Review on Fabrication
Methods of in situ
Metal Matrix Composites
By:
1.
2.
3.
4.
5.
6.
7.
LAW MEI LIN
MOHD AQHAIRI BIN BAHARI
MOHAMAD IZZUDIN BIN ABDUL HAMID
NOOR AYUHAAN BINTI ABD LAH
RIANAH BINTI JIREN
SITI SAINILLAH BINTI SULAIMAN
NADIAH BINTI JAAFAR
B050810007
B050810175
B050810048
B050910310
B050910060
B050910279
B050910296
4BMFB1
4BMFB2
4BMFB1
4BMFB1
4BMFB2
4BMFB1
4BMFB1
1
What is In Situ?
In situ is a Latin phrase which translates
literally to 'In position'.
2
What is in situ techniques?
Involve a chemical reaction resulting in the
formation of a very fine and
thermodynamically stable reinforcing
ceramic phase within a metal matrix.
3
Advantages of in situ techniques
1. There is thermodynamic compatibility at
the matrix-reinforcement interface.
2. Also, the reinforcement surfaces are
likely to be free of contamination.
~ Therefore, stronger matrixdispersion bond can be achieved.
4
Technologies
1. Powder Metallurgy Method
(Fabrication of in situ Fe/TiC)
2. Liquid-Gas Reaction
(Fabrication AlN/Al composite)
3. Solid-Gas-Liquid Reaction Method
(Formation of fine single crystal TiC platelets in
the Al based matrix )
4. In situ – Processed by Ingot Metallurgy
(Fabrication of Al-TiC composites)
5. Plasma Metallurgy Method
5
In situ – Processed by Ingot
Metallurgy
What it means?
in which the solidification process where the
reinforcing particles are formed in situ in the
molten alloy.
Attractiveness:
1.Simplicity
2.Economy
3.Flexibility
6
In situ – Processed by Ingot
Metallurgy
1. Tong and Fang (1998) fabricated Al-TiC
composites:
•
•
with refined microstructure,
enhanced dispersion hardening of the
reinforcing phases
7
Process
8
Ingot Metallurgy
(Synthesis of composites)
Al (99.9%) +
Ti (99.7%)
Graphite powder
(40-50 μm)
Heated
1100 °C – 1200°C
1h
Melt in
graphite-lined
induction
furnace with
argon gas flow.
1300 °C – 1400°C
10 minutes
Mixture direct chill
cast into ingot bars
9
Diagram
Example of Ingot Metallurgy
10
Rapid solidification
(by chill block melt spinning)
20g of master material was contained in a crucible
Heated using high frequency induction
When the temperature achieve at 1350 °C, and hold for 5 minutes
Melt was ejected to the surface copper rotating wheel by using
argon gas
The wheel rotating with a surface velocity (30m/min) (solidify
process)
The resultant ribbon form
11
Video
(chill block melt spinning)
Ribbon shape
12
Chemical Analysis
• The analysis of master ingots was done by the
wet method.
• Carbon was determined by using automatic
combustion apparatus.
1. Sample is combusted in a stream of oxygen and the
carbon of specimen is converted into CO2.
2. The CO2 is fed into a measuring chamber where the
concentration peak is detected with nondispersive
spectrometer.
3. The linear signal is integrated and displaced digitally
after weight compensation and blank correction.
13
AUTOMATIC COMBUSTION
APPARATUS
Stream
of
oxygen
Chamber
Detection
with a
nondispersive
spectrometer
14
Applications
15
As a general….
. Short-fiber
reinforced in
situ MMC
MMC by IN
SITU
FABRICATION
METHOD
. Particulate
in situ MMC
. Long-fiber
reinforced
in situ MMC
16
Rapid Solidification
Process
Ex : TiC particulatereinforced Al
Vapor phase Infiltration
Ex : Silica base
aerogel/transition metal
composite
IN SITU MMC
APPLICATIONS
Controlled crystallization
Ex : magnetic device such
as choke coils &
transfomers
17
APPLICATIONS OF IN SITU
1) Aerospace
In the aerospace industry, equipment on-board aircraft must be tested in situ,
or in place, to confirm everything functions properly as a system
2) Petroleum production
In situ refers to recovery techniques which apply heat or solvents to heavy oil
or bitumen reservoirs beneath the earth's crust.
