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Aluminium–silicon Alloys
Aluminium–silicon alloys or Silumin is a general name for a group of lightweight, high-strength aluminium alloys based on an aluminum–silicon system (AlSi) that consist predominantly of aluminum – with silicon as the quantitatively most important alloying element. Pure AlSi alloys cannot be hardened, the commonly used alloys AlSiCu (with copper) and AlSiMg (with magnesium) can be hardened. The hardening mechanism corresponds to that of AlCu and AlMgSi. AlSi alloys are by far the most important of all aluminum cast materials. They are suitable for all casting processes and have excellent casting properties. Important areas of application are in car parts, including engine blocks and pistons. In addition, their use as a functional material for high-energy heat storage in electric vehicles is currently being focused on. Alloying elements Aluminium-silicon alloys typically contain 3% to 25% silicon content. Casting is the primary use of aluminum-silicon alloys, but they ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aluminium Alloy
An aluminium alloy ( UK/IUPAC) or aluminum alloy ( NA; see spelling differences) is an alloy in which aluminium (Al) is the predominant metal. The typical alloying elements are copper, magnesium, manganese, silicon, tin, nickel and zinc. There are two principal classifications, namely casting alloys and wrought alloys, both of which are further subdivided into the categories heat-treatable and non-heat-treatable. About 85% of aluminium is used for wrought products, for example rolled plate, foils and extrusions. Cast aluminium alloys yield cost-effective products due to their low melting points, although they generally have lower tensile strengths than wrought alloys. The most important cast aluminium alloy system is Al–Si, where the high levels of silicon (4–13%) contribute to give good casting characteristics. Aluminium alloys are widely used in engineering structures and components where light weight or corrosion resistance is required.I. J. Polmear, ''Light Alloys'', A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solidification
Freezing is a phase transition in which a liquid turns into a solid when its temperature is lowered below its freezing point. For most substances, the melting and freezing points are the same temperature; however, certain substances possess differing solid-liquid transition temperatures. For example, agar displays a Hysteresis#Liquid–solid-phase transitions, hysteresis in its melting point and freezing point. It melts at and solidifies from . Crystallization Most liquids freeze by crystallization, formation of crystal, crystalline solid from the uniform liquid. This is a first-order thermodynamic phase transition, which means that as long as solid and liquid coexist, the temperature of the whole system remains very nearly equal to the melting point due to the slow removal of heat when in contact with air, which is a poor heat conductor. Because of the latent heat of fusion, the freezing is greatly slowed and the temperature will not drop anymore once the freezing starts but ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Engine Block
In an internal combustion engine, the engine block is the structure that contains the cylinders and other components. The engine block in an early automotive engine consisted of just the cylinder block, to which a separate crankcase was attached. Modern engine blocks typically have the crankcase integrated with the cylinder block as a single component. Engine blocks often also include elements such as coolant passages and oil galleries. The term "cylinder block" is often used interchangeably with "engine block". However, technically, the block of a modern engine (i.e., multiple cylinders integrated with another component) would be classified as a monobloc. __TOC__ Construction The main structure of an engine typically consists of the cylinders, coolant passages, oil galleries, crankcase, and cylinder head(s). The first production engines of the 1880s to 1920s usually used separate components for each element, which were bolted together during engine assembly. Modern en ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cylinder Liner
In an engine, the cylinder is the space in which a piston travels. The inner surface of the cylinder is formed from either a thin metallic liner (also called "sleeve") or a surface coating applied to the engine block. A piston is seated inside each cylinder by several metal piston rings, which also provide seals for compression and the lubricating oil. The piston rings do not actually touch the cylinder walls, instead they ride on a thin layer of lubricating oil. Steam engines The cylinder in a steam engine is made pressure-tight with end covers and a piston; a valve distributes the steam to the ends of the cylinder. Cylinders were cast in cast iron and later in steel. The cylinder casting can include other features such as valve ports and mounting feet. Internal combustion engines The cylinder is the space through which the piston travels, propelled by the energy generated from the combustion of the air/fuel mixture in the combustion chamber. In an air-cooled engine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypereutectic Piston
