"$100,000,000 per gram, due to its scarcity and micro-scale production. Some metals and metal alloys possess high structural strength per unit mass, making them useful materials for carrying large loads or resisting impact damage. Metal alloys can be engineered to have high resistance to shear, torque and deformation. However the same metal can also be vulnerable to fatigue damage through repeated use or from sudden stress failure when a load capacity is exceeded. The strength and resilience of metals has led to their frequent use in high-rise building and bridge construction, as well as most vehicles, many appliances, tools, pipes,"
"Environmental stress fracture In materials science, environmental stress fracture or environment assisted fracture is the generic name given to premature failure under the influence of tensile stresses and harmful environments of materials such as metals and alloys, composites, plastics and ceramics. Metals and alloys exhibit phenomena such as stress corrosion cracking, hydrogen embrittlement, liquid metal embrittlement and corrosion fatigue all coming under this category. Environments such as moist air, sea water and corrosive liquids and gases cause environmental stress fracture. Metal matrix composites are also susceptible to many of these processes. Plastics and plastic-based composites may suffer swelling, debonding and"
"Stress corrosion cracking Stress corrosion cracking (SCC) is the growth of crack formation in a corrosive environment. It can lead to unexpected sudden failure of normally ductile metals subjected to a tensile stress, especially at elevated temperature. SCC is highly chemically specific in that certain alloys are likely to undergo SCC only when exposed to a small number of chemical environments. The chemical environment that causes SCC for a given alloy is often one which is only mildly corrosive to the metal. Hence, metal parts with severe SCC can appear bright and shiny, while being filled with microscopic cracks. This"
"Fracture strength or breaking strength is the stress when a specimen fails or fractures. A detailed understanding of how fracture occurs in materials may be assisted by the study of fracture mechanics. Fracture strength, also known as breaking strength, is the stress at which a specimen fails via fracture. This is usually determined for a given specimen by a tensile test, which charts the stress–strain curve (see image). The final recorded point is the fracture strength. Ductile materials have a fracture strength lower than the ultimate tensile strength (UTS), whereas in brittle materials the fracture strength is equivalent to the"
"on one of the tie bar links of one of the suspension chains, and the whole joint failed quickly by overload. The event escalated and the whole bridge disappeared in less than a minute, killing 46 drivers or passengers on the bridge at the time. Environmental stress fracture In materials science, environmental stress fracture or environment assisted fracture is the generic name given to premature failure under the influence of tensile stresses and harmful environments of materials such as metals and alloys, composites, plastics and ceramics. Metals and alloys exhibit phenomena such as stress corrosion cracking, hydrogen embrittlement, liquid metal"
"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. This occurs in the following ways: The main mechanism of transport for SMIE is surface self-diffusion of the embrittler over"
"more rust from forming, the conservators choose to keep the ""H.L. Hunley"" submerged in a water tank, instead of exposing it to the oxygen-rich air, until a full conservation plan could be created. Metal Fatigue (Stress and Corrosion) can be either from stress or corrosion. Stress fatigue occurs when the metal is repeatedly pushed back and forth, such as from water pressure. This pressure eventually cause tiny cracks to form in the metal. Corrosion fatigue happens when the cracks in the metal becomes corrosive and weaken the structure. Thus normal wear and tear can cause metal fatigue. The combination of"
"Thermal stress Thermal stress is stress created by any change in temperature to a material. These stresses can lead to fracture or plastic deformation depending on the other variables of heating, which include material types and constraints. Temperature gradients, thermal expansion or contraction and thermal shocks are things that can lead to thermal stress. This type of stress is highly dependent on the thermal expansion coefficient which varies from material to material. In general the larger the temperature change, the higher the level of stress that can occur. When a material is rapidly heated or cooled, the surface and internal"
"Metal A metal (from Greek μέταλλον ""métallon"", ""mine, quarry, metal"") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. Metals are typically malleable (they can be hammered into thin sheets) or ductile (can be drawn into wires). A metal may be a chemical element such as iron, or an alloy such as stainless steel. In physics, a metal is generally regarded as any substance capable of conducting electricity at a temperature of absolute zero. Many elements and compounds that are not normally classified as metals become metallic under"
"break or shatter under stress cannot be manipulated using metal-forming processes such as hammering, rolling, drawing or extruding. Malleable materials can be formed cold using stamping or pressing, whereas brittle materials may be cast or thermoformed. High degrees of ductility occur due to metallic bonds, which are found predominantly in metals, leading to the common perception that metals are ductile in general. In metallic bonds valence shell electrons are delocalized and shared between many atoms. The delocalized electrons allow metal atoms to slide past one another without being subjected to strong repulsive forces that would cause other materials to shatter."
