Muhammad Sajjad BSME-01113138 Muhammad Umer BSME-01113128 Hafiz Sarmad BSME-01113100Section:CMechanical EngineeringThe University Of Lahore
Two inherently different materials that whencombined together produce a material withproperties that exceed the constituentmaterials.OR A combination of two or more simple materialsto yield another material with better properties.
One of the first fiber-reinforced polymercomposites made by humans was araincoat, created in the middle of thenineteenth century, by a Scottish fellowby the name of Charles Macintosh, whocame up with a clever idea.
He took two layers of cottonfabric and embedded themin natural rubber, making athree-layered sandwich.Remember, cotton is a formof a natural polymer calledcellulose. This made forgood raincoatsbecause, while the rubbermade it waterproof, thecotton layers made itcomfortable to wear.
Metal Matrix CompositesComposites arecombinations of twomaterials in which one ofthe material is called thereinforcing phase, is inthe form offibers, sheets, orparticles, and isembedded in the othermaterial called the matrixphase.Composite = matrix +
Typically, reinforcing materials are strongwith low densities while the matrix isusually a ductile or tough material. If thecomposite is designed and fabricatedcorrectly, it combines the strength of thereinforcement with the toughness of thematrix to achieve a combination of desirableproperties not available in any singleconventional material.
Metal Matrix compositesComposites are usuallymade of two parts, a fiberand a matrix. The fibercan be glass, carbonfiber, or polyethylene.The matrix, which is thestuff that holds thefibers, is usually athermoset like an epoxyresin.
The fiber is embedded in the matrix in order tomake the matrix stronger. Fiber-reinforcedcomposites have two things going for them.They are strong and light. They are oftenstronger than steel, but weigh much less. Thismeans that composites can be used to makeautomobiles lighter. Composites can also be used to imitate naturalmaterials, like in musical instruments whereuse of wood is common.
Aligned FibersThe properties of alignedfiber-reinforcedcomposite materials arehighly anisotropic. Thelongitudinal tensilestrength will be highwhereas the transversetensile strength can bemuch less than even thematrix tensile strength.
Random FibersThis is also calleddiscrete fibers. Thestrength will not beas high as withalignedfibers, however, theadvantage is that thematerial willbe istropic andcheaper.
Woven FibersThe fibers arewoven into afabric which islayered with thematrix material tomake a laminatedstructure.
Superior mechanical properties in comparisonto short fiber composites (higher modulus,higher impact properties, higher tensilestrength); elastic properties ~70-90% that ofcontinuous fiber composites.
PolyesterPolyesters have goodmechanicalproperties, electricalproperties and chemicalresistance. Polyestersare amenable to multiplefabrication techniquesand are low cost.
Vinyl EstersVinyl Esters are similar topolyester in performance.Vinyl esters have increasedresistance to corrosiveenvironments as well as ahigh degree of moistureresistance.
EpoxyEpoxies have improvedstrength and stiffnessproperties over polyesters.Epoxies offer excellentcorrosion resistance andresistance to solvents andalkalis. Cure cycles areusually longer thanpolyesters, however no by-products are produced.
• The advantages ofcomposite materialsare that they arestrong, don’t rusteasily and they arenot heavy in anyway.
• The disadvantagesof compositematerials are thatthey are veryexpensive to buyand difficult to stickto other materials.
• The people whowork with compositematerials are :-*Footballers*Ice skaters*Basket ball players*Pilots*Builders etc.
Liquid state fabrication of Metal MatrixComposites involves incorporation ofdispersed phase into a molten matrix metal,followed by its Solidification. In order to provide high level of mechanicalproperties of the composite, good interfacialbonding (wetting) between the dispersed phaseand the liquid matrix should be obtained.
Stir Casting Infiltration Gas Pressure Infiltration Squeeze Casting Infiltration Pressure Die Infiltration
Stir Casting is a liquid state method ofcomposite materials fabrication, in which adispersed phase (particles, short fibers) ismixed with a molten matrix metal by means ofmechanical stirring. Stir Casting is the simplest and the most costeffective method of liquid state fabrication. The liquid composite material is then cast byconventional casting methods and may also beprocessed by conventional Metal formingtechnologies.