A hypereutectic piston is an internal combustion engine piston cast using a hypereutectic aluminum alloy with silicon content greater than the eutectic point of 12 weight percent silicon. Most aluminum-silicon casting alloys are hypoeutectic, meaning the silicon content is lower than the eutectic point, and contain relatively fine elemental silicon crystals formed through the eutectic reaction during solidification. In addition to fine silicon crystals, hypereutectic alloys also contain large primary silicon crystals that form before the eutectic reaction. As a result it contains a much higher phase fraction of silicon. Consequently, hypereutectic aluminum has a lower coefficient of thermal expansion, which allows engine designers to specify much tighter tolerances. The silicon content of these alloys is typically 16-19 weight percent, and above this content the mechanical properties and castability degrade substantially. Special molds, casting, and cooling techniques are required ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alusil
Alusil as a hypereutectic aluminium-silicon alloy (EN AC-AlSi17Cu4Mg / EN AC-48100 or A390) contains approximately 78% aluminium and 17% silicon. This alloy was theoretically conceived in 1927 by Schweizer & Fehrenbach, of Badener Metall-Waren-Fabrik, but practically created only by Lancia in the same year, for its car engines. It was further developed by Reynolds, now Rheinmetall Automotive. In the United States, Chevrolet was the first to use Reynolds A390 in the Chevrolet Vega. The Alusil aluminium alloy is commonly used to make linerless aluminium alloy engine blocks. There is no coating applied to the cylinder bore and blocks are not honed conventionally. During the manufacturing process, a chemical or mechanical process is used to remove aluminum from the surface of the cylinder bore, exposing a very hard silicon precipitate. These exposed silicon particles, which under a microscope look like small islands, allow for oil to collect in the area surrounding them, thus form ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shrinkage (casting)
In metalworking and jewelry making, casting is a process in which a liquid metal is delivered into a mold (usually by a crucible) that contains a negative impression (i.e., a three-dimensional negative image) of the intended shape. The metal is poured into the mold through a hollow channel called a sprue. The metal and mold are then cooled, and the metal part (the ''casting'') is extracted. Casting is most often used for making complex shapes that would be difficult or uneconomical to make by other methods. Casting processes have been known for thousands of years, and have been widely used for sculpture (especially in bronze), jewelry in precious metals, and weapons and tools. Highly engineered castings are found in 90 percent of durable goods, including cars, trucks, aerospace, trains, mining and construction equipment, oil wells, appliances, pipes, hydrants, wind turbines, nuclear plants, medical devices, defense products, toys, and more. Traditional techniques include los ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hot Cracking
A casting defect is an undesired irregularity in a metal casting process. Some defects can be tolerated while others can be repaired, otherwise they must be eliminated. They are broken down into five main categories: ''gas porosity'', ''shrinkage defects'', ''mould material defects'', ''pouring metal defects'', and ''metallurgical defects''. Terminology The terms "defect" and "" refer to two specific and separate things in castings. Defects are defined as conditions in a casting that must be corrected or removed, or the casting must be rejected. Discontinuities, also known as "imperfections", are defined as "interruptions in the physical continuity of the casting". Therefore, if the casting is less than perfect, but still useful and in tolerance, the imperfections should be deemed "discontinuities". Types There are many types of defects which result from many different causes. Some of the solutions to certain defects can be the cause for another type of defect. The following def ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eutectic System
A eutectic system or eutectic mixture ( ) is a type of a homogeneous mixture that has a melting point lower than those of the constituents. The lowest possible melting point over all of the mixing ratios of the constituents is called the ''eutectic temperature''. On a phase diagram, the eutectic temperature is seen as the eutectic point (see plot on the right). Non-eutectic mixture ratios have different melting temperatures for their different constituents, since one component's lattice will melt at a lower temperature than the other's. Conversely, as a non-eutectic mixture cools down, each of its components solidifies into a lattice at a different temperature, until the entire mass is solid. A non-eutectic mixture thus does not have a single melting/freezing point temperature at which it changes phase, but rather a temperature at which it changes between liquid and slush (known as the liquidus) and a lower temperature at which it changes between slush and solid (the solidu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diagramme Binaire Al Si Fonderie
A diagram is a symbolic representation of information using visualization techniques. Diagrams have been used since prehistoric times on walls of caves, but became more prevalent during the Enlightenment. Sometimes, the technique uses a three-dimensional visualization which is then projected onto a two-dimensional surface. The word ''graph'' is sometimes used as a synonym for diagram. Overview The term "diagram" in its commonly used sense can have a general or specific meaning: * ''visual information device'' : Like the term "illustration", "diagram" is used as a collective term standing for the whole class of technical genres, including graphs, technical drawings and tables. * ''specific kind of visual display'' : This is the genre that shows qualitative data with shapes that are connected by lines, arrows, or other visual links. In science the term is used in both ways. For example, Anderson (1997) stated more generally: "diagrams are pictorial, yet abstract, representatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
