can also be classified in two direct and indirect squeeze casting methods. In the
direct squeeze casting setup, the die is part of the mold and the pressure is
directly applied into the melt to penetrate the reinforcement perform. In contrast, the indirect squeeze casting
setup has gate system which is used to apply pressure into the melt for the
infiltrations of the reinforcement perform. Figure 2.4 shows the direct and
indirect squeeze casting processes (Park S. J., & Seo M. K., 2011;
Dhanashekar M., 2014).
major advantages of the squeeze casting process are listed below (Yilmaz H. S.,
2004; Dhanashekar M., 2014; Alhashmy A., 2012):
Gas porosity or shrinkage porosity are minimized/eliminated
in the developed composites.
Feeders or risers are not required, so no metal wastage
Alloy fluidity (castability) is not critical since
alloys can be squeeze cast to finished shape by pressure.
Improved mechanical properties i.e high strength to
weight ratio, better wear & corrosion resistance, higher hardness,
better resistance to high temperatures, improved fatigue and creep
Figure 2.3 Standard squeeze casting process for
fabricating AMMC (Vijayaram T. et al., 2006; Shalu T. et al., 2009; Alhashmy A.,
Figure 2.4 (a) Direct squeeze casting. (b) Indirect
Squeeze Casting. (Park S. J., & Seo M. K., 2011).
Two Phase (Solid-Liquid)
Two phase (solid-liquid) processes involve
mixing of ceramic and matrix in a region of the phase diagram where the matrix
contains both solid and liquid phases. Osprey deposition, rheocasting and variable
co-deposition of multiphase materials are some of the processing methods under
this category (Yilmaz H. S., 2004; Kandpal B. C. et al, 2014).
Deposition techniques processes involve
coating individual fibers in a tow with the matrix material needed to form the
composite followed by diffusion bonding to form a consolidated composite plate
or structural shape. However, it is time consuming process. There are several
Deposition techniques are available such as immersion plating, electroplating, spray
deposition, chemical vapor deposition (CVD), physical vapor deposition (PVD)
and spray forming (B. C. Kandpal et al, 2014).
In situ processes
In this processes the reinforcement
phase is formed in one step in the matrix as a result of precipitation of the
melt during cooling and solidification (Kandpal B. C. et al, 2014).
Aluminum Metal Matrix
Composite Reinforced with Silicon Carbide Particles (Al-SiCp)
SiCp are one of the most used types of
reinforcement to reinforce Aluminum (Al) alloy in order to produce composite
materials that have the desired properties. SiC enhances the tensile strength,
hardness, density and wear resistance of Al alloy (Murty S. V. S. N. et al.,
2003; Iqbal A. A.; 2016).
T. Ozben (2008) found that the increase
in the ratio of SiCp in Al-SiCp composites enhance the tensile strength,
hardness and density whereas the impact toughness decreased. In addition, particles
clustering, particle cracking and weak matrix-reinforcement bonding are the
factors affecting the impact behavior of SiC (Ozden S. et al., 2007; Iqbal A.
P. Zhang and L. Fuguo (2010) studied the
impact of reinforcement particles agglomeration on the flow behavior of SiCp
reinforced AMMCs. They concluded that the particle agglomeration has greater
effects on the mechanical response of the matrix during the tensile deformation
compared to the elastic response. They also revealed that the agglomeration
region has higher number of fractured particles compared to the particle random
distribution region (Zhang P., & Fuguo L., 2010; Iqbal A. A.; 2016).
K. L. Meena et al. (2013) have studied
the impact of SiCp volume in the Al-SiCp composites. The study used 5%, 10%,
15% and 20% by weight of SiC to investigate tensile strength, hardness, density
and impact strength. In addition the study found that all of these properties
increase with the increase in the weight percentage of SiCp.
Furthermore, Srinivasa K. et al. (2014) fabricate
Al LM6-SiCp composites using stir casting method. They fabricated Al LM-6-SiCp
with varying composition of 0%, 5%, 10% and 15% by weight of SiC. They
concluded that as the ratio of SiC content increase the hardness of Al LM6-SiCp
composite increases. However the wear resistance decreases gradually with the
increase of SiC content.
addition, N. S. Kalyankar et al. (2016) did a study that was focusing on the
change in the mechanical properties of Al LM25-SiCp composites and fabricated
by stir casting method. Al LM25 matrix material was reinforced with 10%, 15%
and 20% by weight of SiC. They found that wear resistance of the fabricated
composite increased with increasing SiC weight percentage and hardness
decreased with SiC content. Also they concluded that the tensile strength,
yield strength and percentage of elongation increased with the increase in the
weight percentage of SiC.
and interface de-bonding (Iqbal A. A. et al., 2003; Iqbal A. A. et al., 2004).
G.G. Hosamani et al. (2016) investigated
the wear characteristics, microstructure and the
Different studies have been conducted to study and
understand the fatigue and fracture behavior of Al-SiCp composites. A. A. Iqbal
et al. found in two separate studies on the hybrid AMMCs that the particle-matrix
interface is the place where the fatigue damage initiates. They also concluded
that the fatigue damage propagates by the particle fracture
mechanical properties of SiC reinforced AMMCs. They
fabricated AMMCs with 0, 3, and 7 weight % of SiC content by stir casting
process. They experimentally concluded that the addition of SiC reinforcements
in Al matrix increased wear resistance, tensile strength and compressive
strength. The maximum weight percentage of SiC reinforcement at which the
fabricated AMMCs showed maximum wear resistance, tensile strength and
compressive strength was 7%. They also found from the microstructure analysis
that clustering and non-homogeneous distribution of SiC particles. They
attributed this to the improper time given for contact between SiC particle and
Al matrix and the poor wetting of SiC particle in molten Al.