"Oxide jacking The expansive force of rusting, which may be called oxide jacking or rust burst, is a phenomenon that can cause damage to structures made of stone, masonry, concrete or ceramics, and reinforced with metal components. A definition is ""the displacement of building elements due to the expansion of iron and steel products as the metal rusts and becomes iron oxide"". Corrosion of other metals such as aluminum can also cause oxide jacking. According to metallurgist Jack Harris, ""Oxidation is usually accompanied by a net expansion so that when it occurs in a confined space stresses are generated in"
"stress. Some materials may exhibit a marked decrease in their load carrying capacity and fail in a brittle fashion when stressed in an atmosphere containing hydrogen. Both of these processes may be called hydrogen embrittlement. Hydrogen embrittlement may occur as a side effect of electroplating processes. Delayed failure, the fracture of a component under stress after an elapsed time, is a characteristic feature of hydrogen embrittlement (2). Hydrogen entry into the material may be affected during melting, casting, welding, and service life. Corrosion during service in moist environments generates hydrogen, part of which may enter the metal and cause embrittlement."
"Stress fracture Stress fracture is a fatigue-induced fracture of the bone caused by repeated stress over time. Instead of resulting from a single severe impact, stress fractures are the result of accumulated trauma from repeated submaximal loading, such as running or jumping. Because of this mechanism, stress fractures are common overuse injuries in athletes. Stress fractures can be described as very small slivers or cracks in the bone; and are sometimes referred to as ""hairline fractures."" Stress fractures most frequently occur in weight-bearing bones, such as the tibia (bone of the lower leg), metatarsals, and navicular bones (bones of the"
"as well as the mechanical stresses that they experience. Often a combination of both environmental conditions and stress will cause failure. Metal components are designed to withstand the environment and stresses that they will be subjected to. The design of a metal component involves not only a specific elemental composition but also specific manufacturing process such as heat treatments, machining processes, etc.… The huge arrays of different metals that result all have unique physical properties. Analysis of a failed part can be done using destructive testing or non-destructive testing. Destructive testing involves removing a metal component from service and sectioning"
"portion. The term ""stress raiser"" is used in orthopedics; a focus point of stress on an implanted orthosis is very likely to be its point of failure. Classic cases of metal failures due to stress concentrations include metal fatigue at the corners of the windows of the De Havilland Comet aircraft and brittle fractures at the corners of hatches in Liberty ships in cold and stressful conditions in winter storms in the Atlantic Ocean. The maximum stress felt near a crack occurs in the area of lowest radius of curvature. In an elliptical crack of length formula_1 and width formula_2,"
"Fracture A fracture is the separation of an object or material into two or more pieces under the action of stress. The fracture of a solid usually occurs due to the development of certain displacement discontinuity surfaces within the solid. If a displacement develops perpendicular to the surface of displacement, it is called a normal tensile crack or simply a crack; if a displacement develops tangentially to the surface of displacement, it is called a shear crack, slip band, or dislocation. Brittle fractures occur with no apparent deformation before fracture; ductile fractures occur when visible deformation does occur before separation."
"Stress concentration A stress concentration (often called stress raisers or stress risers) is a location in an object where stress is concentrated. An object is stronger when force is evenly distributed over its area, so a reduction in area, e.g., caused by a crack, results in a localized increase in stress. A material can fail, via a propagating crack, when a concentrated stress exceeds the material's theoretical cohesive strength. The real fracture strength of a material is always lower than the theoretical value because most materials contain small cracks or contaminants (especially foreign particles) that concentrate stress. Fatigue cracks always"
"internal defects and create bubbles within the material. The stress caused by the expanding bubble in addition to the applied stress is what lowers the overall stress required to fracture the material. The hydrogen attack method is similar to the pressure theory, but in this case it is suspected that the hydrogen reacts with carbon in the steel to form methane, which then forms blisters and bubbles at the surface. In this case, the added stress by the bubbles is enhanced by the decarburization of the steel, which weakens the metal. In addition to hydrogen embrittlement, radiation induced creep can"
"Metal dusting Metal dusting is ""a catastrophic form of corrosion that occurs when susceptible materials are exposed to environments with high carbon activities."" The corrosion manifests itself as a break-up of bulk metal to metal powder. The suspected mechanism is firstly the deposition of a graphite layer on the surface of the metal, usually from carbon monoxide (CO) in the vapour phase. This graphite layer is then thought to form metastable MC species (where M is the metal), which migrate away from the metal surface. However, in some regimes no MC species are observed indicating a direct transfer of metal"
"be introduced during fabrication, coatings, testing or during service of the material components. Susceptibility for SMIE increases with the following material characteristics: 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"
"environments. ""High Temperature Hydrogen Attack"" does not rely on atomic hydrogen. At high temperature and high hydrogen partial pressure, hydrogen can diffuse into carbon steel alloys. In susceptible alloys, the hydrogen combines with carbon within the alloy and forms methane. The methane molecules create a pressure buildup in the metal lattice voids, which leads to embrittlement and even cracking of the metal. Sulfidic corrosion, also known as sulfidation, is the term used for high temperature corrosion (above 450F / above approx. 260°C) of steel in contact with sulfur (Fe reacts with S to form FeS). Sulfide stress cracking Sulfide stress"
