Ch. 4 Imperfections in solids

Question 1

Solidification process

Answer 1

crystals nuclei starts appearing, nuclei starts to grow to form crystals or grains

Question 2

Types of imperfections

Answer 2

point, line, area

Question 3

Examples of point defects

Answer 3

vacancy atoms, interstitial atoms, substitutional atoms

Question 4

Example of line defects

Answer 4

Dislocation(line and twist)

Question 5

Examples of area defects

Answer 5

grain boundaries

Question 6

EQ for concentration of point defects

Answer 6

Nv/N = exp(-Qv/kT) Nv vacancies per unit ^3, N = atoms per unit ^3, k = Boltzmanns constant

Question 7

N formula

Answer 7

N = NaP/A (1 mol * density)/atomic mass)

Question 8

Requirements for subsitutional solid solution

Answer 8

delta 15%, similar electronegativity, same crystal stucture, same valency

Question 9

Composition percentage formula by weight

Answer 9

C1 = m1/(m1+m2) * 100

Question 10

Edge dislocations vector

Answer 10

line perpendicular to Burgers vector

Question 11

Screw dislocations vector

Answer 11

// to burgers vector

Question 12

Surface Defects

Answer 12

Grain boundaries, Bulk/Volume Defects

Question 13

Examples of bulk/volume defects

Answer 13

cracks, pores, etc..

Question 14

How to observe crystal structures

Answer 14

Section cut & grind, polish, etching, microscope

Question 15

Grain size detetmination

Answer 15

AVG grain diameter = L/NgM (magnification)

Question 16

ASTM Grain Size no

Answer 16

n(grains per inch^2)
@ 100x) = 2^(G-1)