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S. Mozammil et al.
performance-critical end products due essentially because of their high strength
to weight ratio [σ /ρ], excellent wear resistance, adequate fatigue resistance, and
importantly overall good thermodynamic stability [1–3]. Mechanical properties of
the aluminum alloy-based metal matrix composites [denoted as AMCs] are significantly influenced by the conjoint and mutually interactive influences of matrixreinforcement bonding and the fabrication and processing route chosen and used to
process the composite material. Ceramic reinforcement particles, such as titanium
diboride (TiB 2 ), aluminum oxide or alumina (Al 2 O 3 ), titanium carbide (TiC), and
silicon carbide (SiC) along with pure aluminum or an aluminum alloy, are often
chosen for use in structural applications primarily because of their higher fracture
toughness and good wear-resistance properties [4, 5]. With the additions of titanium
diboride (TiB 2 ) particles to an aluminum alloy metal matrix, the elastic modulus or
stiffness of the resultant composite noticeably increases and this value is often greater
than that for the composite material obtained by the addition of reinforcements like
aluminum oxide (Al 2 O 3 ) and titanium carbide (TiC). Also, for the titanium diboride
(TiB 2 ) particulate-reinforced composites the interfacial bonding between the soft
metal matrix and the hard, brittle, and elastically deforming particulate reinforcements is influenced [6]. When compared to the base alloy both strength and stiffness
of the synthesized or engineered composite increase with the addition of particulate
reinforcements but at the expense of ductility [7].
In recent years, to fabricate aluminum alloy-based metal matrix composite
(MMC), the in situ processing technique is often preferred and chosen over the
ex situ process due essentially because of a clean interface between the soft metal
matrix and the hard and brittle reinforcement that often results in superior mechanical
properties of the engineered composite material [8, 9]. The in situ process technique
often offers many advantages to include the following [10–12]:
(a) During in situ processing the reinforcing phases are thermodynamically stable,
(b) The particulate reinforcements are distributed more homogenously through the
metal matrix, and
(c) The particulate reinforcements are free of contamination.
Mechanical properties of both Al-4.5% Cu alloy and Al-4.5%Cu/xTiB 2 composite
are influenced by the heat treatment process used. The heat treatment consists of three
distinct steps: (i) solution treatment, (ii) rapid cooling (quenching), and followed by
(iii) ageing (natural or artificial). In brief, the chosen aluminum alloy is heated to a
certain temperature at which a single solid phase exists and maintained at this temperature for a definite period of time. During this process, the solute atoms present in
a dual-phase solid solution dissolve to form a single-phase solid solution. This is
often followed by rapid cooling to conserve the solute in the solution. The cooling
must be fast enough to both arrest and/or suppress the occurrence of precipitation
and diffusion processes that could occur [13]. A saturated solution is evolved, which
contributes in a positive manner to improving the overall mechanical properties of the
synthesized or engineered composite material. Subsequent to quenching, precipitation hardening was carried out either at room temperature, referred to natural ageing,
or at an elevated temperature, referred to as artificial ageing. During artificial ageing,
S. Mozammil et al.
performance-critical end products due essentially because of their high strength
to weight ratio [σ /ρ], excellent wear resistance, adequate fatigue resistance, and
importantly overall good thermodynamic stability [1–3]. Mechanical properties of
the aluminum alloy-based metal matrix composites [denoted as AMCs] are significantly influenced by the conjoint and mutually interactive influences of matrixreinforcement bonding and the fabrication and processing route chosen and used to
process the composite material. Ceramic reinforcement particles, such as titanium
diboride (TiB 2 ), aluminum oxide or alumina (Al 2 O 3 ), titanium carbide (TiC), and
silicon carbide (SiC) along with pure aluminum or an aluminum alloy, are often
chosen for use in structural applications primarily because of their higher fracture
toughness and good wear-resistance properties [4, 5]. With the additions of titanium
diboride (TiB 2 ) particles to an aluminum alloy metal matrix, the elastic modulus or
stiffness of the resultant composite noticeably increases and this value is often greater
than that for the composite material obtained by the addition of reinforcements like
aluminum oxide (Al 2 O 3 ) and titanium carbide (TiC). Also, for the titanium diboride
(TiB 2 ) particulate-reinforced composites the interfacial bonding between the soft
metal matrix and the hard, brittle, and elastically deforming particulate reinforcements is influenced [6]. When compared to the base alloy both strength and stiffness
of the synthesized or engineered composite increase with the addition of particulate
reinforcements but at the expense of ductility [7].
In recent years, to fabricate aluminum alloy-based metal matrix composite
(MMC), the in situ processing technique is often preferred and chosen over the
ex situ process due essentially because of a clean interface between the soft metal
matrix and the hard and brittle reinforcement that often results in superior mechanical
properties of the engineered composite material [8, 9]. The in situ process technique
often offers many advantages to include the following [10–12]:
(a) During in situ processing the reinforcing phases are thermodynamically stable,
(b) The particulate reinforcements are distributed more homogenously through the
metal matrix, and
(c) The particulate reinforcements are free of contamination.
Mechanical properties of both Al-4.5% Cu alloy and Al-4.5%Cu/xTiB 2 composite
are influenced by the heat treatment process used. The heat treatment consists of three
distinct steps: (i) solution treatment, (ii) rapid cooling (quenching), and followed by
(iii) ageing (natural or artificial). In brief, the chosen aluminum alloy is heated to a
certain temperature at which a single solid phase exists and maintained at this temperature for a definite period of time. During this process, the solute atoms present in
a dual-phase solid solution dissolve to form a single-phase solid solution. This is
often followed by rapid cooling to conserve the solute in the solution. The cooling
must be fast enough to both arrest and/or suppress the occurrence of precipitation
and diffusion processes that could occur [13]. A saturated solution is evolved, which
contributes in a positive manner to improving the overall mechanical properties of the
synthesized or engineered composite material. Subsequent to quenching, precipitation hardening was carried out either at room temperature, referred to natural ageing,
or at an elevated temperature, referred to as artificial ageing. During artificial ageing,