The recrystallization temperature of a cold-worked metal can be lowered by_________________?
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Answer: D. all of the above
Explanation
The recrystallization temperature of a cold-worked metal can be significantly lowered through material purification. Grain refinement and prior plastic deformation also increase internal stored energy, facilitating earlier recrystallization during heating. All of these metallurgical factors contribute collectively to reducing the thermal threshold required for new unstressed grains to form. Cold working introduces high dislocation density within the crystal lattice, increasing the internal energy state of the metal. Recrystallization is the thermal process where deformed grains are replaced by new strain-free crystals upon heating. Metallurgical purity removes solute drag effects that normally impede grain boundary migration during the recrystallization phase.
Option A highlights metal purification but ignores the equally valid contributions of grain refinement and cold work. Option B mentions grain refinement correctly but overlooks the role of chemical purity in lowering recrystallization temperatures. Option C references low-temperature working which contributes to the stored strain energy driving subsequent recrystallization phenomena.
- Subject
- Engineering
- Category
- Mechanical Engineering
- Topic
- —
- Difficulty
- medium
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