What is the relationship between viscosity and plasticity in crystals?

[RPI_Quantum]

I was wondering what viscoplasticity is. I am familiar with viscoelasticity, but I heard the term viscoplasticity mentioned in an internet article the other day and I did not know what was meant by it.

Could anyone give me a general definition or a good link? I searched myself with a simple google search, but I could not seem to find anything helpful.

 

[PerennialII]

I was wondering what viscoplasticity is. I am familiar with viscoelasticity, but I heard the term viscoplasticity mentioned in an internet article the other day and I did not know what was meant by it.
Could anyone give me a general definition or a good link? I searched myself with a simple google search, but I could not seem to find anything helpful.

Hi RPI, a 'general' definition ...

usually viscoplasticity is used as a synonym for rate dependent plasticity when the strain rate is low, and with respect to metals the usual application is then creep deformation (in general high strain rate applications, dynamic events, do fall under the same principle category, but usually viscoplasticity is used to refer to time-dependent plastic creep response - but in principle the general definition is simply rate dependent plasticity). So "analogous" to your knowledge of viscoelasticity except with plastic deformations (with highly differing material models of course). For example with respect to creep typical viscoplastic models are the ones like the Power-law creep (Norton-Bailey), Hyperbolic creep law family, etc.

 

[Ruslan_Sharipov]

Viscosity and plasticity are separate phenomena

Look the following links for the nonlinear theory of plasticity in crystals incluiding the viscosity as a separate phenomenon:
http://arxiv.org/abs/cond-mat/0504180
http://arxiv.org/abs/math-ph/0502007
http://arxiv.org/abs/cond-mat/0411148
http://arxiv.org/abs/cond-mat/0410552
http://arxiv.org/abs/math-ph/0410006