What stress values go in the Hall-Petch equation?

[da_coolest]

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according to the equation what are the two stress related value that should be entered? (the value before the = and the value after = sing?




this is a silly question. but i couldn't find any answer and I am in a hurry!

Thanks in advance

 

[Mapes]

this is a silly question. but i couldn't find any answer and I am in a hurry!

http://en.wikipedia.org/wiki/Grain_boundary_strengthening#Hall-Petch_relationship". It took 0.61 seconds.

 

[pukb]

k and sigma0 are constant for a material and their values depend purely on the material.