Department: Mechanical
Department
Subject: Metallurgy
Assignment (2): Crystal
structure
Lecturer: Dr. Shaimaa Mostafa
Assistants: E. Doaa Bakr
Academic Year: 2018 -2019
Semester: Spring
1- What is the relationship between the length of the side a of the BCC unit cell
and the radius of its atoms?
2- How many atoms per unit cell are there in the FCC crystal structure?
3- Calculate the volume of an FCC unit cell in terms of the atomic radius R.
4- Show that the atomic packing factor for the FCC crystal structure is 0.74 and
for BCC is 0.68.
5- If the atomic radius of aluminum is 0.143 nm, calculate the volume of its unit
cell in cubic meters if Al has FCC crystal structure.
6- Calculate the radius of a palladium atom, given that Pd has an FCC crystal
structure, a density of 12.0 g/cm3, and an atomic weight of 106.4 g/mol.
7- 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.
8- Iron has a BCC crystal structure, an atomic radius of 0.124nm, and an
atomic weight of 55.9 g/mol. compute the theoretical density of Iron.
9- Some hypothetical metal has the simple cubic crystal structure shown in
Figure. If its atomic weight is 74.5 g/mol and the atomic radius is 0.145
nm, compute its density.