material Science Flashcards
Final Exam
How are Crystalline Solids aligned?
Atoms are arranged in regular/ repeating way
How are Amorphous Solids aligned?
lack of regular arrangement/ unrepeating in long-range
Why are crystal Solids made?
Lower energy state
Why amorphous Solids made?
Not enough time to arrange
what are the most important crystal structures for metals?
Cubic and Hexagonal
What are the three crystals structures for metals?
Body Centered Cubic (BCC)
Face Centered Cubic (FCC)
Hexagonal Close-packed (HCP)
Can metals and non metals have more then one crystalline structure?
Yes, at different temperature
What is APF?
Atomic Packing Factor
What is HCP’s stacking sequence?
ABAB
What is FCC’s stacking sequence?
ABCABC
What is HCP and FCC’s APF?
0.74
How many Atoms in a HCP’s Unit cell?
6
What is the c/a ration for HCP crystal?
1.633
What is Coordination number?
Number of nearest neighbors (touching number of spheres)
What is BCC Coordination Number?
8
