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Embrittlement
Embrittlement is a significant decrease of ductility of a material, which makes the material Brittleness, brittle. Embrittlement is used to describe any phenomena where the environment compromises a stressed material's mechanical performance, such as temperature or environmental composition. This is oftentimes undesirable as brittle fracture occurs quicker and can much more easily propagate than ductile fracture, leading to complete failure of the equipment. Various materials have different mechanisms of embrittlement, therefore it can manifest in a variety of ways, from slow crack growth to a reduction of tensile ductility and toughness. Mechanisms Embrittlement is a series complex mechanism that is not completely understood. The mechanisms can be driven by temperature, stresses, grain boundaries, or material composition. However, by studying the embrittlement process, preventative measures can be put in place to mitigate the effects. There are several ways to study the mechanis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Liquid Metal Embrittlement
Liquid metal embrittlement (LME), also known as liquid metal induced embrittlement, is a phenomenon of practical importance, where certain ductile metals experience drastic loss in tensile ductility or undergo brittle fracture when exposed to specific liquid metals. Generally, a tensile stress, either externally applied or internally present, is needed to induce embrittlement. Exceptions to this rule have been observed, as in the case of aluminium in the presence of liquid gallium.J. Huntington, ''Inst. Metals'', 11 (1914), 108 This phenomenon has been studied since the beginning of the 20th century. Many of its phenomenological characteristics are known and several mechanisms have been proposed to explain it.B. Joseph, M. Picat, and F. Barbier, ''Eur. Phys. J. AP'', 5 (1999), 19D.G. Kolman, "Environmentally Induced Cracking, Liquid Metal Embrittlement" in "ASM Handbook, Volume 13A, Corrosion: Fundamentals, Testing and Protection", ASM International, Materials Park, OH, pp. 381-392 ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neutron Embrittlement
Neutron embrittlement, sometimes more broadly radiation embrittlement, is the embrittlement of various materials due to the action of neutrons. This is primarily seen in nuclear reactors, where the release of high-energy neutrons causes the long-term degradation of the reactor materials. The embrittlement is caused by the microscopic movement of atoms that are hit by the neutrons; this same action also gives rise to neutron-induced swelling causing materials to grow in size, and the Wigner effect causing energy buildup in certain materials that can lead to sudden releases of energy. Neutron embrittlement mechanisms include: * Hardening and dislocation pinning due to nanometer features created by irradiation * Generation of lattice defects in collision cascades via the high-energy recoil atoms produced in the process of neutron scattering. * Diffusion of major defects, which leads to higher amounts of solute diffusion, as well as formation of nanoscale defect-solute cluster complex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metal-induced Embrittlement
Metal-induced embrittlement (MIE) is the embrittlement caused by diffusion of metal, either solid or liquid, into the base material. Metal induced embrittlement occurs when metals are in contact with low-melting point metals while under tensile stress. The embrittler can be either solid (SMIE) or liquid (liquid metal embrittlement). Under sufficient tensile stress, MIE failure occurs instantaneously at temperatures just above melting point. For temperatures below the melting temperature of the embrittler, solid-state diffusion is the main transport mechanism.P. Gordon, "Metal-Induced embrittlement of metals—an evaluation of embrittler transport mechanisms" Metallurgical Transactions A, 9, p. 267 (1978). https://doi.org/10.1007/BF02646710 This occurs in the following ways: * Diffusion through grain boundaries near the crack of matrix * Diffusion of first monolayer heterogeneous surface embrittler atoms * Second monolayer heterogenous surface diffusion of embrittler * Surface diff ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ductility
Ductility is a mechanical property commonly described as a material's amenability to drawing (e.g. into wire). In materials science, ductility is defined by the degree to which a material can sustain plastic deformation under tensile stress before failure. Ductility is an important consideration in engineering and manufacturing. It defines a material's suitability for certain manufacturing operations (such as cold working) and its capacity to absorb mechanical overload.. Some metals that are generally described as ductile include gold and copper. However, not all metals experience ductile failure as some can be characterized with brittle failure like cast iron. Polymers generally can be viewed as ductile materials as they typically allow for plastic deformation. Malleability, a similar mechanical property, is characterized by a material's ability to deform plastically without failure under compressive stress. Historically, materials were considered malleable if they were am ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ductility