Stir Casting is characterizedby the following features:Content of dispersed phase islimited (usually not morethan 30 vol.%).Distribution of dispersedphase throughout the matrixnot perfectly homogeneous.The technology is relativelysimple and low cost.
InfiltrationInfiltration is a liquidstate method ofcomposite materialsfabrication, in which apreformed dispersedphase(particles, fibers, woven)is soaked in a moltenmatrix metal, which fillsthe space between thedispersed phaseinclusions.
Gas Pressure Infiltration is a forced infiltrationmethod of liquid phase fabrication of MetalMatrix Composites, using a pressurized gas forapplying pressure on the molten metal andforcing it to penetrate into a preformeddispersed phase.
Gas Pressure Infiltration method is used formanufacturing large composite parts. The method allows using non-coated fibers dueto short contact time of the fibers with the hotmetal. In contrast to the methods using mechanicalforce, Gas Pressure Infiltration results in lowdamage of the fibers.
Squeeze Casting Infiltration is a forcedinfiltration method of liquid phase fabricationof Metal Matrix Composites, using a movablemold part (ram) for applying pressure on themolten metal and forcing it to penetrate into aperformed dispersed phase, placed into thelower fixed mold part. Squeeze Casting Infiltration method is similarto the Squeeze casting technique used for metalalloys casting.
A preform of dispersed phase (particles, fibers) isplaced into the lower fixed mold half. A molten metal in a predetermined amount ispoured into the lower mold half. The upper movable mold half (ram) movesdownwards and forces the liquid metal to infiltratethe preform. The infiltrated material solidifies under thepressure. The part is removed from the mold by means ofthe ejector pin.
The method is used for manufacturing simplesmall parts (automotive engine pistons fromaluminum alloy reinforced by alumina shortfibers).
Pressure Die Infiltration is a forced infiltrationmethod of liquid phase fabrication of MetalMatrix Composites, using a Die castingtechnology, when a preformed dispersed phase(particles, fibers) is placed into a die (mold)which is then filled with a molten metalentering the die through a sprue andpenetrating into the preform under thepressure of a movable piston (plunger).
* Used in particle reinforcing- ceramics, glasses (small mineral particles)- metal particles (aluminium, and amorphousmaterials ) polymers and carbon black
Particles are used to increase the modulus ofthe matrix, to decrease the permeability of thematrix, to decrease the ductility of the matrixand also used to produce inexpensivecomposites.
Tennis rackets are most often made out of aluminumand composite materials. Aluminum rackets aremade of one of several alloys, including a 2 percentsilicon alloy with traces of magnesium, copper andchromium, and a 10 percent zinc alloy, withmagnesium, copper and chromium. Composite rackets contain a range of materials,including graphite, fiberglass, boron or Kevlar. Thestrings are made of nylon, twisted sheep, cow gut orsynthetic gut, but nylon is the most commonly used.
Fiber-reinforced Composites are made of:- metals, ceramics, glasses, or polymers that havebeen turned into graphite and known as carbonfibers.- Fibers increase the modulus of the matrixmaterial. (strong covalent bonds along the fibers lengthgives them a very high modulus in this direction becauseto break or extend the fiber the bonds must also be brokenor moved )
sports equipment, such as a time-trial racing bicycle framewhich consists of carbon fibers in a thermoset polymer matrix.Body parts of race cars and some automobiles are compositesmade of glass fibers (or fiberglass) in a thermoset matrixFiber orientation in fiberreinforced composites.
The properties ofstructural compositesdepend on:- Constituents- Geometrical design
Fiber Craft Industries in Lahore PakistanFiberglass reinforced Plastic pipes usuallyknown as FRP or GRP pipe. Textile Industries:Hussain Industries in MultanNishat Textile Mills in Faislabad and karachiChenab Group In Faislabad
Kowil Group of Industries Sialkot:Manufacturing Coat of Arms, Flags &Banners,, Ribbons, Buckles, MetalBadges, Buttons for Army, Navy, AirForce, Police, FireDepartment, Colleges, Schools etc.
