Embrittlement
Encyclopedia
Embrittlement is a loss of ductility
of a material, making it brittle
. Various materials have different mechanisms of embrittlement.
s become brittle, which is known as the embrittlement temperature.
Ductility
In materials science, ductility is a solid material's ability to deform under tensile stress; this is often characterized by the material's ability to be stretched into a wire. Malleability, a similar property, is a material's ability to deform under compressive stress; this is often characterized...
of a material, making it brittle
Brittle
A material is brittle if, when subjected to stress, it breaks without significant deformation . Brittle materials absorb relatively little energy prior to fracture, even those of high strength. Breaking is often accompanied by a snapping sound. Brittle materials include most ceramics and glasses ...
. Various materials have different mechanisms of embrittlement.
- Hydrogen embrittlementHydrogen embrittlementHydrogen embrittlement is the process by which various metals, most importantly high-strength steel, become brittle and fracture following exposure to hydrogen...
is the effect of hydrogenHydrogenHydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
absorption on some metals and alloys.
- Sulfide stress cracking is the embrittlement caused by absorption of hydrogen sulfideHydrogen sulfideHydrogen sulfide is the chemical compound with the formula . It is a colorless, very poisonous, flammable gas with the characteristic foul odor of expired eggs perceptible at concentrations as low as 0.00047 parts per million...
.
- Liquid metal embrittlementLiquid metal embrittlementLiquid metal embrittlement is a phenomenon of practical importance, where certain ductile metals experience drastic loss in tensile ductility or undergo brittle fracture when tested in the presence of specific liquid metals. Generally, a tensile stress, either externally applied or internally...
(LME) is the embrittlement caused by liquid metals.
- Metal-induced embrittlement (MIE) is the embrittlement caused by diffusion of atoms of metal, either solid or liquid, into the material.
- Neutron radiationNeutron radiationNeutron radiation is a kind of ionizing radiation which consists of free neutrons. A result of nuclear fission or nuclear fusion, it consists of the release of free neutrons from atoms, and these free neutrons react with nuclei of other atoms to form new isotopes, which, in turn, may produce...
causes embrittlement of some materials, neutron-induced swellingNeutron-induced swellingNeutron-induced swelling is the increase of volume and decrease of density of materials subjected to intense neutron radiation. Neutrons impacting the material's lattice rearrange its atoms, causing buildup of dislocations, voids, and Wigner energy...
, and buildup of Wigner energy. This is a process especially important for neutron moderatorNeutron moderatorIn nuclear engineering, a neutron moderator is a medium that reduces the speed of fast neutrons, thereby turning them into thermal neutrons capable of sustaining a nuclear chain reaction involving uranium-235....
s and nuclear reactor vesselReactor vesselIn a nuclear power plant, the reactor vessel is a pressure vessel containing the Nuclear reactor coolant and reactor core.Not all power reactors have a reactor vessel. Power reactors are generally classified by the type of coolant rather than by the configuration of the reactor vessel used to...
s (see ductilityDuctilityIn materials science, ductility is a solid material's ability to deform under tensile stress; this is often characterized by the material's ability to be stretched into a wire. Malleability, a similar property, is a material's ability to deform under compressive stress; this is often characterized...
).
- The primary embrittlement mechanism of plastics is gradual loss of plasticizerPlasticizerPlasticizers or dispersants are additives that increase the plasticity or fluidity of the material to which they are added; these include plastics, cement, concrete, wallboard, and clay. Although the same compounds are often used for both plastics and concretes the desired effects and results are...
s, usually by overheating or aging.
- The primary embrittlement mechanism of asphaltAsphaltAsphalt or , also known as bitumen, is a sticky, black and highly viscous liquid or semi-solid that is present in most crude petroleums and in some natural deposits, it is a substance classed as a pitch...
is by oxidation, which is most severe in warmer climates. Asphalt pavement embrittlement can lead to various forms of cracking patterns, including longitudinal, transverse, and block (hexagonal). Asphalt oxidation is related to polymer degradationPolymer degradationPolymer degradation is a change in the properties—tensile strength, colour, shape, etc.—of a polymer or polymer-based product under the influence of one or more environmental factors such as heat, light or chemicals such as acids, alkalis and some salts...
