Chapter 10 Review

Question 1

What are the Hume-Rothery Rules?
(for an alloy of two metals)

Answer 1

1.) atoms must have < 15% variation in atomic radius
2. Crystal Structure (must be the same; FCC, BCC, HCP)
3. Valence (must be the same)
4. Electronegativity (approximately the same)

Question 2

What is a ‘phase’?

Answer 2

1. A phase has the same structure throughout (e.g. FCC, BCC, etc.)
2. A phase has roughly the same composition and properties throughout
3. A definite interface exists between a phase and any other phases

Question 3

What is Gibb’s Phase Rule?

Answer 3

2 + C = F + P

C: # of chemically independent components.
P: # of phases present (e.g. liquid, vapor, solid)
F: # of degrees-of-freedom (i.e. # variable that change independantly)
2: assumes pressure and temperature are independent variables.