5 6 13 intro to solid state phase transformation
The document discusses different types of solid state phase transformations. It defines a phase as a physically distinct, chemically homogeneous and mechanically separable part of a system, which can involve state of aggregation, composition, crystal structure and electronic structure. It describes atom movements during phase transformations as either long or short range diffusion, or diffusionless changes over a fraction of an interatomic distance. The document then outlines different types of phase transformations, including changes in composition, crystal structure, compositional and crystal structure changes simultaneously, changes in order, and electronic transitions such as the Curie temperature in iron. It concludes by defining homogeneous transformations that occur simultaneously everywhere, versus heterogeneous transformations that involve nucleation and growth.
5 6 13 intro to solid state phase transformation
- 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
- 4. Types Change in composition 7/12/2013 Summer intern seminar 4 留 留1 + 留2 FCC FCC FCC 39.5 21 56 Structure Zn,at.%
- 5. Change in crystal structure 7/12/2013 Summer intern seminar 5 隆 Fe 粒 Fe 留 Fe1392属C 911属C Structure BCC FCC BCC
- 6. Compositional and crystal structure changes 7/12/2013 Summer intern seminar 6 留 supersat 留 sat + 慮 Structure FCC FCC BCT Cu,wt.% 4.5 0.3 52 Austenite Ferrite + Cementite FCC BCC Orthorhombic 0.8 0.02 6.69 Structure C,wt.%
- 7. Change in order 7/12/2013 Summer intern seminar 7
- 8. Electronic transitions I. Curie temperature in Iron (769属C) II. Neel temperature in MnO (-157属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
- 10. Reference 7/12/2013 Summer intern seminar 10