Material Sscience And Engineering Exam Questions
And Answers Verified 100% Correct
Atomic Packing Factor - ANSWER -indicates amount of atoms in unit
cell
- APF = volume of atoms in unit cell/volume of unit cell
- number of atoms x volume of atom / a^3
Simple Cubic (SC) - ANSWER -APF = 0.52
1 atom/unit
cell a = 2R
Body Centered Cubic (BCC) - ANSWER -APF = 0.68
2 atoms/unit
cell a = (4/√3)R
Face Centered Cubic (FCC) - ANSWER -APF = 0.74
4 atoms/unit cell a
= 2R√2 Hexagonal
Close-Packed
(HCP) - ANSWER -
APF = 0.74
6 atoms/unit cell a
= 2R
Common in metallic crystals
, Theoretical Density - ANSWER -P = (n*A)/(Vc*Na)
Miller Indices - ANSWER -A set of three integers (four for hexagonal)
that designate crystallographic planes, as determined from
reciprocals of fractional axial intercepts
(1/a, 1/b, 1/c) = (hkl)
How to calculate Miller Indices - ANSWER -1.) find intercepts in terms
of a, b, c
2.) find reciprocals
3.) reduce to lowest integer values
4.) enclose in parentheses
Linear Density - ANSWER -equivalent directions have identical linear
densities
- LD = n/(unit length of direction vector)
Planar Density - ANSWER -planes with the same planar density are
equivalent
- PD = 1/(a^2)
Crystallographic Planes - ANSWER -parallel planes of atoms in a
crystal lattice
-parallel to each other = equivalent planes
HCP Crystallographic Directions - ANSWER --Read off projections in
terms of unit cell dimensions a1, a2, a3, or c
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And Answers Verified 100% Correct
Atomic Packing Factor - ANSWER -indicates amount of atoms in unit
cell
- APF = volume of atoms in unit cell/volume of unit cell
- number of atoms x volume of atom / a^3
Simple Cubic (SC) - ANSWER -APF = 0.52
1 atom/unit
cell a = 2R
Body Centered Cubic (BCC) - ANSWER -APF = 0.68
2 atoms/unit
cell a = (4/√3)R
Face Centered Cubic (FCC) - ANSWER -APF = 0.74
4 atoms/unit cell a
= 2R√2 Hexagonal
Close-Packed
(HCP) - ANSWER -
APF = 0.74
6 atoms/unit cell a
= 2R
Common in metallic crystals
, Theoretical Density - ANSWER -P = (n*A)/(Vc*Na)
Miller Indices - ANSWER -A set of three integers (four for hexagonal)
that designate crystallographic planes, as determined from
reciprocals of fractional axial intercepts
(1/a, 1/b, 1/c) = (hkl)
How to calculate Miller Indices - ANSWER -1.) find intercepts in terms
of a, b, c
2.) find reciprocals
3.) reduce to lowest integer values
4.) enclose in parentheses
Linear Density - ANSWER -equivalent directions have identical linear
densities
- LD = n/(unit length of direction vector)
Planar Density - ANSWER -planes with the same planar density are
equivalent
- PD = 1/(a^2)
Crystallographic Planes - ANSWER -parallel planes of atoms in a
crystal lattice
-parallel to each other = equivalent planes
HCP Crystallographic Directions - ANSWER --Read off projections in
terms of unit cell dimensions a1, a2, a3, or c
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