3) Experimental Physics
In situ refers to a method of data collection or manipulation of a sample without
exposure to an external environment.
4) Biology
In situ means to examine the phenomenon exactly in place where it occurs (i.e.
without moving it to some special medium).
Additional
Information
19
In-Situ Polymerization
• In-situ polymerization has been used to prepare
nanocomposites.
• Inorganic nano-particles are dispersed in monomer,
followed by heat or other treatment of the reaction
mixture to induce polymerization.
• Advantages of in-situ polymerization technique:
1. Uniform CNT dispersion in monomers
2. Polymer chains grafted onto the convex walls of
carbon nanotubes during in-situ; thus CNT
homogeneously dispersed in polymer matrix.
20
• Advantages: (cont.)
3. Important for the preparation of insoluble and
thermally unstable polymer composites, which cannot
be processed by solution or melt processing.
4. For preparation of polymer composites with high
nanotube loading, in-situ provides very good miscibility
with almost any types of polymers.
21
In-Situ Polymerization
Processing
• In-situ polymerization methods used to fabricate CNTPMMA composites by incorporating CNTs during the
course of polymerization of MMA.
• Basic starting materials:
1. Nanotubes
2. MMA monomer
• Method: In-situ free radical polymerization method
involves polymerization of monomer using a radical
initiator such as 2.2´-azobisisobutyronitrile (AIBN).
• CNTs are dispersed through ultrasonication in the
prepolymer.
22
• Adding CNT at prepolymer provides good dispersion in
the low viscosity of the prepolymer.
• As the polymerization progresses, the viscosity of the
solution increases and the polymer grows and wraps
around the dispersed CNTs.
• Benefits:
a) Higher interfacial strengths as CNTs interact with the
growing polymer, thus forming stronger CNT-polymer
bonds via non-covalent or covalent interactions.
b) Composites with enhanced mechanical, electrical
and tribological were obtained.
23
• For another research of MWCNT-PMMA composites
synthesized by in-situ bulk polymerization usig AIBN
as free radical initiator, the microstructure are shown in
Figure A below.
Figure A: Microstructure of the in-situ facricated MWCNT-PMMA composite.
The bright masses indicates CNTs wrapped with PMMA layers
24
Q&A
25
1. What is the criteria for
reinforcement selection?
In general, There are necessary criteria or conditions that
must be satisfied for the selection of a ceramic as
reinforcement in the manufacture of good and standard
metal matrix composites.
Such criteria include density, melting temperature, size
and shape, elastic modulus, tensile strength, thermal
stability, compatibility with matrix material, coefficient of
thermal expansion, and cost.
2. Why choose Ti and Al for the In-situ
processed by Ingot metallurgy?
In general, selection of metal or its alloy as matrix for
production of MMC depends on the type, required
properties and the kind of application where such
composite is required.
From this experiment, Al based and Ti based metal matrix
composites have a high potential for advanced structural
applications when high specific strength as well as good
elevated temperature resistance.
3. Why the particulate reinforced MMCs are more
interesting due to their ease of fabrication, low costs,
and isotropic properties?
Answer : The properties of MMCs are controlled by the size
and volume fraction of the reinforcement phase as well by
the nature of the matrix reinforcement interface
4. In traditional MMCs, wetting between molten metal and
reinforcements is often poor. How this problem can be
treated?
Answer : This problem can be treated through a strongly
reactive alloying addition, such as Mg and Li and through
reinforcement coating.
5) How do we know if MMC is a hybrid composite?
6) What do you have in mind about in situ hybrid composite?
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.
Scientist do hybrid to pick up good qualities. So there are 2 things better in
something they try to mix and make a best item. For e.g. some flower have
good looks but no smell and other have great smell but dull look so they
mix and try to make a flower with great look and smell together.
The authors suggest that it may name as in situ hybrid composite because:
1) It can be achieved in a short processing time
2) Many kinds of ceramic powder can be put into alloy liquid