Material Science Chapters 3-4 Study Guide

These flashcards cover key concepts and definitions from the study guide on the crystal structure of solids and imperfections/defects in materials.

What is the difference between crystalline and amorphous solids?

Crystalline solids have properly arranged atoms, while amorphous solids have no long-range atomic order.

What is a single crystal material?

A single crystal has a continuous and unbroken lattice structure, exhibiting anisotropic mechanical behavior.

What characterizes polycrystalline materials?

Polycrystalline materials consist of many small crystals (grains) with grain boundaries that can influence their mechanical properties.

What does it mean for a material to be isotropic?

Isotropic materials have uniform mechanical properties in all directions, typically observed in randomly oriented polycrystalline grains.

What is the Atomic Packing Factor (APF) for FCC?

APF for FCC is 0.74, meaning 74% of the volume is occupied by atoms.

What are Miller Indices used for?

Miller Indices are used to represent planes and directions in crystals.

What are the types of point defects in solids?

Point defects include vacancies, interstitials, and substitutional impurities.

What is the formula for the theoretical density of a unit cell?

The formula is p = nA/VcNA, where n is the number of atoms per unit cell, A is the atomic weight, Vc is the volume of the unit cell, and NA is Avogadro's number.

What are the characteristics of High-Entropy Alloys (HEAs)?

HEAs contain multiple principal elements and tend to form stable solid solutions due to high configurational entropy.

How do precipitates enhance material performance?

Precipitates strengthen materials by blocking dislocation motion and are introduced during cooling after being initially soluble.