Thermal shock and thermal loading refer to the disfuntion (and perhaps, crack) of a material due to the heating, especially non-stationary and non-uniform.

Thermal shock in mechanical models

Thermal shock is the name given to cracking as a result of rapid temperature change. Glass and ceramic objects are particularly vulnerable to this form of failure, due to their low toughness, low thermal conductivity, and high thermal expansion coefficients. However, they are used in many high temperature applications due to their high-melting point . In engineering, buckling is a failure mode characterised by a sudden failure of a structural member that is subjected to high compressive stresses where the actual compressive stresses at failure are smaller than the ultimate compressive stresses that the material is capable of withstanding. ... Corrosion is deterioration of essential properties in a material due to reactions with its surroundings. ... Block quote In materials science, creep is the term used to describe the tendency of a material to move or to deform permanently to relieve stresses. ... In materials science, fatigue is the progressive, localised, and permanent structural damage that occurs when a material is subjected to cyclic or fluctuating strains at nominal stresses that have maximum values less than (often much less than) the static yield strength of the material. ... For fractures in geologic formations, see Rock fracture. ... In physics, melting is the process of heating a solid substance to a point (called the melting point) where it turns into a liquid. ... In materials science, wear is the erosion of material from a solid surface by the action of another solid. ... Glass can be made transparent and flat, or into other shapes and colors as shown in this sphere from the Verrerie of Brehat in Brittany. ... Fixed Partial Denture, or Bridge The word ceramic is derived from the Greek word κεραμικός (keramikos). ... Structural failure refers to loss of the load-carying capacity of a component or member within the structure or of the structure itself. ... In materials science and metallurgy, toughness is the resistance to fracture of a material when stressed. ... In physics, thermal conductivity, k, is the intensive property of a material that indicates its ability to conduct heat. ... The melting point of a crystalline solid is the temperature at which it changes state from solid to liquid. ...

Thermal shock occurs when a thermal gradient causes different parts of an object to expand by different amounts. This differential expansion can be understood in terms of stress or of strain, equivalently. At some point, this stress overcomes the strength of the material, causing a crack to form. If nothing stops this crack from propagating through the material, it will cause the object's structure to fail. For other uses, see Gradient (disambiguation). ... During heat transfer, the energy that is stored in the intermolecular bonds between atoms changes. ... Stress is the internal distribution of force per unit area that balances and reacts to external loads applied to a body. ... This article is about the deformation of materials. ... Tensile strength measures the force required to pull something such as rope, wire, or a structural beam to the point where it breaks. ...

Thermal shock can be prevented by:

1. Reducing the thermal gradient seen by the object, by
   1. changing its temperature more slowly
   2. increasing the material's thermal conductivity
2. Reducing the material's coefficient of thermal expansion
3. Increasing its strength
4. Increasing its toughness, by
   1. crack tip blunting, i.e., plasticity or phase transformation
   2. crack deflection

Borosilicate glass such as Pyrex is made to withstand thermal shock better than most other glass through a combination of reduced expansion coefficient and greater strength, though fused quartz outperforms it in both these respects. Some glass-ceramic materials include a controlled proportion of material with a negative expansion coefficient, so that the overall coefficient can be reduced to almost exactly zero over a reasonably wide range of temperatures. In physics, thermal conductivity, k, is the intensive property of a material that indicates its ability to conduct heat. ... During heat transfer, the energy that is stored in the intermolecular bonds between atoms changes. ... Tensile strength measures the force required to pull something such as rope, wire, or a structural beam to the point where it breaks. ... In materials science and metallurgy, toughness is the resistance to fracture of a material when stressed. ... Look up plasticity in Wiktionary, the free dictionary. ... Zirconia (ZrO2) is a white crystalline oxide of zirconium. ... It has been suggested that Kimax be merged into this article or section. ... Pyrex is a brand name of borosilicate glass introduced by Corning Glass Works in 1915. ... Glass-ceramic is a mixture of glass and ceramic materials (mainly lithium-, silicon-, or aluminium-oxides) yielding a material that is impervious to even extreme temperature shocks. ...

