nucleation

Dear colleagues  As fellows in fracture mechanics, you may be interested in these comments on a recent very nice Nature paper by the group of Jay Fineberg, making clever experiments to measure nucleation of small cracks in frictional interfaces of PMMA, and their propagation velocity during nucleation and later rapid acceleration.   Fineberg derives a threshold shear stress for nucleation which depends on the specimen width which seems new in fracture mechanics to me, but does not entirely convince me, see in the text.   If you have any comments please let me know, I would be glad to discus

by Oscar Lopez-Pamies, John E. Dolbow, Gilles A. Francfort, and Chris J. Larsen

Abstract

Homogeneous nucleation from aluminum (Al) melt was investigated by million-atom molecular dynamics (MD) simulations utilizing the second nearest neighbor modified embedded atom method (MEAM) potentials. The natural spontaneous homogenous nucleation from the Al melt was produced without any influence of pressure, free surface effects and impurities. Initially isothermal crystal nucleation from undercooled melt was studied at different constant temperatures, and later superheated Al melt was quenched with different cooling rates.

http://www.magnet.ubc.ca/wiki/images/5/5a/Abhijit_Mg2012.pdf

Deformation in metals and alloys is accompanied by high hardening rates and high dislocation 

content. Static annealing of deformed metals or forming operations at elevated temperatures can 

lead to static and dynamic recrystallization (SRX and DRX). The resultant texture and hence the 

properties of such a material are determined by the nucleation and growth of recrystallized grains 

The attached paper was recently published
in Applied Physics Letters. We show for the first time that Nucleation and
Condensation of Water can be spatially controlled. Such control of nucleation
phenomena and the fundamental findings discussed in the paper have implications
for the Energy and Water industry. The paper can be found at http://link.aip.org/link/?APL/95/094101/1