GROUP # 08

TOPIC:

METAL MATRIX COMPOSITES.

&CERAMIC MATRIX

COMPOSITES

INTRODUCTON

Engineer traditional considered the metal the most important class of engineering materials, but interesting to know that composites are more appreciable and abundant use in nature.

COMPOSITES??? “Composites is a material composed two or more physically distinct

phases whose combination produce aggregate properties that are different from those of it’s constituents”

Question arises.

How commercial interest drives for composites??

Commercial interest in composites materials derive from their properties.

PROPERTIES OF COMPOSITES:

Very strong, stiff and lighter in weight. Strength to weight and stiffness to weight ration is several ties higher than steel. Have a corrosion resistance so use in automotive and other apllications. Fatigue properties are generally better than common engineering material. It is possible to achieve combination of properties not attainable with metals,

ceramics and polymers alone Very smooth and better appearance is controlled in certain cermamics.

EXAMPLES: Cemented carbide, rubber mixed with carbon black, Titanium carbide (TiC),

Chromium carbide (Cr3C2),Tantalum carbide (TaC) etc.

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CLASSIFICATION OF COMPOSITE MATERIALS Composites material consist of two distinct types by nature.Traditional composites:wood.Concrete.Bamboo.Adobe bricks. ( mud and straw).Synthetic composites:

Different types of composites are invent to achieve our desire material properties, linked with modern material system associated with industries, like cermets, cemented carbides.

Reinforcement: fibers

GlassCarbonOrganicBoronCeramicMetallic

Matrix materials

PolymersMetalsCeramics

Interface

Bonding surface

Components of composite materials

HOW TO FORM COMPOSITES?There are two phases.

Matrix (primary phase) Reinforcement phase (secondary phases).

• The reinforcement is stronger and stiffer, forming a sort of backbone, while

• The matrix keeps the reinforcement in a set place. The binder also protects the

reinforcement, which may be brittle or breakable.

EXAMPLE: Humans have been creating composite materials to build stronger and

lighter objects for thousands of years. The most primitive composite materials comprised straw and mud in the form of

bricks for building construction. Mud is an excellent binding material, but it cannot stand up to compression and force well. Straw, on the other hand, is well able to withstand compression without crumbling or breaking, and so it serves to reinforce the binding action of the mud.

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Metal Ceramic Polymer

Metal Powder metallurgy parts – combining immiscible metals

Cermets (ceramic-metal composite)

Brake pads

Ceramic Cermets, TiC, TiCNCemented carbides – used in toolsFiber-reinforced metals

SiC reinforced Al2O3 Tool materials

Fiberglass

Polymer     Kevlar fibers in an epoxy matrix

Elemental (Carbon, Boron, etc.)

Fiber reinforced metalsAuto partsaerospace

  Rubber with carbon (tires)Boron, Carbon reinforced plastics

MMC’s CMC’s PMC’sMetal Matrix Composites Ceramic Matrix Comp’s. Polymer Matrix Comp’s

Primary phase, matrixSecondary phase ,reinforcement

Metal Matrix Composites (MMCs) Include mixtures of ceramics and metals, such as cemented carbides

and other cermets, as well as aluminum or magnesium reinforced by strong, high stiffness fibers

Ceramic Matrix Composites (CMCs) Least common composite matrix. Aluminum oxid and silicon carbide

are materials that can be imbedded with fibers for improved properties, especially in high temperature applications

Polymer Matrix Composites (PMCs) Thermosetting resins are the most widely used polymers in PMCs.

Epoxy and polyester are commonly mixed with fiber reinforcement.

Classification of composite material

METAL MATRIX COMPOSITES A metal matrix composite (MMC) is

composite material with at least two constituent parts, one being a metal. The other material may be a different metal or another material, such as a ceramic or organic compound. When at least three materials are present, it is called a hybrid composite. An MMC is complementary to a cermet.

Cemented carbides are composed of one or more

Carbide compounds bonded in a metallic matrix

Common cemented carbides are based on: Tungsten carbide (WC) Titanium carbide (TiC) Chromium carbide (Cr3C2) Tantalum carbide (TaC)

Carbide ceramics constitute the principal ingredient in cemented carbides, typically ranging in content from 80% to 95% of total weight.

Principle metallic binders are: Cobalt – used for WC Nickel - used TiC and Cr3C2

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METAL MATRIX COMPOSITES

Processing of MMC’s

Solid state method. Liquid state method. Physical vapour deposition. Insitue fabrication technique.

