Question

Which factor is most critical when selecting a matrix material for a high-temperature composite application?

• A. Electrical conductivity
• B. Thermal expansion coefficient
• C. Optical transparency
• D. Magnetic responsiveness

Hint:

Composite Materials. Compatibility between matrix and reinforcement is key. For high-temperature applications, matching the Coefficient of Thermal Expansion (CTE) is critical to avoid thermally induced stresses and damage.

Answer 1

The Correct Option is B

In composite materials, especially those intended for high-temperature applications (like ceramic matrix composites or metal matrix composites), compatibility between the reinforcement phase (e.
g.
, fibers) and the matrix material is crucial.
One of the most critical factors is the matching of their Coefficients of Thermal Expansion (CTE).
A significant mismatch in CTE between the matrix and reinforcement can lead to large internal stresses developing during temperature changes (heating during operation, cooling during manufacturing).
These stresses can cause matrix cracking, fiber-matrix debonding, or even failure of the composite component.
While other properties like temperature resistance of the matrix itself are vital, the CTE match with the reinforcement is critical for structural integrity across temperature ranges.
Electrical, optical, and magnetic properties are secondary unless required for a specific function beyond structural performance at high temperature.