Classification of composite materials

Classification of composite materials

Composite materials can be classified based on the matrix phases and types of reinforcement phases in the matrix phase. Metal matrix composites (MMC), ceramic matrix composites (CMC) and polymer matrix composites (PMC) are the various types of composites based on matrix phase. While, two major types of reinforcement based composites are layered composite and phase composite.

 Composites based on selection of matrix phase

The matrix phase type of composite depends upon the selection of matrices such as metal matrix composite, polymer matrix composite, and ceramic matrix composite. When metal is selected as matrix phase then the composite is termed as metal matrix composite.
In the same way if polymer and ceramic are selected as matrix phase then composites are called polymer and ceramic matrix composite respectively. Fig. shows the classification of composite depending upon the selection of matrix phases.

Classification of composite materials
Classification of composite materials

 

Metal matrix composite (MMC)

Metal matrix composites (MMCs) are such type of composite in which matrix phase is a metal like Aluminum, magnesium, titanium and so on. Metal matrix composite is not much popular as compared to polymer matrix composite (PMC), because of the high density of metals. However, metals have high strength and stiffness, as well as metal can withstand higher temperature than polymeric materials.

  Polymer matrix composite (PMC)

In polymer matrix composites, polymer is used matrix phase, whereas, organic, inorganic or hybrid materials are used as reinforcement phase. Polymer matrix composites have several advantages over metal and ceramic matrix composites, such as low density, high extensibility, high shock absorption capacity, low cost for fabrication etc. Therefore, polymer matrix composites are more popular than metal and ceramic matrix composite.  Now a days fibre reinforced polymer composites materials used more than 90% (by weight) of the total composites. Whereas, metal matrix composites are widely used over PMC where high service temperature, high strength are required.

 Ceramic matrix composite

In ceramic matrix composite (CMC), ceramic as a major constituent, whereas, metal or other inorganic materials are used as reinforcement phase. Ceramics have high melting point temperature, high compressive strength, good strength at elevated temperature and excellent resistance to oxidation. However, ceramics have low tensile strength, impact strength, and these shortcomings of ceramic can be improved by selecting suitable reinforcing materials.

 

Composite materials are materials composed of two or more distinct constituents, each with different physical or chemical properties, which combine to produce a material with characteristics different from those of its individual components. These materials are widely used in various industries due to their tailored properties, such as high strength-to-weight ratio, corrosion resistance, and thermal stability. Classification of composite materials can be based on different criteria, including the type of reinforcement, matrix material, and the processing method. Here are some common classifications:

Based on Reinforcement Type:

Fiber-Reinforced Composites: Fibers, such as glass, carbon, or aramid, are embedded in a matrix material (polymer, metal, or ceramic).
Glass Fiber-Reinforced Composites (GFRP): Commonly used for low-cost applications.
Carbon Fiber-Reinforced Composites (CFRP): Known for high strength and low weight.
Aramid Fiber-Reinforced Composites (AFRP): Exhibit high impact resistance and strength.
Particulate-Reinforced Composites: Small particles (e.g., metal, ceramic) are dispersed in a matrix.
Laminar Composites: Consist of layers (laminae) of different materials bonded together.
Metal Matrix Composites (MMC): Metal matrix reinforced with ceramic particles or fibers.

Based on Matrix Material:

Polymer Matrix Composites (PMCs): Polymer resins (e.g., epoxy, polyester) are used as the matrix.
Metal Matrix Composites (MMCs): Metal matrices (e.g., aluminum, titanium) are used.
Ceramic Matrix Composites (CMCs): Ceramic matrices (e.g., silicon carbide, alumina) are employed.

Based on Processing Method:

Continuous Fiber-Reinforced Composites: Long fibers are used for reinforcement.

Prepreg Composites: Fibers pre-impregnated with resin.
Filament-Wound Composites: Continuous fibers wound around a mandrel.
Discontinuous Fiber-Reinforced Composites: Short fibers or particulates are used.

Injection-Molded Composites: Short fibers mixed with a polymer matrix and molded.
Compression-Molded Composites: Fibers are randomly oriented in a matrix and compressed.
Sheet Molding Compound (SMC): Fibers in a thermosetting resin compressed in sheet form.

Based on Application:

Structural Composites: Used for load-bearing structures in aerospace, automotive, and civil engineering.
Functional Composites: Designed for specific functional properties, such as thermal, electrical, or magnetic conductivity.

Based on Temperature Resistance:

High-Temperature Composites: Designed to withstand elevated temperatures, often using ceramic matrices and fibers.

Based on Usage in Industries:

Aerospace Composites: Designed for lightweight and high-strength applications in aircraft and spacecraft.
Automotive Composites: Used to reduce vehicle weight and improve fuel efficiency.
Construction Composites: Employed in building materials for their strength and durability.

 

Based on Fiber Architecture:

Unidirectional Composites: Fibers are aligned in one direction, providing strength along that axis.
Bidirectional Composites: Fibers are aligned in two perpendicular directions (e.g., woven fabrics), offering strength in both directions.
Multidirectional Composites: Fibers are oriented in multiple directions to provide isotropic or anisotropic properties as needed.


Based on Fiber Length:

Short Fiber-Reinforced Composites (SFRP): Fibers are relatively short (typically <1 cm) and randomly oriented.
Long Fiber-Reinforced Composites (LFRP): Fibers are longer (usually several centimeters) and aligned for improved strength and stiffness.


Based on Hybrid Composites:

Hybrid Composites: Combine different types of fibers or reinforcements within the same matrix for a synergistic effect.
Functionally Graded Composites: Gradual variation in composition to achieve specific performance gradients.


Based on Manufacturing Process:

Autoclave-Cured Composites: Manufactured using high-pressure autoclaves for precise control over temperature and pressure during curing.
Resin Transfer Molding (RTM): Liquid resin injected into a mold containing the reinforcing material.
Pultrusion: Continuous fibers pulled through a resin bath and then through a heated die to cure and shape the composite.


Based on Environmental Impact:

Green Composites: Use environmentally friendly or bio-derived materials as part of the composite structure.


Based on Smart or Advanced Materials:

Smart Composites: Include materials with embedded sensors, actuators, or other functionalities for applications in smart structures or systems.


Based on Specific End-Use:

Ballistic Composites: Designed for applications requiring resistance to projectiles, often used in body armor and vehicle armor.
Thermoplastic Composites: Utilize thermoplastic matrices, allowing for remolding and recycling.


Based on Conductive Properties:

Conductive Composites: Contain materials with electrical conductivity, often used in electronic and electromagnetic applications.


Based on Bio-composites:

Natural Fiber Composites: Use fibers derived from natural sources, such as flax, hemp, or bamboo, as reinforcements in a polymer matrix.


Based on Nanocomposites:

Nanocomposites: Incorporate nanoscale reinforcements (e.g., carbon nanotubes, nanoclays) to enhance mechanical, thermal, or electrical properties.


Based on Damage Tolerance:

Self-Healing Composites: Contain materials that can repair damage autonomously, enhancing the material’s durability.


These additional classifications reflect the diverse nature of composite materials and highlight their adaptability for a wide range of applications in different industries. The choice of classification often depends on the specific requirements and desired properties for a particular application.

These classifications provide a broad overview of the various ways composite materials can be categorized, and there is often overlap between these categories based on specific application requirements.

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