Materials science is the multidisciplinary field relating the performance and function of matter in any and all applications to its micro, nano, and atomic-structure, and vice versa. It is closely related to applied physics, chemical engineering and chemistry, biology, mechanical engineering, and electrical engineering; it is indeed one of the most multidisciplinary science and engineering fields. Fundamentally, all of nanoscience and nanotechnology is materials science. Because of this, in recent years materials science has been propelled to the forefront at many universities, sometimes controversially: many academics feel that the 'nano' buzzword is bringing in large amounts of funding at the cost of detracting from the teaching of fundamental materials science by putting too much emphasis on devices and applications which may or may not see fruition as working products.
History is often defined by the materials used by advanced civilizations of an era; the stone age, bronze age, and steel age are examples. Materials science in a primitive form is thus one of the oldest forms of engineering and applied science. A true understanding of materials, however, was not possible until the realization by Willard Gibbs in the second half of the 19th century of the thermodynamic properties which relate how atoms are arranged in various phases (whether they are various types of solids, liquids, or gases) to the properties of the material. Since then, materials science has been the area of research where rather than looking for and discovering materials and exploiting their properties--which was the unscientific method used for centuries--we instead aim to understand materials fundamentally so that we can invent and create ones with the properties we desire. Modern materials science in the form we know it today is 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. Until the 1960's (and in some cases until decades afterwards ), many university departments which are now materials science departments were metallurgy departments. Since then the field has broadened to include every class of materials. Besides space exploration, materials science has enabled revolutionary technologies such as plastics, semiconductors, and biomaterials.
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 way in which the material was processed (formed or created) being the main determinant of the structure and thus properties. Say we want to create a high-performance metal that is harder, stronger, and tougher than any other metal we have. We will first test and measure (characterize) a variety of existing metals to compare their properties and understand their structure. Structurally we would like to know how atoms pack on the finest scale to how clumps of atoms and impurities organize themselves, as well as the defects that are present. We will relate the structure to how the material was processed, and draw conclusions as to what processing conditions we may use to create the desired properties in our new high-performance metal. After creating it, we will characterize it and see what happened, hopefully learning what went wrong and what went right. Although such a case is broadly oversimplified and straightforward, the collective field of materials science is in effect carrying this process out for a multitude of material types, properties, and applications.
An old adage in materials science says: "materials are like people; it is the defects that make them interesting." Indeed, a perfect crystal of a material like Aluminum is largely uninteresting and useless; but, introduce the right impurities into the aluminum as precipitates in the correct quantity, and you will have a high strength alloy that is used in the manufacture of most bicycles, automobiles, etc. Similarly, it is the impurities which give minerals and glass their color; it is the imperfections (as dislocations) in the crystal structure of steel which gives it its strength; and it is the impurities we introduce into Silicon which give us the ability to use it to form microchips.
The widespread applications of materials science give rise to the title materials science and engineering. 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/or to troubleshoot. 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.).
One kind of material science is "materials physics," which is a field of physics 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:
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.
- 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, etc., in order to understand and define the properties of materials.
- Metallurgy --- the study of metals, their alloys, and the microstructure and processing of them.
- Biomaterials --- materials that can be used in the human body.
- Functional materials: Semiconductors, electronic materials, and magnetic materials --- materials used to create integrated circuits, storage media, sensors, and other electronic devices.
- Tribology --- the study of the wear of materials due to friction and other factors.
Note that 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 consider a sub-field of Continuum mechanics. See also granular material.
- Surface science --- interactions and structures between solid-gas solid-liquid or solid-solid interfaces.
- Ceramics, which can be subdivided into:
Topics that form the basis of materials science
- Thermodynamics, statistical mechanics, and kinetics, for phase stability, transformations 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, and optical properties of materials.
- Diffraction and wave mechanics, for the characterization of materials.
- Chemistry and polymer science, for the understanding of plastics and polymers.
- Biology, for the integration of materials into biological systems.
- Continuum mechanics and statistics, for the study of fluid flows and ensemble systems.
A non-exhaustive list of some top materials science research institutes and facilities, in no particular order
- University of California, Berkeley
- Lawrence Berkeley National Laboratory
- Lawrence Livermore National Laboratory
- IBM Thomas J. Watson Research Center
- Northwestern University
- Carnegie Mellon
- Case Western Reserve
- University of Illinois at Urbana-Champaign
- Georgia Tech
- University of Wisconsin, Madison
- University of Pennsylvania
- University of California, Santa Barbara
- University of California, Davis
- Max Planck Institute
- Los Alamos National Laboratory
- Cambridge University
- Federal University of São Carlos (UFSCar)
- Timeline of materials technology
- Bio-based materials
- Liquid crystal
- Important publications in materials science
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