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King Fahd University of Petroleum & Minerals
Mechanical Engineering Department
ME 205: Materials Science
Semester (151)
Homework # _2_
Assigned on: 30/09/2015
Due date: 07/10/2015
(Please, use this page as a cover page)
Name:
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ID#:
Section #: _________
Problems
Marks Grades
1
10
2
15
3
10
4
10
5
15
6
20
7
20
Total
100
1
1)
Show that the atomic packing factor for BCC is 0.68.
2
2)
Show that the atomic packing factor for HCP is 0.74.
3
3)
Calculate the radius of a vanadium atom, given that V has a BCC
crystal structure, a density of 5.96 g/cm3, and an atomic weight of
50.9 g/mol.
4
4)
Iodine has an orthorhombic unit cell for which the a, b, and c lattice
parameters are 0.481, 0.720, and 0.981 nm, respectively.
(a) If the atomic packing factor and atomic radius are 0.547 and 0.177
nm, respectively, determinethe number of atoms in each unit cell.
(b) The atomic weight of iodine is 126.91 g/mol; compute its
theoretical density.
5
5)
Titanium has an HCP unit cell for which the ratio of the lattice
parameters c/a is 1.58. If the radius of the Ti atom is 0.1442 nm, (a)
determine the unit cell volume, and (b) calculate the density of Ti and
compare it with the literature value.
6)
(a) Derive linear density expressions for BCC [110] and [111]
directions in terms of the atomic radius R. (b) Compute and compare
linear density values for these same two directions for tungsten.
6
7
7)
(a) Derive planar density expressions for FCC (100) and (111) planes
in terms of the atomic radius R.
(b) Compute and compare planar density values for these same two
planes for nickel.
8
9
10