1. Introduction to solid state
phase transformation
R.Arul Vigneswar
7/12/2013 Summer intern seminar 1
2. Phase
• “Physically distinct, chemically homogeneous and mechanically
separable part of a system”
• Involves
I. State of aggregation
II. Composition
III. Crystal structure
IV. Electronic structure
7/12/2013 Summer intern seminar 2
3. Atom movements
• Movements over
a. A large number of interatomic distance (ex. Long range diffusion)
b. One or two interatomic distance (ex. Short range diffusion)
c. Fraction of interatomic distance (ex. Diffusionless changes)
7/12/2013 Summer intern seminar 3
7. • Change in order
7/12/2013 Summer intern seminar 7
8. • Electronic transitions
I. Curie temperature in Iron (769°C)
II. Neel temperature in MnO (-157°C)
7/12/2013 Summer intern seminar 8
9. Homogeneous and heterogeneous
transformations
• Homogeneous transformation- takes place simultaneously in all parts
• Heterogeneous transformation- nucleation and growth type
7/12/2013 Summer intern seminar 9