This document presents an overview of metal matrix composites (MMCs). It defines MMCs as composites with at least two constituent parts, one being a metal matrix and the other being another material like another metal, ceramic, or organic compound. The document discusses the composition, production, properties and applications of MMCs. It notes that MMCs combine properties like high strength and stiffness with lower density compared to unreinforced metals. Common reinforcement materials in MMCs include fibers of boron, silicon carbide, and alumina. The document outlines some important MMC systems and their advantages like higher temperature capability and strengths, as well as disadvantages like higher cost. Applications discussed include automotive and aerospace parts.

1. Maulana Azad National Institute of
Technology
Metal matrix composite(MMCs)
Presented by
Chandan Prasad
Scholar no-162119117
Presented to
Material science and metallurgical
department

2. CONTENTS
 INTRODUCTION
 CLASSIFICATION OF METAL MATRIX COMPOSITE
 METAL MATRIX COMPOSITES (MMCs)
 COMPOSITION
 MATRIX..
 REINFORCEMENT
 PRODUCTION AND PROCESSING OF METAL MATRIX COMPOSITES
 POSSIBLE APPLICATIONS OF METAL MATRIX COMPOSITES
 METAL MATRIX COMPOSITES FOR SPACE APPLICATION
 THE MOST IMPORTANT MMC SYSTEMS
 ADVANTAGES OF MMCs
 DISADVANTAGES OF MMCs

3. INTRODUCTION
 Conventional monolithic materials have limitations in
achieving good combination of strength, stiffness,
toughness and density.
 To overcome these shortcomings and to meet the ever
increasing demand of modern day technology,
composites are most promising materials of recent
interest.
 Metal matrix composites (MMCs) possess significantly
improved properties including high specific strength;
specific modulus, damping capacity and good wear
resistance compared to unreinforced alloys.

4. CLASSIFICATION OF METAL MATRIX COMPOSITE

5. METAL MATRIX COMPOSITES (MMCs)
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.

6. COMPOSITION
MMCs are made by dispersing a reinforcing
material into a metal matrix. The
reinforcement surface can be coated to
prevent a chemical reaction with the matrix.
For example, carbon fibers are commonly
used in aluminum matrix to synthesize
composites showing low density and high
strength.

7. MATRIX
The matrix is the monolithic material into which
the reinforcement is embedded, and is
completely continuous.
This means that there is a path through the
matrix to any point in the material, unlike two
materials sandwiched together.
The matrix is usually a lighter metal such as
aluminum, magnesium, or titanium, and provides
a compliant support for the reinforcement.

8. REINFORCEMENT
The reinforcement material is embedded into
the matrix.
It is used to change physical properties such as
wear resistance, friction coefficient, or
thermal conductivity.
The reinforcement can be either continuous,
or discontinuous.

9. The following demands are generally applicable:
 Low density,
 Mechanical compatibility (a thermal expansion coefficient
which is low but Chemical compatibility,
 Thermal stability,
 High Young’s modulus,
 High compression and tensile strength,
 Good process ability,
 Economic efficiency.

10. PRODUCTION AND PROCESSING OF METAL
MATRIX COMPOSITES

11. DIRECT AND INDIRECT SQUEEZE
CASTINGS

12. Fabrication Method
Fabrication methods for MMCs are varied. One method
of manufacturing them is diffusion bonding which is
used in manufacturing boron/aluminum composite
parts. A fiber mat of boron is placed between two thin
aluminum foils about 0.05 mm thick. A polymer binder
or an acrylic adhesive holds the fibers together in the
mat. Layers of these metal foils are stacked at angles as
required by the design. The laminate is first heated in a
vacuum bag to remove the binder. The laminate is then
hot pressed with a temperature of about 500°C and
pressure of about 35 MPa in a die to form the required
machine element.

14. MECHANICAL PROPERTIES OF MMCs
 lower coefficient of thermal and electrical
conductivity

15. STRENGTH OF MMCs

16. Young’s Modulus of MMCs

17. APPLICATIONS
1. Driver shaft for people and light load motor vehicles
Materials: AlMg1SiCu+ 20 vol % Al2O3P
Processing: Extrusion from cast feed material
Development aims--- high dynamic stability , high Young’s Modulus ( 95 GPa)
---low density (2.95 gm cm-3)
--- high fatigue strength (120 MPa)
--- sufficient toughness (21.5 MPa)
--- substitution of steel
2. Vented passenger car disc
3. Disc brake caliper for passenger car
4. Aerospace space industry also uses MMCs
5. Military defence

18. Fig: Partial short fibers reinforced light metal diesel pistons.
Fig: Cast brake disk particle of reinforced aluminum.

19. Fig: Drive shaft particle of reinforced aluminum for passenger cars .
Fig: Disk brake caliper for passenger cars of conventional cast-iron (left) and
an aluminum matrix composite material (AMC)

20. METAL MATRIX COMPOSITES FOR SPACE
APPLICATION
Figure:12Mid-fuselage structure
of Space Shuttle Orbiter showing
boron-aluminum tubes
Figure: Al high-gain antenna wave guides/
boom for the Hubble Space
Telescope (HST) shown (a-left) before
integration in the HST, and (b-right) on the
HST as it is deployed in low-earth orbit
from the space shuttle orbiter

21. Material application in aerospace

22. Features of composite in aerospace

23. Prospects of composite material
To look over financial and performance
benefits during offshore operations.
To decrease maintenance costs.
To enable operations that otherwise are not
feasible both technically and financially

24. Challenges in composites
 Current composite material models within
commercial design software require very long
solution times.
 For composites to be properly evaluated at these
early stages, the automotive industry needs a factor
of ten reductions in solution times which is yet not
been solved.
 Manufacturing is an issue for composites.
 Defects analysis

25. THE MOST IMPORTANT MMC SYSTEMS
 Aluminum matrix
 Continuous fibers: boron, silicon carbide, alumina, graphite
 Discontinuous fibers: alumina, alumina-silica
 Whiskers: silicon carbide
 Particulates: silicon carbide, boron carbide
 Magnesium matrix
 Continuous fibers: graphite, alumina
 Whiskers: silicon carbide
 Particulates: titanium carbide
 Copper matrix

26. THE ADVANTAGES OF MMCs
Higher temperature capability
 Fire resistance
 Higher transverse stiffness and strength
No moisture absorption
 Higher electrical and thermal conductivities
 Better radiation resistance

27. THE DISADVANTAGES OF MMCs
Higher cost of some material systems .
Relatively immature technology .
Complex fabrication methods for fiber-reinforced
systems (except for casting).

28. CONCLUSION
 Metal matrix composites offer sufficient promise and have reached
the degree of maturity that indicates an expansion of their use. To
realize their full potential however these composites deserve
greater attention and support.
 The numbers of MMCs currently are in various stages of
development: these are boron/aluminum, beryllium/titanium, and
boron/titanium, graphite/aluminum, and supper alloys reinforced
with refractory metal.
 The boron/reinforced aluminum system is in most advanced stage
of development and properly data for this system are sufficient for
design in structural application.

29. THANK YOU