, as these materials bear similarities in their chemical composition.
Cryogenic embrittlement
Around cryogenic temperatures plastics and rubberRubber
Natural rubber, also called India rubber or caoutchouc, is an elastomer that was originally derived from latex, a milky colloid produced by some plants. The plants would be ‘tapped’, that is, an incision made into the bark of the tree and the sticky, milk colored latex sap collected and refined...
s become brittle, which is known as the embrittlement temperature.
| Material | Temperature [°F] | Temperature [°C] |
|---|---|---|
| Plastics | ||
| ABS ABS - Anatomy :* Abdominal muscles , which is the rectus abdominis or the stomach muscles-Music and media:Music ensembles* A.B.'s, a Japanese 80's instrumental band* Abingdon Boys School, a Japanese rock band... |
-270 F | |
| Acteal Acteal Acteal is a small village in the municipality of Chenalhó, in the Mexican state of Chiapas, about 20 km north of San Cristóbal de las Casas. It became known internationally at the end of 1997 for the massacre of 45 indigenous people.... |
-300 F | |
| Delrin | -275 to -300 | -171 to -184 |
| Nylon Nylon Nylon is a generic designation for a family of synthetic polymers known generically as polyamides, first produced on February 28, 1935, by Wallace Carothers at DuPont's research facility at the DuPont Experimental Station... |
-275 to -300 | -171 to -184 |
| Polytron | -300 F | |
| Polypropylene Polypropylene Polypropylene , also known as polypropene, is a thermoplastic polymer used in a wide variety of applications including packaging, textiles , stationery, plastic parts and reusable containers of various types, laboratory equipment, loudspeakers, automotive components, and polymer banknotes... |
-300 to -310 | -184 to -190 |
| Teflon | -275 F | |
| Rubbers | ||
| Buna-N | -225 F | |
| EPDM | -275 to -300 | -171 to -184 |
| Ethylene propylene | -275 to -300 | -171 to -184 |
| Hycar | -210 to -275 | -134 to -171 |
| Natural rubber | -225 to -275 | -143 to -171 |
| Neoprene Neoprene Neoprene or polychloroprene is a family of synthetic rubbers that are produced by polymerization of chloroprene. Neoprene in general has good chemical stability, and maintains flexibility over a wide temperature range... |
-225 to -300 | -143 to -184 |
| Nitrile Nitrile A nitrile is any organic compound that has a -C≡N functional group. The prefix cyano- is used interchangeably with the term nitrile in industrial literature. Nitriles are found in many useful compounds, one example being super glue .Inorganic compounds containing the -C≡N group are not called... |
-275 to -310 | -171 to -190 |
| Nitrile-butadiene | -250 to -270 | -157 to -168 |
| Silicone Silicone Silicones are inert, synthetic compounds with a variety of forms and uses. Typically heat-resistant and rubber-like, they are used in sealants, adhesives, lubricants, medical applications , cookware, and insulation.... |
-300 F | |
| Urethane Polyurethane A polyurethane is any polymer composed of a chain of organic units joined by carbamate links. Polyurethane polymers are formed through step-growth polymerization, by reacting a monomer with another monomer in the presence of a catalyst.Polyurethanes are... |
-275 to -300 | -171 to -184 |
| Viton Viton Viton is a brand of synthetic rubber and fluoropolymer elastomer commonly used in O-rings and other molded or extruded goods. The name is a registered trademark of DuPont Performance Elastomers L.L.C..... |
-275 to -300 | -171 to -184 |
| Metals | ||
| Zinc Zinc Zinc , or spelter , is a metallic chemical element; it has the symbol Zn and atomic number 30. It is the first element in group 12 of the periodic table. Zinc is, in some respects, chemically similar to magnesium, because its ion is of similar size and its only common oxidation state is +2... |
-200 F | |