S. K. Munir & Co. Lahore Manufacturing Uniform Items ( like Boots, Jackets, Belts etc.) Bullet proof Items (likeBullet proof Jackets, Helmets etc.) Wireless & Communication Equipment (likewalkie talkie, mobile radios , receivers etc.) Rescue & Safety Equipment (like fire fightingequipment, fire proof suits etc.
In general, the major advantages of MatrixComposites compared to unreinforcedmaterials, such as steel and other commonmetals, are as follows:
METAL MATRIX COMPOSITES STEEL Increased specificstrength and elevatedtemperature strength. High CorrosionResistance Much Costly. Strength reduces athigh temperaturesdue to fire. It can corrode. Not much Costly.
Carbon fiber is defined as a fiber containing atleast 92 wt % carbon, while the fiber containing atleast 99 wt % carbon is usually called a graphitefiber. It is a material consisting of several fibers andcomposed mostly of carbon atoms. Each fiber is about 5 – 10 μm thick in diameter.
The manufacturing of carbon fibers carriesa number of challenges, including: The need for more cost effective recovery andrepair. Close control required to ensure consistentquality. Health and safety issues Skin irritation Breathing irritation.
Carbon fiber is currently produced in relatively limitedquantities mostly via two manufacturing processes: Based on pitch (coal tar and petroleum products) Based on Polyacrylonitrile (PAN)o Current global capacity for pitch-based carbon fiber isestimated at about 3,500 metric tons per year. Global use for PAN-based carbon fiber is increasingrapidly, and total production capacity currently does notmeet the demand. PAN-based carbon fiber is more expensive toproduce, hence, limiting its use to high endapplications, (used primarily by aerospace and sportingequipment industries).
In the manufacturing process, the rawmaterial, which is called precursor, is drawn intolong strands or fibers. The fibers are woven intofabric or combined with other materials that aremolded into desired shapes and sizes. There are typically five segments in themanufacturing of carbon fibers from the PANprocess. These are:1)Spinning: PAN mixed with other ingredients and spun intofibers, which are washed and stretched.
Stabilizing:Chemical alteration to stabilize bonding.Carbonizing:Stabilized fibers heated to very hightemperature forming tightly bonded carboncrystals.Treating the Surface:Surface of fibers oxidized to improve bondingproperties.
Sizing:Fibers are coated and wound ontobobbins, which are loaded onto spinningmachines that twist the fibers into differentsize yarns. Instead of being woven intofabrics, fibers may be formed into composites.To form compositematerials, heat, pressure, or a vacuum bindsfibers together with a plastic polymer.
Portable power. Rechargeable batteries and fuel cellelectrodes. Fiber reinforced plastics, FRP. Energy production; windmill blades. Building and construction materials.
The future efforts on carbon fiber research willbe focused on cost reduction and propertyimprovement. The mechanical property of carbon fiber heavilyrelies on its microstructure. The improvement on the tensile, flexural, andshear strength of pitch carbon fibers has beenobserved by randomizing the graphitedistribution in the fiber transverse direction.
• Ceramics materials are inorganic and nonmetallicmaterials. most ceramics are compounds betweenmetallic and nonmetallic elements for which theinteratomic bonds are either totally ionic orpredominantly ionic but having same covalentcharacter
Slurry is a dispersion of ceramic particles in aliquid carrier, which may also contain additivessuch as binders and wetting agents.Slurry Infiltration method of fabrication ofCeramic Matrix Composites utilizes a slurrypercolating into a porous reinforcing preform. Theinfiltration process is driven by the capillaryforces.After the infiltration process has completed, thepreform is dried and hot pressed forming aceramic matrix composite.
Slurry infiltrationThe reinforcing fibers passe through aslurry, which penetrates into the porousstructure of the reinforcing phase. The drivingforce of the infiltration is capillary effect but theprocess may be enhanced by vacuum orpressure.
