3. 1 Basic concepts of al loys 1. Definition An alloy is the combination of metal(s) with other elements through chemical bonding. Termino logy

1. Deformation process of polycrystalline materials Deformation process of industrial material consists of three stages Elastic. which is reversible

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)

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

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

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

山西师范大学：《材料科学基础》课程教学大纲（材料化学专业）