Composite materials are engineered from two or more distinct constituents, resulting in properties that differ from the individual components. The key components are matrix materials, which bind reinforcements, and reinforcement materials, which provide strength and stiffness. Types of composites include polymer, metal, and ceramic matrix composites, with manufacturing processes such as lay-up and injection molding used to create them.

1. Introduction to Composite
Material:
Lect # 10
Applied Chemistry

2. Definition:
• Composite materials are engineered materials
made from two or more constituent materials
with significantly different physical or chemical
properties, which when combined, produce a
material with characteristics different from the
individual components. These materials are
designed to achieve specific performance
requirements that cannot be met by
conventional materials alone.

3. Key components and characteristics
of composite materials:
• Here's a breakdown of the key components and
characteristics of composite materials:
• Matrix Material
• Reinforcement material

4. Matrix Material:
• Definition: The matrix material in a composite is the continuous
phase that surrounds and binds the reinforcement materials
together.
• Function: It holds the reinforcement materials in place, transfers
loads between the reinforcements, and provides protection against
environmental factors such as moisture, chemicals, and
temperature.
• Characteristics: Matrix materials are typically chosen for their
ability to flow, wet, and adhere to the reinforcement materials. They
can be polymers (e.g., epoxy, polyester, vinyl ester), metals (e.g.,
aluminum, titanium), or ceramics (e.g., silicon carbide, aluminum
oxide).
• Properties: Matrix materials contribute to the composite's final
properties such as toughness, flexibility, chemical resistance, and
thermal stability.
• Examples: Epoxy resins are commonly used as matrix materials in
carbon fiber reinforced polymers (CFRP), while aluminum alloys
can serve as matrix materials in metal matrix composites (MMCs).

5. Reinforcement Material:
• Definition: The reinforcement material in a composite provides strength,
stiffness, and other desired properties to the composite. It is dispersed within
the matrix material.
• Function: Reinforcement materials carry the applied loads and provide
structural integrity to the composite. They resist deformation and enhance
mechanical properties such as tensile strength, compression strength, and
impact resistance.
• Characteristics: Reinforcement materials are typically fibrous or particulate
in nature and are chosen for their high strength-to-weight ratio and specific
properties. Common reinforcement materials include carbon fibers, glass
fibers, aramid fibers, ceramic fibers, and various types of particles (e.g., silicon
carbide, aluminum oxide).
• Properties: Reinforcement materials contribute to the composite's final
properties such as strength, stiffness, fatigue resistance, and dimensional
stability.
• Examples: Carbon fibers are widely used as reinforcement materials in CFRP
due to their high strength and low weight. Glass fibers are common in
fiberglass composites, offering good strength and affordability.

7. Types of Composites:
• Polymer Matrix Composites (PMCs): These
are composites where the matrix material is a
polymer. Examples include fiberglass and carbon
fiber reinforced polymers.
• Metal Matrix Composites (MMCs): In these
composites, the matrix material is a metal. They are
known for their high strength, stiffness, and
excellent thermal properties.
• Ceramic Matrix Composites (CMCs): Here, the
matrix material is a ceramic. They offer exceptional
high-temperature performance and are used in
aerospace and automotive applications.

8. Manufacturing Processes:
• Composite materials can be fabricated using various
techniques, including:
• Lay-up: Layering reinforcement materials and
impregnating them with a matrix material.
• Filament Winding: Wrapping fibers around a
rotating mandrel to create parts with high strength
and stiffness.
• Injection Molding: Injecting a matrix material
into a mold containing reinforcement materials.
• Pultrusion: Pulling fibers through a resin bath and
then through a shaping die to create continuous
lengths of composite profiles.

9. Classification on the basis of
reinforcement material:
• The three primary categories are:
• Fiber-Reinforced Composites:
• Particulate-Reinforced Composites:
• Hybrid Composites:

10. Fiber-Reinforced Composites:
• Definition: These composites incorporate fibers as the
reinforcement material, which are typically embedded within a
matrix material.
• Types:
• Carbon Fiber Reinforced Composites (CFRP): Carbon fibers
offer exceptional strength, stiffness, and low weight, making CFRP
ideal for high-performance applications such as aerospace,
automotive, and sports equipment.
• Glass Fiber Reinforced Composites (GFRP): Glass fibers are
affordable and offer good strength and stiffness. GFRP finds
applications in construction, marine, automotive, and consumer
goods.
• Aramid Fiber Reinforced Composites (AFRP): Aramid fibers,
such as Kevlar, provide high strength and impact resistance. AFRP
is commonly used in ballistic armor, aerospace, and sporting goods.
• Natural Fiber Reinforced Composites: Fibers derived from
plants (e.g., bamboo, hemp) or animals (e.g., wool, silk) can be used
as reinforcement in composites, offering sustainability benefits and
unique properties. They find applications in automotive interiors,
construction, and packaging.

11. Carbon-fibre Glass Fibre
Aramid-fibre

12. Particulate-Reinforced Composites:
• Definition: These composites incorporate particulate
materials, such as powders or flakes, as the reinforcement
phase dispersed within a matrix material.
• Types:
▫ Metal Matrix Composites (MMCs): Metal matrix composites
contain metal matrices reinforced with ceramic or metallic
particles or fibers. MMCs offer high strength, stiffness, and
thermal properties, making them suitable for aerospace,
automotive, and electronics applications.
▫ Ceramic Matrix Composites (CMCs): CMCs consist of
ceramic matrices reinforced with ceramic fibers or particles. They
exhibit high-temperature resistance, wear resistance, and
excellent thermal and chemical properties, making them suitable
for aerospace, gas turbine engines, and automotive applications.

13. Metal-matrix
Ceramic-matrix

14. Hybrid Composites:
• Definition: Hybrid composites incorporate multiple types of
reinforcement materials within a single matrix material,
combining the benefits of each material type.
• Types:
• Hybrid Fiber Composites: These composites combine
different types of fibers (e.g., carbon, glass, aramid) to achieve
a balance of strength, stiffness, and cost-effectiveness.
• Hybrid Particulate Composites: These composites
combine particulate reinforcements with fiber reinforcements
to enhance specific properties such as wear resistance,
thermal conductivity, or electrical conductivity.
These classifications based on reinforcement materials provide
a framework for understanding the diverse range of composite
materials available and their applications across various
industries.