Ciencia De Los Materiales
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Publicado: 2 de marzo de 2013
FACULTAD DE INGENIERÍAS
Ciencia de los Materiales
Taller #2
Workshop on crystalline structure of metals
1. For crystalline structures BCC, FCC andHCP describe or demonstrate, according to the case, the following characteristics:
a. Lattice points.
b. Number of atoms per unit cell. For an atom that isshared with m adjacent unit cells, we only count a fraction of the atom, 1/m.
c. The coordination number, which is the number of closest neighbors to which an atom isbonded.
d. Radio to lattice parameter relation.
e. Cell volume.
f. APF, the atomic packing factor, which is the fraction of the volume of the cell actuallyoccupied by the hard spheres.
2. Calculate the atomic radius in cm for the following: (a) BCC metal with ao = 0.35089 nm and one atom per lattice point; and (b) FCCmetal with ao = 3.5167 Å.
3. The density of potassium, which has the BCC structure and one atom per lattice point, is 0.855 g/cm3. The atomic weight of potassium is39.09 g/mol. Calculate (a) the lattice parameter; and (b) the atomic radius of potassium.
4. A metal having an HCP structure has an atomic weight of 24.31 g/mol, and alattice parameter of 3.2087 Å. Determine the density of the metal.
5. Thorium is a metal that has a FCC structure. It has a density of 11.72 g/cm3 and an atomic weight of232 g/mol. Calculate:
g. The lattice parameter, a0.
h. The atomic radius of Th.
6. A metallic material has a tetragonal structure with lattice parametersa0=0.32517 nm and c0= 0.49459 nm. The density is 7.286 g/cm3 and the atomic weight is 114.82 g/mol. In which cell type this material crystallizes (Face or Body centered)?
Ciencia de los Materiales
Taller #2
Workshop on crystalline structure of metals
1. For crystalline structures BCC, FCC andHCP describe or demonstrate, according to the case, the following characteristics:
a. Lattice points.
b. Number of atoms per unit cell. For an atom that isshared with m adjacent unit cells, we only count a fraction of the atom, 1/m.
c. The coordination number, which is the number of closest neighbors to which an atom isbonded.
d. Radio to lattice parameter relation.
e. Cell volume.
f. APF, the atomic packing factor, which is the fraction of the volume of the cell actuallyoccupied by the hard spheres.
2. Calculate the atomic radius in cm for the following: (a) BCC metal with ao = 0.35089 nm and one atom per lattice point; and (b) FCCmetal with ao = 3.5167 Å.
3. The density of potassium, which has the BCC structure and one atom per lattice point, is 0.855 g/cm3. The atomic weight of potassium is39.09 g/mol. Calculate (a) the lattice parameter; and (b) the atomic radius of potassium.
4. A metal having an HCP structure has an atomic weight of 24.31 g/mol, and alattice parameter of 3.2087 Å. Determine the density of the metal.
5. Thorium is a metal that has a FCC structure. It has a density of 11.72 g/cm3 and an atomic weight of232 g/mol. Calculate:
g. The lattice parameter, a0.
h. The atomic radius of Th.
6. A metallic material has a tetragonal structure with lattice parametersa0=0.32517 nm and c0= 0.49459 nm. The density is 7.286 g/cm3 and the atomic weight is 114.82 g/mol. In which cell type this material crystallizes (Face or Body centered)?
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