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Are there stress and strain graphs for different crystal structures?

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- Thread starter darkelf
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Are there stress and strain graphs for different crystal structures?

- #2

Mapes

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Mapes

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OK, I think I know what you mean. See http://books.google.com/books?id=8r...0&ei=l1xBSfroKZS6ygS80IX-DQ&client=firefox-a" for the stress-strain relationship in an fcc single crystal. Taylor modeled the strength increase due to dislocation interactions, also known as work hardening or forest hardening, which is shown in stage II of the graph.

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Thanks Mapes,

He had an equation as well didnt he?

He had an equation as well didnt he?

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[tex]\Delta \tau\propto Gb\rho^{1/2}[/tex]?

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Sorry about the way the equation is

T= Shear stress

To = critical resolved stress

K = constant

G = shear strain

Can a graph for f.c.c be ploted from this equation?

- #10

Mapes

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[tex]\tau=\tau_0+KGb\rho^{1/2}[/tex]

which is equivalent to what I have above; the increase in shear strength [itex]\tau[/itex] is proportional to the square root of the dislocation density [itex]\rho[/itex]. Here's how you would plot the strength vs. dislocation density for a specific fcc sample:

1) As a reference point, experimentally measure the shear strength [itex]\tau[/itex] and the dislocation density [itex]\rho[/itex] of the sample.

2) Look up the shear modulus

3) Calculate the Burgers vector

4) From (1), (2), and (3), calculate the constants

5) Plot [itex] \tau=\tau_0+KGb\rho^{1/2}[/itex].

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Mapes

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- Description of a concept

- Formula

- Graph of an idealized relationship

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- #13

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sorry about that Mapes, just sent you a PM with the problem.

Thanks

Thanks

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