What are crystalline materials? What are non-crystalline materials? What is allotropic? What is polymorphic? What are unit cell, lattice constant and the number of atoms per unit cell? What is the number of atoms of BCC, FCC and HCP?

Materials Science

HW of ETM 307 Chapter 4 of ETM307: Crystal Structure  80 points in total

1. What are crystalline materials? What are non-crystalline materials? (5 points)
2. What is allotropic? What is polymorphic? (5 points)
3. What are unit cell, lattice constant and the number of atoms per unit cell? What is the number of atoms of BCC, FCC and HCP? (10 points)

4. What is the atomic packing factor? What are the atomic packing factors of BCC, FCC and HCP? Does the volume increase or decrease when FCC iron changes to BCC iron? Why? (10 points)

5. What are the families of crystal directions and planes? (10 points)
6. What are the closest packed crystalline direction and plane of BCC and FCC? (10 points)
7. What are the similarity and difference between FCC and HCP crystal structures? (10 points)
8. What are the Miller indexes of two crystal directions and one crystal plane in the following figure? (10 points)
9. Please identify the Miller-Bravais’ indexes of the crystal direction and plane indicated in the following hexagonal