8 Ceramics, Glasses, and Composites Free Online FlashCards

What are ceramics generally made of?

Ceramics are generally crystalline solids made from metallic and nonmetallic elements, often as oxides, carbides, or nitrides.

What does it mean that glass is amorphous?

Glass is generally amorphous: its atoms lack the repeating, long-range order found in crystals.

What are grains in a polycrystalline ceramic?

Many engineering ceramics are polycrystalline, consisting of small crystals called grains separated by grain boundaries.

Why can a small flaw cause sudden ceramic failure?

Ceramics usually deform plastically very little. A flaw can concentrate stress and allow a crack to grow suddenly, making the material brittle.

How is glass shaped into products?

Glass is shaped while softened by heat, using methods such as blowing, drawing, or forming.

How is a glass-ceramic produced?

A glass-ceramic is made by forming glass and then inducing controlled crystallization, creating crystalline regions in a residual glassy phase.

What defines a composite material?

A composite combines two or more distinct materials that remain identifiable as different phases.

What does the matrix do in a composite?

The matrix surrounds and binds the reinforcement, transfers load, and protects it.

What is anisotropy in a fiber composite?

Anisotropy is direction-dependent behavior; aligned fibers can make a composite stronger and stiffer along the fibers than across them.

How can particle reinforcement affect directional properties?

Depending on particle distribution, a particle-reinforced composite may have more similar properties in different directions than an aligned-fiber composite.

What can a damaged composite interface lead to?

Poor bonding, voids, or damage can weaken the matrix–reinforcement interface, causing separation or failure.

How can ceramic-matrix composites resist catastrophic crack growth?

Ceramic-matrix composites use fiber bridging and controlled cracking to make cracks harder to propagate, reducing catastrophic brittleness.