Under normal stress σ=Εε

Under shear stress τ=Gγ

Bauschinger effect: Loading in the same direction (elastic limit) increases and loading in the opposite direction decreases

Elastic aftereffect: Within the elastic limit, strain lags behind the applied stress and is related to time.

elastic hysteresis

Cyclic toughness

Slip (mainly): ① Uneven, concentrated on certain crystal planes; ② Translational sliding relative to the sliding two parts of the crystal orientation relationship remains unchanged; ③; ④ The slip line forms a certain angle with the stress axis; the slip line precedes Slip surface appears

Critical shear stress: τ=(F/A)COSΦcosλ=σ₀m (orientation factor)

Slip system: composed of a slip surface (closest packed plane of atoms) and a slip direction (closed packed direction)

twin

twist

diffusive deformation

grain boundary sliding

grain boundary movement

Hall Page: σs＝σ₀＋Kd⁻½

fine grain strengthening

Factors affecting solid solution strengthening: ① The atomic fraction of solute atoms; ② The atomic size difference between solute atoms and matrix metal; ③ Interstitial solute atoms > substitutional solute atoms ④ Difference in the number of valence electrons

Upper yield point: dislocation movement, which breaks away from the pinning of the Coriolis air mass and moves under the action of greater stress (Lüders belt) Lower yield point: The movement after breaking away from the dislocation is easier and the stress decreases.

Polymeric two-phase alloy: the size of the second phase particles and the matrix grains are of the same order of magnitude (the precipitates are mostly deformable)

Dispersed two-phase alloy: the second phase particles are finely and dispersedly distributed in the matrix grains (non-deformable)

1. Changes in microstructure

2. Substructural changes

3. Performance changes (work hardening)

4. Deformation texture

5. Residual stress

a. Low temperature recovery: point defects

b. Medium temperature recovery: dislocations and some point defects

c. High temperature recovery: dislocation

a. Nucleation

b.Grow up

The lowest temperature at which recrystallization begins during cold deformation

Influencing factors

a. Influence of deformation

b. Effect of annealing temperature

Spontaneous process; driving force: reducing its total interface energy

Influencing factors

The new grains of metals with deformed textures after recrystallization can have preferred orientations

Consistent with the original deformed texture: ① consistent; ② the original texture disappears and is replaced by a new texture; ③ the original texture disappears and no longer forms a new texture

Formation mechanism: directional growth theory (different orientations); directional nucleation theory (consistent)