Meaning
Strengthening of a metal through plastic deformation is caused by dislocation movements and accumulation within the crystal structure. This process of strain hardening increases the yield strength of the material but reduces its ductility. Manufacturing processes that stamp or bend chassis parts rely on this effect to increase structural rigidity.
Metal Forming
Bending aluminum sheet metal for electronic enclosures increases the strength of the formed corners. Because strain hardening occurs during the bending process, the finished bracket resists subsequent deflection better than the raw metal stock. This increased strength allows the use of thinner sheets to save weight, which is a major factor in mobile and aerospace designs.
It also demands precise control over the bend radius to ensure the sheet metal does not fracture.
Microscopic Effect
Dislocation density rises as the metal is worked, creating barriers to further dislocation movement. This microstructural strain hardening makes the material harder and more brittle at the bend zones. Engineers must monitor this change to prevent cracking in high-strain areas during assembly.
Die Integrity
Punching holes in brackets requires high force as the metal hardens. Uncontrolled strain hardening can cause tool wear and dimensional inaccuracies on the part edges. These effects are managed by periodically annealing the material.
