An alloy is a blend of two or more metals. the blend can form a solid solution or it can be simple mixture, depending on the size of the crystals that form and how the homogenous alloy is
Many people believe steel is an alloy of iron and nickel, but actually steel is an alloy consisting primarily of iron, always with some carbon, with any of several metals
Stainless steel is an alloy of iron, low levels of carbon, and chromium. the chromium gives the steel resistance to “strain”or iron rust. A thin layer of chromium oxide forms on the surfaceof stainless steel, protecting it from oxygen, which is what causes rust. However, stainless steel can be stained if you expose it to a corrosive environments, such as sea water. the corrosive environment attacks and removes the protective chromium oxides coating more quickly than it can repair itself, exposing the iron to attack.
Brass is an alloy consisting primarily of copper and zinc. bronze, on the other hand, is an alloy of copper with another metals, usually tin. originally, brass is any copper alloy, but in modern usage, brass is any copper alloy.
An amalgam is an alloy made by combining mercury with another metal.almost all metals form amalgams, with the expection of iron. Amalgam is used in dentistry and in gold and silver mining because these metals readily combine with mercury.
Alloy are metallic compound composed of one metal and one or more metal, or non metal element
example of common alloy include:
steel, a combination of iron(metal) and carbon (non metal)
Bronze, a combination of copper(metal) and tin (metal) and
Brass, a mixture of copper(metal) and zinc(metal)
Individual pure metals may posses useful properties, such as good electrical conductivity, high strength and hardness, or heat and corrosion resistance
Commercial metal alloys attempt to combine these beneficial properties in order to create a metal that is more useful for a particular application than ny of its com[ponent elements
The development of steels, for example finding the right combination of carbon and iron(about 99% iron and 1% carbon, as it turns out) in order to produce a metal that is stronger, lighter and more workable meatl than pure iron
Thousand of alloys compositions are in regular production, while new composition are developed regularly.accepted standard composition include the purity levels of constituent elements.themake-up, as well as mechanical and physical properties for common alloy are monitored by international organisation such as ISO,SAE INTERNATIONAL and ASTM INTERNATIONAL.
A polymer is a chemical compound where molecules are bonded together are bonded together in repeating chains. These materials, polymers, have unique properties and can be tailored depending on their intended purpose.
Polymer are both man made and are naturally occurring.for example, rubber is a naturally occurring. For example, rubber is a natural polymeric material that is extremely useful and has been used by man for thousands of years. Rubber has excellent elastic properties, and this is a result of the molecular polymer chain created by mother nature. bothman made and natural polymers can exhibit elastic properties, however polymer can exhibit a wide range of additional useful properties. Depending on the desired use, polymers can be finely tuned to leverage the advantageous property.
2. Impact resistant
Polymerisation is the method of creating a synthetic polymer by combining many small monomer molecules into chain held together by covalent bonds. these are two major forms of polymerisation, step growth polymerisation. the main difference between the two form of polymerisation is that in that chain growth polymerisation, monomer molecules are added to the chain one at a time.
The processing of polymeric materials plastic elastomers and composites is characterised by a wide variety of distinct methods of techniques. techniques involving the continuous manufacture of a product basically have uniform cross section, which include extrusion, extrusion covering, film blowing and calendaring. Technique involving the the shaping of a deformable polymer perform against a mold surface, which involve coating and rotational molding and finally technique which involve the complete filing of a mold cavity, and include casting, compression molding, transfer molding, injection molding and reaction injection molding
The extrusion process basically is continuously shaping a fluid polymer through the orifice of a suitable tool and subsequently solidifying it into a product.in this case of thermoplastic, the feed material, in powder or pellent form, is most commonly heated to a fluid state and pumped into the die,through a screw extruder; it is then solidified by cooling after exiting from the die
Extrusion products frae often sub divided into groups that include filaments of circular cross section,profiles of irregular cross section,axisymmetric tubes and pipes, and flat products such as films and sheets.
polymer matrix composite
it is the material consisting of a polymer matrix combined with a fibrous reinforcing dispersed phase
modern composites are classified into three according to the matrix materials: polymer, metal, or ceramic. since the polymeric materials tend to degrade at elevated temperature,polymer matrix composites are restricted to secondary structure in which operating temperature are lower than 300 degree Celsius for higher temperature, metal matrix and ceramic matrix
high fracture stiffness
good abrasion resistnce
good corrosion resistance
Low thermal resistance
High coefficient of thermal expansion
Properties of fibre
Orientation of fibre
Concentration of fibres
Fibre may be arranged in unidirectional fibres; rovings; veil mat:thin pile of randomly orientated and looped continuous fibers;
Woven fibres; chopped strands; thin pile of randomly oriented and looped short fibres..
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