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Manufacturing and forming methodsSolid state methods: Powder blending and consolidation (powder metallurgy): Powdered metal and

discontinuous reinforcement are mixed and then bonded through a process of compaction, degassing, and thermo-mechanical treatment (possibly via hot isostatic pressing (HIP) or extrusion).

Foil diffusion bonding: Layers of metal foil are sandwiched with long fibers, and then pressed through to form a matrix.

Liquid state methods: Electroplating / Electroforming: A solution containing metal ions loaded with reinforcing

particles is co-deposited forming a composite material. Stir casting: Discontinuous reinforcement is stirred into molten metal, which is allowed to

solidify. Squeeze casting: Molten metal is injected into a form with fibers preplaced inside it. Spray deposition: Molten metal is sprayed onto a continuous fiber substrate. Reactive processing: A chemical reaction occurs, with one of the reactants forming the

matrix and the other the reinforcement.

Manufacturing and forming methodsVapor deposition: Physical vapor deposition: The fiber is passed through a thick cloud of vaporized metal,

coating it.

In situ fabrication technique: Controlled unidirectional solidification of a eutectic alloy can result in a two-phase

microstructure with one of the phases, present in lamellar or fiber form, distributed in the matrix.

USES OF MMC:Due to hardness and high wear resistance we

can use metal matrix (cemented carbide) composites for tooling in different manufacturing processes

• Carbide cutting tools.• Cemented carbide is used for wire drawing dies.• Rock drilling bits and other mining tools.• Dies for powder mettalurgy.

Due to high temperature applications titanium carbide have a following uses.

• It is used in gas turbine nozzle vanes.• Used for valve seats, thermocouple protection tubes.• Hot working spinning tools.

Most important uses of metal matrix composites are in aircrafts and because of high strenght-to-weight ratio, and due to high temperature strenght properties and good electrical and thermal conductivity they are mostly used in turbine machinery.

USES OF MMC:

Cemented carbide tools

Rock drilling bits and tips

Ceramic Matrix Composite (CMC)

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Ceramic Matrix composites

Ceramic matrix composites (CMC) are used in applications where resistance to high temperature and corrosive environment is desired. CMCs are strong and stiff but they lack toughness (ductility)

Matrix materials are usually silicon carbide, silicon nitride and aluminum oxide, and mullite (compound of aluminum, silicon and oxygen). They retain their strength up to 3000 oF.

Fiber materials used commonly are carbon and aluminum oxide.

Applications are in jet and automobile engines, deep-see mining, cutting tools, dies and pressure vessels.

PROPERTIES OF CMC ADVANTAGES: High stiffness, hardness, hot hadness. Compressive strenght. Low density.

DISADVANTAGES: Low toughness. Bulk tensile strength. Thermal cracking.

TECHICAL DIFFICULTIES: Difficulties including thermal and chemical compatibility of the

constituents in the CMC, during proccessing and also limting ceramic material used.

MATERIALS FOR CMC.

PRIMARY PHASE MATERIALS(MATRIX)

Alumina. Boron nitride. Boron carbide. Titanium carbide. Silicon carbide. Silicon nitride.

SECONDRY PHASE MATERIALS(REINFORCING AGENT)

Short fibers such as whiskers. Long fibers used in particular

processing methods.

Purpose of using CMC Increase the toughness

PROCCESSING OF CMS Formation of raw material.

Crushing. Grinding.

Shaping proccess. slip casting. Platic forming. Semi dry pressing. Dry pressing.

Drying. Firing. Finishing.

SHAPING PROCCESS.

PLASTIC FORMING

Slip casting

SEMI-DRY PRESSING

Dry pressing

DRYING

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Application of Composites

Pedestrian bridge in Denmark, 130 feet long

(1997)

Swedish Navy, Stealth (2005)

Lance Armstrong’s 2-lb. Trek bike, 2004 Tour de France

Pedestrian bridge in Denmark, 130 feet long

(1997)

Lance Armstrong’s 2-lb. Trek bike, 2004 Tour de France

Due to weight-to-strength and weight-to-stiffness ratio we can use it in airplane

Conclusion:There is so many categories of engineering materials are

using in the whole world and further advancements and modifications are happening in that all. After examine our environments and world resources further we have to compete for the materials that are able to be

Recycled again and again. Having good engineering properties. Easily available.

and so many like this.

Lecture-05: Sheet Metal Forming Processes 34/39

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