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Brittle
 
 
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A material
Material

Materials are substances or components with certain physical properties which are used as inputs to Production, costs, and pricing or manufacturing....
 is brittle if it is liable to fracture
Fracture

A fracture is the separation of an object or material into two, or more, pieces under the action of stress .The word fracture is often applied to bones of living creatures, or to crystals or crystalline materials, such as gemstones or metal....
 when subjected to stress
Stress (physics)

In continuum mechanics, stress is a measure of the average amount of force exerted per unit area. It is a measure of the intensity of the total internal forces acting within a body across imaginary internal surfaces, as a reaction to external applied forces and body forces....
. That is, it has little tendency to deform (or strain
Strain (materials science)

In continuum mechanics, the infinitesimal strain theory, sometimes called small deformation theory, small displacement theory, or small displacement-gradient theory, deals with infinitesimal Deformation s of a Continuum mechanics....
) before fracture. This fracture absorbs relatively little energy
Energy

In physics, energy is a scalar physical quantity that describes the amount of Work_ that can be performed by a force. Energy is an attribute of objects and systems that is subject to a conservation law....
, even in materials of high strength
Strength of materials

In materials science, the strength of a material refers to the material's ability to withstand an applied stress without failure. Yield strength refers to the point on the engineering stress-strain curve beyond which the material begins deformation that cannot be reversed upon removal of the loading....
, and usually makes a snapping sound.

When used in materials science
Materials science

Materials science or materials engineering is an interdisciplinary field involving the properties of matter and its applications to various areas of science and engineering....
, it is generally applied to materials that fail in tension
Tension (mechanics)

In physics, tension is the magnitude of the pulling force exerted by a string, cable, chain, or similar object on another object. Tension is measured newtons or pounds-force and is always parallel to the string on which it applies....
 rather than shear
Shear stress

File:Shear stress.JPGA shear stress, denoted , is defined as a stress which is applied parallel or tangent to a face of a material, as opposed to a normal stress which is applied perpendicularly....
, or when there is little or no evidence of plastic deformation
Plasticity (physics)

In physics and materials science, plasticity describes the deformation of a material undergoing non-reversible changes of shape in response to applied forces....
 before failure.

When a material has reached the limit of its strength, it usually has the option of either deformation or fracture.






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A material
Material

Materials are substances or components with certain physical properties which are used as inputs to Production, costs, and pricing or manufacturing....
 is brittle if it is liable to fracture
Fracture

A fracture is the separation of an object or material into two, or more, pieces under the action of stress .The word fracture is often applied to bones of living creatures, or to crystals or crystalline materials, such as gemstones or metal....
 when subjected to stress
Stress (physics)

In continuum mechanics, stress is a measure of the average amount of force exerted per unit area. It is a measure of the intensity of the total internal forces acting within a body across imaginary internal surfaces, as a reaction to external applied forces and body forces....
. That is, it has little tendency to deform (or strain
Strain (materials science)

In continuum mechanics, the infinitesimal strain theory, sometimes called small deformation theory, small displacement theory, or small displacement-gradient theory, deals with infinitesimal Deformation s of a Continuum mechanics....
) before fracture. This fracture absorbs relatively little energy
Energy

In physics, energy is a scalar physical quantity that describes the amount of Work_ that can be performed by a force. Energy is an attribute of objects and systems that is subject to a conservation law....
, even in materials of high strength
Strength of materials

In materials science, the strength of a material refers to the material's ability to withstand an applied stress without failure. Yield strength refers to the point on the engineering stress-strain curve beyond which the material begins deformation that cannot be reversed upon removal of the loading....
, and usually makes a snapping sound.

When used in materials science
Materials science

Materials science or materials engineering is an interdisciplinary field involving the properties of matter and its applications to various areas of science and engineering....
, it is generally applied to materials that fail in tension
Tension (mechanics)

In physics, tension is the magnitude of the pulling force exerted by a string, cable, chain, or similar object on another object. Tension is measured newtons or pounds-force and is always parallel to the string on which it applies....
 rather than shear
Shear stress

File:Shear stress.JPGA shear stress, denoted , is defined as a stress which is applied parallel or tangent to a face of a material, as opposed to a normal stress which is applied perpendicularly....
, or when there is little or no evidence of plastic deformation
Plasticity (physics)

In physics and materials science, plasticity describes the deformation of a material undergoing non-reversible changes of shape in response to applied forces....
 before failure.

When a material has reached the limit of its strength, it usually has the option of either deformation or fracture. A naturally malleable metal can be made stronger by impeding the mechanisms of plastic deformation (reducing grain
Crystallite

A crystallite is a domain of solid-state matter that has the same structure as a single crystal. Metallurgy often refer to crystallites as "grains"....
 size, dispersion strengthening, work hardening
Work hardening

Work hardening, strain hardening, or cold work is the strength of materials by, macroscopically speaking, plastic deformation . As the material becomes increasingly saturated with new dislocations, more dislocations are prevented from nucleating ....
, etc.), but if this is taken to an extreme, fracture becomes the more likely outcome, and the material can become brittle. Improving material toughness
Toughness

Toughness, in materials science and metallurgy, is the resistance to fracture of a material when stress . It is defined as the amount of energy per volume that a material can absorb before rupture ....
 is therefore a balancing act.

