Hh

1. M.Tech. Research Project:
 Fabrication and Analysis of Aluminium Metal Matrix Composites(LM25Al-SiCp)
Presentation on 2nd May, 2013
Under the Guidance of
Dr.B. Anand Ronald
Assoc.Prof. Mechanical Engineering
SSN College of Engineering
Chennai

2.  Introduction: Composites
 Properties of Composites
 Applications of Composites
 Applications of Magnesium Matrix Composites (MMC)
 Literature Review
 Current Status- Magnesium Based Composite Materials
 Processing Techniques
 Synthesis and Characterization of MMC Using Stir Casting
 Proposed Research Work
Presentation on 2nd May, 2013

3.  Composite materials are materials made from two or more constituent
materials with significantly different physical or chemical properties, that
when combined, produce a material with characteristics different from the
individual components.
 The individual components remain separate and distinct within the finished
structure.
 Composite materials are said to have two phases. The reinforcing phase is
the fibers, sheets, or particles that are embedded in the matrix phase
 Composite materials can take many forms but they can be separated into
three categories based on the strengthening mechanism. These categories
are dispersion strengthened, particle reinforced and fiber reinforced.
 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
 Suitability for automatic processing has made the particulate-reinforced
composite preferable to the fiber-reinforced composite for automotive
applications
Presentation on 2nd May, 2013

4. Presentation on 2nd May, 2013
 Reinforcing materials are strong with low densities while the matrix is usually a
ductile, or tough, material.
 Dispersion strengthened composites have a fine distribution of secondary
particles in the matrix of the material. These particles impede the mechanisms
like dislocation movement and slip which allow a material to deform.
 The composite combines the strength of the reinforcement with the toughness
of the matrix to achieve a combination of desirable properties not available in
any single conventional material.
 Composites also offer the advantage of being tailorable, so that properties, such
as strength and stiffness, can easily be changed by changing amount or
orientation of the reinforcement material.
 In comparison with conventional magnesium alloys Magnesium Metal Matrix
Composites having high load bearing capacity, low casting defect and high
thermal stability and mechanical properties like hardness, tensile strength, etc..

5. Presentation on 2nd May, 2013
 Composite materials are generally used for buildings, bridges and
structures, boat hulls, race car bodies, shower stalls, bathtubs, and
storage tanks, imitation granite and cultured marble sinks and countertops
 Magnesium based metal matrix composites are used various applications
in automotive industry
 Fiber reinforced composite materials are used in high mechanical load
bearing applications
 Used for manufacturing structural components for Aerospace applications
 Used for fabricating Ceiling panels, Plumbing components, Pressure
Vessels, etc…

6. Presentation on 2nd May, 2013
• The potential applications of magnesium matrix composites are in the
automotive industry include their use in:-
 Disk rotors, piston ring grooves
 Gearbox bearings
 Fabrication of connecting rods
 Fabrication of shift forks
 Valve covers, clutch housing, steering column, cam covers, brackets,
seat frames, instrument panels, clutch piston, blade stators and
crank cases of air-cooled automotive engines
• Suitable for lightweight and high performance materials application like
aerospace and automotive industry

7. Presentation on 2nd May, 2013
• Journal of Materials Science, Hai ZHI YE,Xing Yang Liu, 39(2004)6153-6171
• Engineering Composite Materials, Bryan Harris,1999
• Journal of Materials Science, W.L.E.Wong,M.Gupta 40(2005)2875-2882
• Development of Nano-composites Based on Magnesium Alloy System AZ31B, Nguyen
Quy Bau,2009
• Metallography, M.H.Richman, A.P.Levitt and E.S.Dicesare, 6(1973)497-510
• Nanostructural Characterization of Ternary Carbides in Carbon-Fibre Reinforced Mg-Al
Matrices and Their Influence on The Composite Properties, A.Feldoff, E.Pippel,
J.Woltersdorf, Max-Planck-Institute for Microstructural Physics, Weinberg 2, D-06120
Halle, Germany
• Polymer, D.R. Paul, L.M. Robeson, 49 (2008) 3187–3204
• Polymer, U. Hippi, J. Mattila, M. Korhonen, J. Seppala, 44 (2003) 1193–1201
• Materials Research Bulletin, S.F.Hassan, M.Gupta, 37(2002) 377-389
• Biomaterials, F. Witte et al. ,28 (2007) 2163–2174
• Surface & Coatings Technology, A. Mandelli et al., 205 (2011) 4459–4465

