Annealing steel and aluminum alloys primarily results in which effect(s)?

• A. Increasing hardness
• B. Decreasing internal stresses and softening of the metal
• C. Increasing brittleness
• D. No change

Answer: (D)

Annealing softens the metal and relieves internal stresses by allowing the crystal structure to rearrange and dislocations to reorganize or annihilate. When steel or aluminum alloys are heated to a suitable temperature and held, followed by slow cooling, the material becomes more ductile and easier to form, with a noticeable drop in hardness and strength and a reduction in residual stresses. This is the primary outcome of the process. Options suggesting increased hardness, increased brittleness, or no change don’t match what annealing accomplishes.