Ductility is a mechanical property commonly described as a material's amenability to drawing (e.g. into wire). In materials science, ductility is defined by the degree to which a material can sustain plastic deformation under tensile stress before failure. Ductility is an important consideration in engineering and manufacturing. It defines a material's suitability for certain manufacturing operations (such as cold working) and its capacity to absorb mechanical overload.. Some metals that are generally described as ductile include gold and copper. However, not all metals experience ductile failure as some can be characterized with brittle failure like cast iron. Polymers generally can be viewed as ductile materials as they typically allow for plastic deformation. Malleability, a similar mechanical property, is characterized by a material's ability to deform plastically without failure under compressive stress. Historically, materials were considered malleable if they were am ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rehbinder Effect
The Rehbinder effect in physics is the reduction in the hardness and ductility of a material, particularly metals, by a surfactant film. A proposed explanation for this effect is the disruption of surface oxide films, and the reduction of surface energy by surfactants. The effect is of particular importance in machining, as lubricants A lubricant (sometimes shortened to lube) is a substance that helps to reduce friction between surfaces in mutual contact, which ultimately reduces the heat generated when the surfaces move. It may also have the function of transmitting forces, t ... reduce cutting forces. References Further reading * * * Condensed matter physics Surface science {{CMP-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogen Sulfide
Hydrogen sulfide is a chemical compound with the formula . It is a colorless chalcogen-hydride gas, and is poisonous, corrosive, and flammable, with trace amounts in ambient atmosphere having a characteristic foul odor of rotten eggs. The underground mine gas term for foul-smelling hydrogen sulfide-rich gas mixtures is ''stinkdamp''. Swedish chemist Carl Wilhelm Scheele is credited with having discovered the chemical composition of purified hydrogen sulfide in 1777. The British English spelling of this compound is hydrogen sulphide, a spelling no longer recommended by the Royal Society of Chemistry or the International Union of Pure and Applied Chemistry. Hydrogen sulfide is toxic to humans and most other animals by inhibiting cellular respiration in a manner similar to hydrogen cyanide. When it is inhaled or it or its salts are ingested in high amounts, damage to organs occurs rapidly with symptoms ranging from breathing difficulties to convulsions and death. Despite this, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulfide Stress Cracking
Sulfide stress cracking (SSC) is a form of hydrogen embrittlement which is a cathodic cracking mechanism. It should not be confused with the term stress corrosion cracking which is an anodic cracking mechanism. Susceptible alloys, especially steels, react with hydrogen sulfide (), forming metal sulfides (MeS) and atomic hydrogen (H•) as corrosion byproducts. Atomic hydrogen either combines to form H2 at the metal surface or diffuses into the metal matrix. Since sulfur is a hydrogen recombination poison, the amount of atomic hydrogen which recombines to form H2 on the surface is greatly reduced, thereby increasing the amount of diffusion of atomic hydrogen into the metal matrix. This aspect is what makes wet H2S environments so severe.Foroulis Z.A ed., High-Temperature Metallic Corrosion by Sulfur and Its Compounds, The Electrochemical Society, Princeton, NJ. (1970) Conference proceedings Since SSC is a form of hydrogen embrittlement, it is most susceptibile to cracking at or s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Steel
Steel is an alloy made up of iron with added carbon to improve its strength and fracture resistance compared to other forms of iron. Many other elements may be present or added. Stainless steels that are corrosion- and oxidation-resistant typically need an additional 11% chromium. Because of its high tensile strength and low cost, steel is used in buildings, infrastructure, tools, ships, trains, cars, machines, electrical appliances, weapons, and rockets. Iron is the base metal of steel. Depending on the temperature, it can take two crystalline forms (allotropic forms): body-centred cubic and face-centred cubic. The interaction of the allotropes of iron with the alloying elements, primarily carbon, gives steel and cast iron their range of unique properties. In pure iron, the crystal structure has relatively little resistance to the iron atoms slipping past one another, and so pure iron is quite ductile, or soft and easily formed. In steel, small amounts of carbon, other ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zinc
Zinc is a chemical element with the symbol Zn and atomic number 30. Zinc is a slightly brittle metal at room temperature and has a shiny-greyish appearance when oxidation is removed. It is the first element in group 12 (IIB) of the periodic table. In some respects, zinc is chemically similar to magnesium: both elements exhibit only one normal oxidation state (+2), and the Zn2+ and Mg2+ ions are of similar size.The elements are from different metal groups. See periodic table. Zinc is the 24th most abundant element in Earth's crust and has five stable isotopes. The most common zinc ore is sphalerite (zinc blende), a zinc sulfide mineral. The largest workable lodes are in Australia, Asia, and the United States. Zinc is refined by froth flotation of the ore, roasting, and final extraction using electricity ( electrowinning). Zinc is an essential trace element for humans, animals, plants and for microorganisms and is necessary for prenatal and postnatal development. It ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
