Alamos National Laboratory
  • Max Planck Institute
  • Oak Ridge National Laboratory
• Corporate facilities
  • DuPont
  • GE Global Research
  • IBM Thomas J. Watson Research Center

Journals

• Acta Materialia
• JOM
• Advanced Materials
• Computational materials science
• Advanced Functional Materials
• Journal of Materials Chemistry
• Journal of Materials Online - Open Access
• Metallurgical and Materials Transactions

Attribution

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