Thanks for the comment.

Indeed, grain boundaries represent a significant problem that needs to be addressed systematically. In other words, the problem requires analysisi on both micro- (atomistic) and meso-scale (continuum?). Interactions with diffusion, dislocation motion and boundary migration mechanisms are the key problems.

Regards.

Sinisa

Dear Professor Mesarovic,

Thanks for talking about this taopic, I just want to make some comment about grain boundary motion and behavior.

grain boundary has been studied more after the introduction of nanocrystalline metals that have high grain boundary volume fraction. The interesting behaviors of grain boundaries including migration under stress or thermal energy have been studied very well these years. I just mention some famous works in this field:

Coupling grain boundary motion to shear deformation, John W. Cahn, Yuri Mishin, Akira Suzuki, Acta Materialia, 2006.

http://www.sciencedirect.com/science/article/pii/S1359645406005313

Experimental observations of stress-driven grain boundary migration, T.J. Rupert, D.S. Gianola, Y. Gan, K.J. Hemker, Science, 2009.

http://science.sciencemag.org/content/326/5960/1686

and other works. Recently a few of interesting works addressed grain boundary description specifically phase transformation based on thermodynamics,

Thermodynamics of coherent interfaces under mechanical stresses I and II, T. Frolov, Y. Mishin, PRB, 2012.

http://journals.aps.org/prb/abstract/10.1103/PhysRevB.85.224106

http://journals.aps.org/prb/abstract/10.1103/PhysRevB.85.224107

structural phase transformations in metallic grain boundaries, T. Frolov, D.L. Olmsted, M. Asta, Y. Mishin, Nature Communications, 2013.

http://www.nature.com/articles/ncomms2919

Now I think it is the right time to address the grain boundary migration based on thermodynamic description. Since thermodynamics has the power to relate microscopic phenomena such as grain boundary migration to macroscopic properties such as temperature, pressure and volume and helps us to have a macroscopic interpretation of plasticity in interfaces.