Toughening


This principle generalizes to other classes of material. Naturally brittle materials, such as glass
Glass

Glass generally refers to a Hardness, brittle, transparency amorphous solid, such as that used for windows, many Glass Bottles, or eyewear, including, but not limited to, soda-lime glass, borosilicate glass, acrylic glass, sugar glass, Muscovite , or aluminium oxynitride....
, are not difficult to toughen effectively. Most such techniques involve one of two mechanisms: to deflect or absorb the tip of a propagating crack, or to create carefully-controlled residual stresses
Stress (physics)

In continuum mechanics, stress is a measure of the average amount of force exerted per unit area. It is a measure of the intensity of the total internal forces acting within a body across imaginary internal surfaces, as a reaction to external applied forces and body forces....
 so that cracks from certain predictable sources will be forced closed. The first principle is used in laminated glass
Laminated glass

Laminated glass is a type of safety glass that holds together when wikt:shattered. In the event of breaking, it is held in place by an interlayer, typically of polyvinyl butyral , between its two or more layers of glass....
 where two sheets of glass are separated by an interlayer of polyvinyl butyral
Polyvinyl butyral

Polyvinyl butyral is a resin usually used for applications that require strong binding, optical clarity, adhesion to many surfaces, toughness and flexibility....
, which as a viscoelastic polymer absorbs the growing crack. The second method is used in toughened glass
Toughened glass

Toughened or tempered glass is glass that has been processed by controlled heat treatment or chemical treatments to increase its strength compared with normal glass....
 and pre-stressed concrete. A demonstration of glass toughening is provided by Prince Rupert's Drop
Prince Rupert's Drop

File:Prince Ruperts drops.jpgPrince Rupert's Drops are a glass curiosity created by dripping hot molten glass into cold water. The glass cools into a tadpole-shaped Drop with a long, thin, tail....
. Brittle polymers can be toughened by using rubber particles to initiate crazes when a sample is stressed, a good example being high impact polystyrene or HIPS. The least-brittle structural ceramics are silicon carbide
Silicon carbide

Silicon carbide is a Chemical compound of silicon and carbon bonded together to form ceramics, but it also occurs in nature as the extremely rare mineral moissanite....
 (mainly by virtue of its high strength) and transformation-toughened zirconia.

Effect of pressure


Generally, the brittle strength of a material can be increased by pressure
Pressure

Pressure is the force per unit area applied to an object in a direction surface normal to the surface. Gauge pressure is the pressure relative to the local atmospheric or ambient pressure....
. This happens as an example in the brittle-ductile transition zone
Brittle-ductile transition zone

The brittle-ductile transition zone is the strongest part of the Crust . For quartz and feldspar rich rocks in continental crust this occurs at an approximate depth of 13-18 km ....
 at an approximate depth of 10 km in the Earth's crust
Crust (geology)

In geology, a crust is the outermost solid shell of a planet or moon, which is chemically distinct from the underlying mantle . Crusts of Earth , our Moon, Mercury , Venus, and Mars have been generated largely by igneous processes, and these crusts are richer in incompatible elements than their respective mantle s....
, at which rock becomes less likely to fracture, and more likely to deform ductilely
Ductility

Ductility is a mechanical property used to describe the extent to which materials can be deformed deformation without fracture.In material science, ductility specifically refers to a material's ability to deform under tensile stress; this is often characterized by the material's ability to be stretched into a wire....
.

Crack growth


Supersonic fracture
Supersonic fracture

Supersonic fractures are fractures where the fracture velocity moves faster than the speed of sound in the material. This phenomenon was first discovered by scientists from the Max Planck Institute for Metals Research in Stuttgart and IBM Almaden Research Center in San Jose, California ....
 is crack motion faster than the speed of sound in a brittle material. This phenomenon was first discovered by scientists from the Max Planck Institute for Metals Research
Max Planck Institute for Metals Research

The Max Planck Institute for Metals Research is a research institute of the Max Planck Society located in Stuttgart. The institute was founded 1921 as Kaiser Wilhelm Institute for Metal Research in Berlin and closed 1932....
 in Stuttgart
Stuttgart

Stuttgart is the capital of the state of Baden-W?rttemberg in southern Germany. The list of cities in Germany, Stuttgart has a population of 590,429 while the metropolitan area referred to as Stuttgart Region has a population of 2.7 million ....
 (Markus J. Buehler
Markus J. Buehler

Markus J. Buehler is a German-American materials science working in the area of computational multi-scale modeling of deformation and fracture of materials....
 and Huajian Gao
Huajian Gao

Huajian Gao is an united states materials scientist and engineer. He joined the Max Planck Society in 2001 and is currently Director of the Max Planck Institute for Metals Research, Stuttgart....
) and IBM Almaden Research Center in San Jose
San Jose, California

San Jose or San Jos? is the List of cities in California city in California and the List of United States cities by population in the United States....
, California (Farid F. Abraham
Farid F. Abraham

Farid F. Abraham is an United States scientist.Abraham earned his Bachelor of Science and Doctor of Philosophy from the University of Arizona in 1959 and 1962, respectively....
).

See also

  • Izod impact strength test
    Izod impact strength test

    Izod impact strength testing is an ASTM standard method of determining impact strength. A notched sample is generally used to determine impact strength....
  • Charpy impact test
    Charpy impact test

    The Charpy impact test, also known as the Charpy v-notch test, is a Wiktionary:standardized high strain -rate test which determines the amount of energy absorbed by a material during fracture....
  • Fractography
    Fractography

    Fractography is the study of fracture surfaces of materials. Fractographic methods are routinely used to determine the cause of failure in engineering structures, especially in product failure and the practice of forensic engineering or failure analysis....
  • Fracture
    Fracture

    A fracture is the separation of an object or material into two, or more, pieces under the action of stress .The word fracture is often applied to bones of living creatures, or to crystals or crystalline materials, such as gemstones or metal....
  • Forensic engineering
    Forensic engineering

    Forensics engineering is the investigation of material science, product , structures or components that fail or do not operate/function as intended, causing personal injury or damage to property....


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