Lay-upThe fibers are wound onto a mandrel. Then itis dried, cut and laid-up. After drying they arecut and laid-up on a tooling (mold). Hot pressingHot pressing is performed at high temperatureand increased pressure, which enhance thediffusion of the ceramic material between theparticles incorporated into the fibers structure.The particles consolidate resulting in a lowporosity densified composite.
The reinforcing fibers may be damaged by thehigh pressure applied in the hot pressing stage. Hot pressing operation requires relativelyexpensive equipment. Relatively small and simple parts may befabricated.
Made from natural clays and mixturesof clays and added crystallineceramics.These include: Whitewares Structural Clay Products Refractory Ceramics
Firebricks for furnaces and ovens.Have high Silicon or Aluminiumoxide content.Brick products are used in themanufacturing plant for iron andsteel, non-ferrousmetals, glass, cements, ceramics, energy conversion, petroleum, andchemical industries.
Used to provide thermal protection of othermaterials in very high temperatureapplications, such as steel making(Tm=1500 C), metal foundry operations, etc. They are usually composed of alumina(Tm=2050 C) and silica along with otheroxides: MgO(Tm=2850 C), Fe2O3, TiO2, etc., and haveintrinsic porosity typically greater than 10%by volume. Specialized refractories, (those alreadymentioned) and BeO, ZrO2, mullite, SiC, andgraphite with low porosity are also used.
Main ingredient is Silica (SiO2) If cooled very slowly will form crystallinestructure. If cooled more quickly will form amorphousstructure consisting of disordered and linkedchains of Silicon and Oxygen atoms. This accounts for its transparency as it is thecrystal boundaries that scatter the light, causingreflection. Glass can be tempered to increase its toughnessand resistance to cracking.
Three common types of glass: Soda-lime glass - 95% of all glass,windows containers etc. Lead glass - contains lead oxide toimprove refractive index Borosilicate - contains Boron oxide,known as Pyrex.
The strength of glasscan be enhanced byinducing compressiveresidual stresses at thesurface.The surface stays incompression - closingsmall scratches andcracks.Small Scratches
Good electrical insulators and refractories.• Magnesium Oxide is used as insulationmaterial in heating elements and cables.• Aluminium Oxide• Beryllium Oxides• Boron Carbide• Tungsten Carbide.• Used as abrasives and cutting tool tips.
Used to produce concreteroads, bridges, buildings, dams.
Advanced ceramic materials have beendeveloped over the past half centuryApplied as thermal barrier coatings to protectmetal structures, wearing surfaces, or as integralcomponents by themselves. Engine applications are very common for thisclass of material which includes silicon nitride(Si3N4), silicon carbide (SiC), Zirconia (ZrO2) andAlumina (Al2O3) Heat resistance and other desirable propertieshave lead to the development of methods totoughen the material by reinforcement with fibersand whiskers opening up more applications forceramics
AutomotiveComponents inSilicon CarbideChosen for its heatand wearresistance
Ceramic armour systems are used to protectmilitary personnel and equipment. Advantage: low density of the material canlead to weight-efficient armour systems.Typical ceramic materials used in armoursystems include alumina, boron carbide, siliconcarbide, and titanium diboride. The ceramic material is discontinuous and issandwiched between a more ductile outer andinner skin.
Ceramic armour systems are used to protectmilitary personnel and equipment. Advantage: low density of the material can leadto weight-efficient armour systems. Typical ceramic materials used in armoursystems include alumina, boron carbide, siliconcarbide, and titanium diboride. The ceramic material is discontinuous and issandwiched between a more ductile outer andinner skin.
• Most of the impact energy is absorbed by thefracturing of the ceramic and any remainingkinetic energy is absorbed by the innerskin, that also serves to contain the fragmentsof the ceramic and the projectile preventingsevere impact with the personnel/equipmentbeing protected.• This lightweight solution provided an efficientand removable/replaceable armour system.Similar systems used on Armoured PersonnelCarrier’s.