1. What is difference between crystal structure and crystal system. Explain types of crystal structure and axial
relationships?
A crystal structure is described by both the geometry of, and atomic arrangements
within, the unit cell, whereas a crystal system is described only in terms of the unit
cell geometry. For example, face-centered cubic and body-centered cubic are crystal
structures that belong to the cubic crystal system.
Different types of crystal structure and axial relationships are:
2. Describe the major imperfections that may present in crystal structure of metals. How do they influence the
mechanical properties of materials?
The major imperfections that may present in crystal structure of metals are:
Point Defects: When The dendrite – chp 3 pg 12
Vacancy - decrease in density and increases the entropy
3. With neat sketches describe any four types of point defects in metallic materials.
Same as above
4. Define unit cell of a space lattice. Derive the effective number of lattice point in unit cell of cubic lattices
5.
6. A unit cell isthe smallest portion of a crystal lattice that shows the three-dimensional pattern of the entire
crystal. A crystal can be thought of as the same unit cell repeated over and over in three dimensions.