Reinforced carbon-carbon is extremely resistant to thermal shock, due to graphite's extremely high thermal conductivity and low expansion coefficient, the high strength of carbon fiber, and a reasonable ability to deflect cracks within the structure. Mock-up of a space shuttle leading edge, showing brittle failure of RCC due to foam impact reproducing the conditions of Columbias final launch. ... Graphite (named by Abraham Gottlob Werner in 1789, from the Greek γραφειν: to draw/write, for its use in pencils) is one of the allotropes of carbon. ... Carbon fiber composite is a strong, light and very expensive material. ...

Thermal shock parameter in the physics of solid-state lasers

The laser gain medium generates heat. This heat is drained through the heat sink. The transfer of heat occurs at certain temperature gradient. The non-uniform thermal expansion of a bulk material causes the stress and tension, which may break the device even at slow change of the temperature. (for example, continuous-wave operation. This phenomenon is also called thermal shock. The robustness of a laser material to the thermal shock is characterized with the thermal shock parameter ^[1] Physics (Greek: (phúsis), nature and (phusiké), knowledge of nature) is the science concerned with the fundamental laws of the universe. ... A solid-state laser is a laser that uses a gain medium that is a solid, rather than a liquid such as dye lasers or a gas such as gas lasers. ... A laser (acronym for Light Amplification by Stimulated Emission of Radiation) is an optical source that emits light in a coherent beam. ... A laser system generally consists of three important parts: An energy source (usually referred to as the pump or pump source); A gain medium or laser medium; A mirror, or system of mirrors, forming an optical resonator. ... It has been suggested that this article or section be merged into Thermal management of electronic devices and systems. ... The temperature gradient in a given direction from a given spatial starting point is the rate at which temperature changes relative to distance in that direction from that point. ... In physics, thermal expansion is the tendency of matter to increase in volume or pressure when heated. ... Stress has different meanings in different fields: Look up stress in Wiktionary, the free dictionary. ... Tension may mean: In physics, tension is a force related to the stretching of a string or a similar object. ... A continuous wave or continuous waveform (CW) is an electromagnetic wave of constant amplitude and frequency; and in mathematical analysis, of infinite duration. ...

 , 

where
is thermal conductivity,
is maximal tension the material can resist,
is the Young's modulus, and
is the Poisson ratio.
In physics, thermal conductivity, k, is the intensive property of a material that indicates its ability to conduct heat. ... Tension may mean: In physics, tension is a force related to the stretching of a string or a similar object. ... This article does not adequately cite its references or sources. ... When a sample of material is stretched in one direction, it tends to get thinner in the other two directions. ...

Roughly, at the efficient operation of laser, the power of heat henerated in the gain medium is proportional to the output power of the laser, and the coefficient of proportionality can be interpreted as heat generation parameter; then, The heat generation parameter is always greater than the quantum defect of the laser action , where and are frequency of the pump and that of the lasing. A laser system generally consists of three important parts: An energy source (usually referred to as the pump or pump source); A gain medium or laser medium; A mirror, or system of mirrors, forming an optical resonator. ... The term quantum defect can refer to two things: The quantum defect of a laser is the energy lost (not turned into photons at the lasing wavelength) when electrons in the gain medium transition from an excited to a non-excited state. ...

Then, for the layer of the gain medium placed at the heat sink, the maximal power can be estimated as A laser system generally consists of three important parts: An energy source (usually referred to as the pump or pump source); A gain medium or laser medium; A mirror, or system of mirrors, forming an optical resonator. ... It has been suggested that this article or section be merged into Thermal management of electronic devices and systems. ...

 , 

where is thiclness of the layer and is the transversal size. This estimate assumes the unilateral heat drain, as it takes place in the active mirrors. For the double-side sink, the coefficient 4 should be applied. Fig. ...

Thermal loading

The estimate above is not the only parameter which determines the limit of overheating of a gain medium. The maximal raise of temperature, at which the medium still can efficiently lase, is also important propertiy of the laser material. This overheating limits the maximal power with estimate A laser system generally consists of three important parts: An energy source (usually referred to as the pump or pump source); A gain medium or laser medium; A mirror, or system of mirrors, forming an optical resonator. ...

