BMEE209L: Module 2

Question 1

Example of simple cubic

Answer 1

Polonium

Question 2

Example of BCC

Answer 2

Group 1 metals and Cr, V, Fe

Question 3

Example of FCC

Answer 3

Group 11 (Cu,Au,Ag) and Al, Ni, Pb

Question 4

Example of HCP

Answer 4

Group 2 metals and Zinc, Ti

Question 5

Volume of a HCP unit cell

Answer 5

6sqrt(3)R^2

Question 6

Density of a metal

Answer 6

ρ = nA/VcNa

where n = number of atoms in unit cell
A = atomic weight
Vc = volume of unit cell
Na = avogadro’s constant

Question 7

In crystallographic notations what will you do when you face a negative number?

Answer 7

put a bar above the number instead of the negative sign

Question 8

In crystallographic notations what will you do when you face a fraction?

Answer 8

multiply the entire set by a number to eliminate the fraction

Question 9

direction vectors are enclosed in….

Answer 9

square brackets [hkl]

Question 10

plane vectors are enclosed in…..

Answer 10

parenthesis (hkl)

Question 11

distance between planes

Answer 11

d(hkl) = a/sqrt(h^2+k^2+l^2)

Question 12

Linear Density

Answer 12

number of atoms on vector/length of vector

Question 13

Planar Density

Answer 13

number of atoms on plane/area of plane

Question 14

Angle between planes

Answer 14

cos θ = (h1h2 + k1k2 + l1l2)/(sqrt(h1^2+k1^2+l1^2)sqrt(h2^2+k2^2+l2^2))

Question 15

Weiss’s Zone law

Answer 15

If direction [uvw] is orthogonal to plane (hkl): hu + kv + wl = 0

Question 16

Number of vacancies (Nv)

Answer 16

Nv = Ne^-Ev/KbT

where
N = number of sites
Kb = Boltzmann Constant (8.617x10^-5)
Ev = energy of vacancy

Question 17

Number of available sites (Ns)

Answer 17

Ns = Naρ/A

Question 18

Critical Resolved Stress

Answer 18

σy = τ/cosθcosφ

where T = tensile force in the y direction
θ = angle b/w object axis and slip plane normal
φ = angle b/w object axis and slip direction