6. 8 Diffusion Mechani sm Flick's' law in microscopic form 1. One dimensional diffusion. jump frequency period probability of atom jumping to nearest position

1. There have no two-phases area in diffusion area, every layer is single-phases 2. Phase's interface moves according to parabola law 3. Phase's width

36. 5 concentration dependence of D. Matano method d -C- dependence ll Matano method

(for one dimensional diffusion only 1. Infinite system 1. Formula

I Atom movement in sol ids mechanical movement thermal vibration (short-range migration) Thermal motion diffusion(long-range migration)

5. 19 Reaction between Dislocation Condition 1. Geometrical condition

Back stress exerted by obstacle on leading dislocation. (It is supposed to be a short-range-force.) nrbdx =tpbdx dx virtual displacement

By cottrell atmosphere model, we can explain the sharp yielding phenomenon

5.16 Dislocation in FCC crystals Perfect dislocation b =na, +nb. +nC

Introduction 1. Definition: Fis a fictitious force which is supposed to be responsible for the motion of dislocation. Fll Criterion: The work done on crystal by stress must be equal to that done on dislocation by force F. 2. Principle of derivation of F: Macroscopic work=microscopic work (or deformation work)