1
What is the equation to find the angle between 2 directions???
Im not writing this
Name the difference between an alloy and a pure metal.
Pure = 1 element
Alloy = More than 1 element
How many cells in a BCC and FCC crystal structure
BCC = 2
FCC = 4
What is a vacancy
A normally occupied atom which is missing.
What do the angle brackets mean???
Example: <110>
Directions of a Family
This animal is used to describe Dislocation motion
Catipiler
Planes and there negatives are _____________??
Negative.
What is a slip system
Combination of a slip plane and a slip direction.
Name 3 crystal lattice structures mentioned in class
Simple cubic (SC), Po
Body-Centered Cubic (BCC), Na, V, Li
Face centered cubic (FCC), Al, Cu, Ni
What is a polycrystalline material
collection of many small crystals or grains
What is APF and what is its equation
APF = Vs/Vc
Vs= volume of atoms in a unit cell
Vc = total unit cell volume
What is the APF of BCC and FCC
FCC APF = 0.74
BCC APF = 0.68
Do all crystalline solids contain vacancies. True or False
TRUEEEEEEEE
What does Polymorphism (allotropy) mean???
Describes a solid metal in more than one crystal structure.
Temp and pressure may affect polumorphism
Why are point defects formed.
Atomic vibrations and thermal energy
What are the 2 types of solids and describe them
Crystalline: Arranged well-ordered, repeating pattern. (Long range order)
Amorphous: Limited level of order, random, (Short range order)
What is the formula for number of atoms (N) per unit cell.
Hint:
-Ni = interior atoms
-Nf = face atoms
-Nc = corner atoms
N = Ni + Nf/2 + Nc/8
What is a unit cell
Smallest group of atoms that can be arranged in 3d to create a lattice (shoe the characteristics of lattice structure)
(Structural unit or building block of chrystal structure)
What are the two major deformation mechanisms
Slip and Twinning
What are the 3 types of line imperfections
Edge
Screw
Mixed
What is the name of a small void space that under ordinary circumstance is not occupied from an atom but a atom crowds itself in.
What is a substitutional impurity atom.
self-interstitial or interstitial site
Replaces host atom
-Higher number of grains
-Smaller grain size
-increased volume fraction (or surface area) of grain boundaries
Why 2 things explain rule of vacancy
Gibbs free energy
Helmholtz free energy
Name the 4 categories of imperfections in solids and examples in each category
Point (0D) Vacancy
Linear(1D) Dislocation
Planar(2D) Grain boundaries
Volume(3D) Inclusions and impurities
Are BCC or FCC brittle and why
BCC has high CRSS so hard to activate
FCC has low CRSS so easier to satisfy conditions to slip.