"Fatigue (material) In materials science, fatigue is the weakening of a material caused by repeatedly applied loads. It is the progressive and localized structural damage that occurs when a material is subjected to cyclic loading. The nominal maximum stress values that cause such damage may be much less than the strength of the material typically quoted as the ultimate tensile stress limit, or the yield stress limit. Fatigue occurs when a material is subjected to repeated loading and unloading. If the loads are above a certain threshold, microscopic cracks will begin to form at the stress concentrators such as the"
"Mechanical overload The failure or fracture of a product or component as a result of a single event is known as mechanical overload. It is a common failure mode, and may be contrasted with fatigue, creep, rupture, or stress relaxation. The terms are used in forensic engineering and structural engineering when analysing product failure. Failure may occur because either the product is weaker than expected owing to a stress concentration, or the applied load is greater than expected and exceeds the normal tensile strength, shear strength or compressive strength of the product. Examples include the many components which fail in"
"Brittleness A material is brittle if, when subjected to stress, it breaks without significant plastic 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 (which do not deform plastically) and some polymers, such as PMMA and polystyrene. Many steels become brittle at low temperatures (see ductile-brittle transition temperature), depending on their composition and processing. When used in materials science, it is generally applied to materials that fail when there is little or no plastic deformation before failure. One proof"
"Presence of a tensile stress, either inherent or externally applied, is necessary for metals to be damaged. As in the case of stress corrosion cracking, hydrogen embrittlement may also lead to a decrease in the threshold stress intensity factor for crack propagation or an increase in the sub critical crack growth velocity of the material. The most visible effect of hydrogen in materials is a drastic reduction in ductility during tensile tests. It may increase, decrease or leave unaffected the yield strength of the material. Hydrogen may cause serrated yielding in certain metals such as niobium, nickel and some steels"
"an unstressed state. Metallurgists typically use the term Stress corrosion cracking or Environmental stress fracture to describe this type of failure in metals. Although the phenomenon of ESC has been known for a number of decades, research has not yet enabled prediction of this type of failure for all environments and for every type of polymer. Some scenarios are well known, documented or are able to be predicted, but there is no complete reference for all combinations of stress, polymer and environment. The rate of ESC is dependent on many factors including the polymer’s chemical makeup, bonding, crystallinity, surface roughness,"
"fatigue of the metal causing a type of wear also called ""cavitation"". The most common examples of this kind of wear are to pump impellers, and bends where a sudden change in the direction of liquid occurs. Cavitation is usually divided into two classes of behavior: inertial (or transient) cavitation and non-inertial cavitation. Inertial cavitation is the process where a void or bubble in a liquid rapidly collapses, producing a shock wave. Inertial cavitation occurs in nature in the strikes of mantis shrimps and pistol shrimps, as well as in the vascular tissues of plants. In man-made objects, it can"
"don't are ""strong"". In reality, many materials that undergo large elastic and plastic deformations, such as steel, are able to absorb stresses that would cause brittle materials, such as glass, with minimal plastic deformation ranges, to break. Deformation (engineering) In materials science, deformation refers to any changes in the shape or size of an object due to The first case can be a result of tensile (pulling) forces, compressive (pushing) forces, shear, bending or torsion (twisting). In the second case, the most significant factor, which is determined by the temperature, is the mobility of the structural defects such as grain"
"of two forms. One is rupture of the vessel, normally by crack propagation. Cracks in steel under stress can spread at speeds of up to more than a mile per second. This results in the release of stored energy, one effect of which is the acceleration of the rupture itself. Such releases are effectively explosions. The other form is the failure of a mechanical safety device, such as the interlock that disables the door opening mechanism as long as vessel pressure exceeds a conservative value, such as ¼ or ½ psi. Less commonly, there can be a failure in the"
"temperature causes stresses on the surface that are in tension, which encourages crack formation and propagation. Ceramics materials are usually susceptible to thermal shock. An example is when glass is heated up to a high temperature and then quickly quenched in cold water. As the temperature of the glass falls rapidly, stresses are induced and causes fractures in the body of the glass which can be seen as cracks or even shattering in some cases. Thermal stress Thermal stress is stress created by any change in temperature to a material. These stresses can lead to fracture or plastic deformation depending"
"it. The practical significance of liquid metal embrittlement is revealed by the observation that several steels experience ductility losses and cracking during hot-dip galvanizing or during subsequent fabrication. Cracking can occur catastrophically and very high crack growth rates have been measured. Similar metal embrittlement effects can be observed even in the solid state, when one of the metals is brought close to its melting point; e.g. cadmium-coated parts operating at high temperature. This phenomenon is known as solid metal embrittlement. Liquid metal embrittlement or LME is characterized by the reduction in the threshold stress intensity, true fracture stress or in"
"Delamination Delamination is a mode of failure for composite materials and steel. In laminated materials, repeated cyclic stresses, impact, and so on can cause layers to separate, forming a mica-like structure of separate layers, with significant loss of mechanical toughness. Delamination also occurs in reinforced concrete structures subject to reinforcement corrosion, in which case the oxidized metal of the reinforcement is greater in volume than the original metal. The oxidized metal therefore requires greater space than the original reinforcing bars, which causes a wedge-like stress on the concrete. This force eventually overcomes the relatively weak tensile strength of concrete, resulting"
"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 and atomic hydrogen as corrosion byproducts. Atomic hydrogen either combines to form H 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 H on the surface is greatly reduced, thereby increasing the amount of diffusion of"