Engineering: Materials Science Basics

What is the coordination number of a Body-Centered Cubic (BCC) crystal structure?

8

Define yield strength in the context of a stress-strain curve.

The stress level at which a material begins to deform plastically and permanently.

What are the three primary classifications of solid materials?

Metals, ceramics, and polymers.

What is ductility?

A measure of a material's ability to undergo significant plastic deformation before rupture, often expressed as percent elongation.

What is the primary difference between a crystalline and an amorphous material?

Crystalline materials have a long-range periodic arrangement of atoms, while amorphous materials lack this systematic order.

Which crystal structures have the maximum theoretical Atomic Packing Factor (APF) of 0.74?

Face-Centered Cubic (FCC) and Hexagonal Close-Packed (HCP).

How is the Atomic Packing Factor (APF) mathematically defined?

APF = (Volume of atoms in a unit cell) / (Total unit cell volume).

Describe the physical nature of an edge dislocation.

A line defect where an extra half-plane of atoms is inserted into the crystal lattice, causing distortion in the surrounding planes.

What does the total area under the stress-strain curve up to the point of fracture represent?

Toughness, which is the ability of a material to absorb energy and deform plastically before breaking.

State Hooke's Law for linear elastic deformation and define the variables.

σ = Eε, where σ is stress, E is the Modulus of Elasticity (Young's Modulus), and ε is strain.