Which statement best describes a composite material?

Which statement best describes a composite material?

• A. It is formed by two or more substances with unique properties
• B. It is always metallic
• C. It cannot be lighter than its components
• D. It has uniform properties

Answer: (B)

Composite materials are made from two or more substances with different properties that, when combined, create a new material with properties that differ from and are often improved over the individual components. Usually there’s a matrix that holds everything together and a reinforcing phase (like fibres) that provides strength or stiffness, allowing you to tailor things like density, stiffness, and toughness. For example, carbon fibre–reinforced polymer is strong and light, while concrete blends cement with aggregates to boost compressive strength. Because the reinforcement is oriented or distributed in specific ways, composites can show directional, non-uniform properties rather than being perfectly uniform in all directions. They aren’t limited to metals; many are polymer- or ceramic-based. This combination of distinct constituents yielding new, engineered properties is what makes the description the best fit.

Composite materials are made from two or more substances with different properties that, when combined, create a new material with properties that differ from and are often improved over the individual components. Usually there’s a matrix that holds everything together and a reinforcing phase (like fibres) that provides strength or stiffness, allowing you to tailor things like density, stiffness, and toughness. For example, carbon fibre–reinforced polymer is strong and light, while concrete blends cement with aggregates to boost compressive strength. Because the reinforcement is oriented or distributed in specific ways, composites can show directional, non-uniform properties rather than being perfectly uniform in all directions. They aren’t limited to metals; many are polymer- or ceramic-based. This combination of distinct constituents yielding new, engineered properties is what makes the description the best fit.