1. Review on Fabrication Methods of in situ Metal Matrix Composites
By:
1. Law Mei Lin B BMFB1
2. Mohd Aqhairi Bin Bahari B BMFB2
3. Mohamad Izzudin Bin Abdul Hamid B BMFB1
4. Noor Ayuhaan Binti Abd Lah B BMFB1
5. Rianah binti Jiren B BMFB2
6. Siti Sainillah Binti Sulaiman B BMFB1
7. Nadiah Binti Jaafar B BMFB1

2. In situ is a Latin phrase which translates literally to 'In position'.
What is In Situ?
In situ is a Latin phrase which translates literally to 'In position'.

3. 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.

4. Advantages of in situ techniques
There is thermodynamic compatibility at the matrix-reinforcement interface.
2. Also, the reinforcement surfaces are likely to be free of contamination.
~ Therefore, stronger matrix dispersion bond can be achieved.

5. Technologies Powder Metallurgy Method (Fabrication of in situ Fe/TiC)
Liquid-Gas Reaction
(Fabrication AlN/Al composite)
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

6. 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:
Simplicity
Economy
Flexibility

7. In situ – Processed by Ingot Metallurgy
Tong and Fang (1998) fabricated Al-TiC composites:
with refined microstructure,
enhanced dispersion hardening of the reinforcing phases

8. Process

9. Ingot Metallurgy (Synthesis of composites)
Al (99.9%) Ti (99.7%)
Graphite powder (40-50 μm)
Melt in
graphite-lined induction furnace with argon gas flow.
Heated
1100 °C – 1200°C 1h
1300 °C – 1400°C
10 minutes
Mixture direct chill cast into ingot bars

10. Example of Ingot Metallurgy
Diagram
This system is now less expensive to produce in situ composite with titanium matrix and generally discontinuously reinforced MMCs, leading, among other things, produce a wealth of different materials.
Example of Ingot Metallurgy

11. 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
-Function of this process to produce ribbon shape
-Chill block melt spinning is a rapid quenching process in which a jet of molten metal is directed onto a cold moving surface, such as a spinning disk, where the jet is shaped and solidified; quench rates are 1000 to 1,000,000 K per second.

12. Video (chill block melt spinning)
Ribbon shape

13. Chemical Analysis
The analysis of master ingots was done by the wet method.
Carbon was determined by using automatic combustion apparatus.
Sample is combusted in a stream of oxygen and the carbon of specimen is converted into CO2.
The CO2 is fed into a measuring chamber where the concentration peak is detected with nondispersive spectrometer.
The linear signal is integrated and displaced digitally after weight compensation and blank correction.

14. AUTOMATIC COMBUSTION APPARATUS
Stream of oxygen
Chamber
Detection with a nondispersive spectrometer

15. Applications

16. MMC by IN SITU FABRICATION METHOD
As a general….
MMC by IN SITU FABRICATION METHOD
. Short-fiber reinforced in situ MMC
. Long-fiber reinforced in situ MMC
. Particulate in situ MMC

17. IN SITU MMC APPLICATIONS
Rapid Solidification Process
Ex : TiC particulate-reinforced 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

18. 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).

19. Q & A

20. 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.

21. 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.

22. 3. Why the particulate reinforced MMCs are more
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.

23. 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:
It can be achieved in a short processing time
Many kinds of ceramic powder can be put into alloy liquid