Combination of the two estimates above of the maximal power gives the estimate

where

is thermal loading; parameter, which is important property of the laser material. The Thermal loading, saturation intensity and the round-trip loss determine the limit of power scaling of the disk lasers ^[2]. Roughly, the maximal power at the optimised sizes and , is of order of . This estimate is very sensitive to the loss . However, the same expression can be interpreted as a robust estimate of the upper pound of the loss required for the desirable output power : Round-trip gain refers to the laser physics, and laser cavitys (or laser resonators). ... Power scaling of a laser is increasing its output power without changing the geometry, shape, or principle of operation. ... // An optically-pumped disk laser A disk laser is a type of solid-state laser characterized by a heat drain and laser output that are realized on opposite sides of a thin layer of active medium. ...

All the disk lasers reported seem to work at the round-trip loss below this estimate. The thermal shock parameter and the loading repend of the temperature of the heat sink. Certan hopes are relates with a laser, operating at cryogenic temperatures. The corresponding Increase of the thermal shock parameter would allow to softer requirements for the round-trip loss of the disk laser at the power scaling. // An optically-pumped disk laser A disk laser is a type of solid-state laser characterized by a heat drain and laser output that are realized on opposite sides of a thin layer of active medium. ... Round-trip gain refers to the laser physics, and laser cavitys (or laser resonators). ... // An optically-pumped disk laser A disk laser is a type of solid-state laser characterized by a heat drain and laser output that are realized on opposite sides of a thin layer of active medium. ... Power scaling of a laser is increasing its output power without changing the geometry, shape, or principle of operation. ...

Examples of Thermal Shock Failure

• In the sci-fi movie Alien 3, the alien is able to survive being immersed in molten lead, but when the sprinklers are activated, the cool water hitting the super hot alien exoskeleton causes it to crack and the alien dies.

• A Sheepherder stove is basically a steel box on legs, that has a cast iron top. One builds a wood fire inside the box and cooks on the top outer surface of the box, like a griddle. If one builds too hot a fire, and then tries to cool the stove by pouring water on the top surface, it will crack and perhaps fail by thermal shock.

• Ice cubes placed in a glass of warm water crack by thermal shock as the exterior surface increases in temperature much faster than the interior surfaces. Because of thermal expansion, the outer surface stretches because it is hotter, but the inner surface is nearly the same length, and thus, the crack forms to allow for this difference.

Alien³ is a science fiction/horror movie that opened May 22, 1992. ...

See also

• overheating
• stress or strain
• toughness
• temperature gradient
• thermal conductivity
• disk laser
• gain medium
• quantum defect

Stress has different meanings in different fields: Look up stress in Wiktionary, the free dictionary. ... Look up strain in Wiktionary, the free dictionary. ... In materials science and metallurgy, toughness is the resistance to fracture of a material when stressed. ... The temperature gradient in a given direction from a given spatial starting point is the rate at which temperature changes relative to distance in that direction from that point. ... In physics, thermal conductivity, k, is the intensive property of a material that indicates its ability to conduct heat. ... // An optically-pumped disk laser A disk laser is a type of solid-state laser characterized by a heat drain and laser output that are realized on opposite sides of a thin layer of active medium. ... A laser system generally consists of three important parts: An energy source (usually referred to as the pump or pump source); A gain medium or laser medium; A mirror, or system of mirrors, forming an optical resonator. ... The term quantum defect can refer to two things: The quantum defect of a laser is the energy lost (not turned into photons at the lasing wavelength) when electrons in the gain medium transition from an excited to a non-excited state. ...

References

1. ^ W.F.Krupke; M.D.Shinn, J.E.Marion, J.A.Caird, and S.E.Stokowski (1986). "Spectroscopic, optical, and thermomechanical properties of neodymium- and chromium-doped gadolinium scandium gallium garnet". JOSAB 3 (1): 102-114.
2. ^ D. Kouznetsov; J.F. Bisson, J. Dong, and K. Ueda (2006). "Surface loss limit of the power scaling of a thin-disk laser". JOSAB 23 (6): 1074–1082. Retrieved on 2007-01-26. ; [1]