A: Physical and chemical properties.
1) Density. After cold deformation, the density of aluminum is reduced due to defects such as microcracks or macroscopic cracks and cracks in the crystal and between the crystals.
2) Resistance. The destruction of intergranular materials causes direct contact of crystal grains, ordering of crystal grains, intergranular and intragranular cracking of aluminum profiles, etc., all of which have a significant influence on the change of electrical resistance. The first two reduce the resistance as the degree of deformation increases, while the latter is the opposite.
3) Chemical stability. After cold deformation, the material can be increased in height, making its chemical properties more unstable and susceptible to corrosion, especially stress corrosion.
 |  |
B: Mechanical properties.
After cold deformation of aluminum, due to intragranular and intergranular damage, the lattice is distorted and a second type of residual stress occurs, which causes the plasticity index to drop sharply, and may be close to a completely brittle state in the limit state. On the other hand, due to lattice distortion, increased dislocations, elongated grains and substructures, the aluminum profile greatly increases the strength index, that is, the work hardening phenomenon occurs.
C: Structure and anisotropy
After the large cold deformation of the aluminum material, the material exhibits anisotropy due to the texture. For example, aluminum alloy sheets are prone to significant ear formation during deep drawing. Processing conditions should be reasonably controlled to take advantage of the beneficial aspects of texture and anisotropy while avoiding or eliminating its disadvantages.
