Test Sample's Performance in the Annealing Process - Assignment Example

The maximum value of hardness was obtained at a 70% reduction in area.

(a) What property must be exceeded for rolling to successfully change a material shape? (4%)
Give the reason for your answer.

The annealing process affects on mechanical properties of the sample’s test strain properties. The material loses its ductility during the cold rolling process. The Anneal strengthening effect or toughness of the material under investigation (copper) increases in the degree of prior cold work and the corresponding annealing.

(b) How would you expect the grain structure of the copper to change during the rolling process?
The ability of crystalline material to plastically deform depends on the ability for dislocation movement within copper. When the movement of dislocations is impeded, the material is strengthened. This is achieved through several ways such as;

• Control of the grain size or reducing continuity of atomic planes
• Strain hardening is achieved by creating and tangling dislocations and
• Alloying which entails the introduction of point defects and more grains to control dislocation

Strain hardening work-hardening or cold working is a process that makes copper harder and stronger through plastic deformation. As it is plastically deformed, dislocations move as additional dislocations are produced. As dislocation within the material increases, the grains interact and become pinned or tangled. As a result, there is decreased grain mobility of dislocations as the material is strengthened.

(c) Describe what is happening to the grains, grain boundaries, and dislocations during the
cold rolling process. Note, that the starting copper does not have porosity and therefore the
copper does not get denser nor do the atoms or grains get closer together. (4%)

Ductility increases with the grain size, as the strength decreases. Atomic diffusion occurs as temperature increases and it releases internal strain energy. Since atoms are not fixed in a position but move once they have enough energy to break their bonds, diffusion increases rapidly with the increase in temperature. This allows the atoms to move to unrestrained positions and recover a normal position in the lattice structure. This is the recovery phase and leads to an adjustment of strain.

(d) Investigate similar data for copper C 11000

In the annealing process, the test sample was performed in a 1000ºC capacity furnace. It was observed that the hardness of the copper sample increased with a gradual increase in the reduction in cross-sectional area. This is due to strain hardening. The maximum value of hardness was obtained at 117HB 40% reduction in area.

(e) By investigating published data for different levels of cold working suggest how the
reduction of thickness affects various mechanical and physical properties. (6%)


Understanding mechanical deformation properties ensures efficient stress-relieving procedures. The thickness of the material affects the hardness of the material. It is observed from the experiment that a reduction in the cross-sectional area of the material leads to the hardness of the copper. This is due to grain dislocation that occurs as the material gets exposed to reduced cross-sectional area (ASM International Handbook Desk Edition 56).
(f) What material property limits the amount of reduction possible, giving your reasons? (4%)
Ductility limits the possible amount of reduction since the grain size of the material reaches its probable limit of expansion and the ability of the movement of the free atoms is encouraged.