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

Discrepancies between theory and practice in Deformation. 1. Morphology of the surface in deformation. 2. The great difference between theoretical and actual strength of single crystals (. >>)

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

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

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

山西师范大学：《材料科学基础》课程教学大纲（材料化学专业）

5. 8 The Stress Around a Dislocation 1. Screw dislocation: Displacement:

Edge dislocation 1. Slip (glide) Dislocation motion vs. atom movement. Direction:l⊥讠 Plane:lb(l× Dislocation motion vs. crystal movement. → crystal movement→(dislocation motion)

1. Classification y Ideal or perfect crystal real or defect crystal According to dimension o point defect: vacancies, interstitial atoms s line defect dislocation planar defect: stacking fault o volume defect mosaic structure

1. The cause of rotation: Due to constraints, or boundary conditions imposed on the crystal. ll. The rule of rotation: