Does Work Hardening Create Smaller Crystal Grains?

In summary, work hardening is a process that involves subjecting a metal to repeated mechanical stress, resulting in smaller and more numerous crystal grains. While it typically leads to smaller grains, the final size depends on factors such as initial grain size and amount of strain. Smaller grain size has various benefits including increased strength, hardness, and resistance to corrosion and wear. Work hardening can be partially reversed through annealing, but the material will still retain some of its effects.
  • #1
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This might be more of a simple engineering question, but does work hardening (cold worked) of say a metal create smaller, more numerous crystal grains (and thus, more grain boundaries)? or does it just create dislocations in the crystal?
 
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  • #2
That's a good question. My understanding is that work hardening creates numerous dislocation lines, which over the course of treatment tangle and have the effect of increasing the strength of the material

http://en.wikipedia.org/wiki/Work_hardening

Supposedly, vintage cymbals have a "special sound" from work hardening- caused by being struck for 30+ years.
 

1. What is work hardening?

Work hardening is a process in which a metal is subjected to repeated mechanical stress, causing dislocations within the crystal structure. This results in an increase in the material's strength and hardness.

2. How does work hardening affect crystal grains?

Work hardening causes the crystal grains in a metal to become smaller and more numerous. This is because as the material is strained, the dislocations within the crystal structure become tangled and create barriers, preventing further movement and causing the grains to break into smaller pieces.

3. Does work hardening always result in smaller crystal grains?

No, while work hardening typically results in smaller crystal grains, the final grain size also depends on factors such as the initial grain size, type of metal, and amount of strain applied. In some cases, work hardening may not significantly affect the grain size.

4. What are the benefits of smaller crystal grains?

Smaller crystal grains have a number of benefits, including increased strength, hardness, and toughness. They also have improved resistance to corrosion and wear. Additionally, smaller grains can lead to a more uniform and consistent material, making it easier to process and manufacture.

5. Can work hardening be reversed?

Work hardening can be partially reversed through processes such as annealing, which involves heating the material to a high temperature and then slowly cooling it. This allows the dislocations to rearrange and the grain size to increase. However, the material will still retain some of the effects of work hardening, such as increased strength and hardness.

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