A field theory of dislocation mechanics and plasticity is illustrated through new results at the nano, meso, and macro scales. Specifically, dislocation nucleation, the occurrence of wave-type response in quasi-static plasticity, and a jump condition at material interfaces and its implications for analysis of deformation localization are discussed.
We are pleased to announce Dislocations 2008, an international conference on the fundamentals of plastic deformation and other physical phenomena where the dislocations play pivotal roles. The conference will take place on October 13-17, 2008 at the Gold Coast Hotel, Hong Kong, China. More information about the Dislocations 2008 conference can be found at the following web site:
A PhD position is available for a thesis with SKF Aerospace France in the Laboratoire Génie de Production - Ecole Nationale d'Ingénieurs de Tarbes - France
Detailled subject (in French) can be found at : http://pantale.free.fr
Starting date October 2007
CV+letter can be send until September 8th 2007 to : Olivier.Pantale [at] enit.fr
Our paper on the Mechanical threshold stress (MTS) model for 6061-T6 aluminum has been accepted by JoMMS. There are several things of interest in the paper:
1) The use of a phonon drag model to predict the sharp increase in flow stress at strain rates above 10,000 /s. This behavior is seen in a number of materials and is hard to fit using standard power law plasticity models. Our model does a good job in this regard.
Does any one knows a good reference about lath martensite?
Why we see the retained austenite? why doesn't it transformto martensite? What's its effect on the phase transformation? Does the plasticity change the morphology of the transfromation? How about the speed of the transfromation? When should we expect to see the lath martensite? What's the effect of the diagonal terms in the transformation matrix? What's the effect of the shear components? Is there any difference between 2d and 3d simulations, and which one is more realistic?
Does any one knows a good reference about lath martensite?
Why we see the retained austenite? why doesn't it transformto martensite? What's its effect on the phase transformation? Does the plasticity change the morphology of the transfromation? How about the speed of the transfromation? When should we expect to see the lath martensite? What's the effect of the diagonal terms in the transformation matrix? What's the effect of the shear components? Is there any difference between 2d and 3d simulations, and which one is more realistic?
I have attached a copy of my McMat07 talk below. The talk is about a modified mechanical threshold stress (Follansbee-Kocks) model that can be used for strain rates > 1000 /s and high homologous temperatures. In the model, the pressure dependence of the flow stress arises from the pressure dependence of the shear modulus. Even after using the most accurate models for the shear modulus (and the melting temperature) we find that the pressure sensitivity of the flow stress is underestimated by our model (by quite a bit).