8. Presentation on 2nd May, 2013
 Magnesium alloys have been increasingly used in the automotive industry due to
their lightweight.
 The density of magnesium is approximately two thirds of that of aluminum, one
quarter of zinc, and one fifth of steel.
 Magnesium alloys offer a very high specific strength among conventional
engineering alloys.
 In addition, magnesium alloys possess good damping capacity excellent
castability, and superior machinability.
 Issues
 Compared to other structural metals, magnesium alloys have a relatively low
absolute strength, especially at elevated temperatures.
 Currently, the most widely used magnesium alloys are based on the Mg-Al
system. Applications of Mg-Al alloys are usually limited to temperatures of up to
120◦c.

9. Presentation on 2nd May, 2013
• Stir Casting
• Squeeze Casting
• Powder Metallurgy
Method Working
range
Metal yield Reinforcement
fraction
( vol %)
Damage to
reinforcement
Fabrication
cost
Stir Casting
Wide range of
shape, larger
size(up to 500
kg
Very high,
>90%
~30 No damage Least
expensive
Squeeze
Casting
Limited by
preform
shape,(up to
2 cm height)
Low ~45 Severe damage Moderately
expensive
Powder
Metallurgy
Wide range,
restricted size High - Fracture Expensive

10. Presentation on 2nd May, 2013
• Squeeze Casting
 The reinforcement (either powders or fibers/whiskers) is usually made into
a preform and placed into a casting mold.
 The molten magnesium alloy is then poured into the mold and solidified
under high pressure.
 Excessively high pressure may produce a turbulent flow of molten
magnesium, causing gas entrapment and magnesium oxidation
 It also damage the reinforcement in a composite material and reduce the
mechanical properties of the composites
 The shortcomings of the squeeze casting process lie mainly in the
constraints on the processing imposed by the casting shape, its
dimensions and its low suitability for large quantity automatic production.

11. Presentation on 2nd May, 2013
• Powder Metallurgy
 In the powder metallurgical process, magnesium and reinforcement
powders are mixed, pressed, degased and sintered at a certain
temperature under a controlled atmosphere or in a vacuum
 This method requires alloy powders that are generally more expensive
than bulk material
 This method involves complicated processes including degasing and
sintering at high temperature during the material fabrication.
 Due to this powder metallurgy may not be an ideal processing technique
for mass production

12. Presentation on 2nd May, 2013
 Reinforcing phases (usually in powder form) are distributed into molten
magnesium by mechanical stirring
 The major merit of stir casting is its applicability to large quantity
production.
 Among all the well-established metal matrix composite fabrication
methods, stir casting is the most economical (Compared to other
methods, stir casting costs as little as one third to one tenth for mass
production
 For the above reason, stir casting is currently the most popular
commercial method of producing metal based composites.
 Due to this reason we are proposing to use stir casting method for
production of magnesium metal matrix composites.

13. Presentation on 2nd May, 2013

14. Presentation on 2nd May, 2013
Molten Magnesium Metal
Graphite
Particulates

15. • Enhancement of Mechanical properties of Magnesium
composites using Graphite reinforcement and intrusion of
similar particulates( SiCP , TiC etc….)
• To homogenously distribute the reinforcement phases to
achieve a defect-free microstructure
• Fabrication of MMCs using stir casting method
• Investigating the Mechanical Properties including
 Tensile Strength
 Young’s Modulus
 Hardness
Presentation on 2nd May, 2013

16. • Improving Machining properties
• Enhancement in Casting properties
• Tribological Analysis of conventional and Magnesium MMC
• Microstructural Analysis Using
 SEM,EPMA and AFM Techniques
• Structural Analysis Using
 X-Ray Diffraction Technique
Presentation on 2nd May, 2013

17. THANK YOU
Presentation on 2nd May, 2013

18. X-ray Diffraction Technique
• To study the crystal structure using X-Ray
• A diffraction pattern is obtained during XRD analysis called diffractogram
• Due to the virtue of uniform lattice spacing an interference pattern is
produced
• Due to the crystal in the atomic planes act on the X-Rays
• Interference pattern is specific to each substance and gives information
about the structure of grains(made up of atoms or molecules) in the
crystal
Presentation on 2nd May, 2013