| | | | | | | webmail : intra-extra| Accès VPN| Accès IST| Contact | Français
First principles calculations of point, line and planar defects in metals
Christopher WOODWARD
Air Force Research Laboratory, Materials and Manufacturing Directorate Wright-Patterson Air Force Base, Ohio, USA
Tue, Nov. 18th 2008, 10:30
SRMP Bât 520 p.109, CEA-Saclay
Here we review property predictions for a variety of defects in metal alloys by means of density functional theory. The emphasis of this work is on defects that mediate or influence plastic deformation such as dislocations, solid solutions, and precipitates. The free energy of relevant point and planar defects are estimated from thermodynamic models based on these first principles results. For example, the site selection and density of ternary solutes in ordered intermetallics (e.g. Al3Sc+X) and the equilibrium profile of interfacial boundaries (IFB) in Al-Al3Sc are estimated using a lattice gas model appropriate for dilute levels of impurities. For Al-AL3Sc+Mg alloys impurity segregation of Mg to the Al side of the (100) IFB is predicted, a result recently verified by atom probe tomography. Alternatively, a cluster expansion method is used to study composition profiles and free energies of IFB's in Ni-Ni3Al. Finally, we have also developed methods for containing the strain field of isolated dislocations (i.e. line defects) in very small simulation cells. Using this technique we have studied the equilibrium strain field of dislocations in bcc (Mo, Ta, Fe), fcc (Al, Ir), and intermetallic alloys (L10 TiAl). We have evaluated solute dislocation interactions in Mo-X (X=Hf, Ta, Re, Os, Ir and Pt) and these interactions are used to inform a new model of solution hardening and softening at low temperatures. Recently, we have evaluated solute-edge dislocation interactions in Al-Mg alloys and differences between the first principles and continuum estimates of the Cottrell "atmosphere" are presented.
Contact : Luc BARBIER

 

Séminaire SRMP - Informations pratiques

Entrée sur le site du CEA de Saclay pour les séminaires SRMP

Afin de pouvoir entrer sur le site du CEA de Saclay veuillez adresser les données personnelles suivantes par courriel à :
(secrétariat) un avis d’entrée vous sera alors délivré :

 

Nom :

Prénom :

Date et lieu de naissance :

Nationalité :

Nom de l'employeur :

 

Ces informations doivent être envoyées au mieux deux jours avant la date du séminaire.>

Lors de votre venue vous devez vous présenter avec une carte d'identité ou un passeport en cours de validité. L'entrée sur le site se fait par l'entrée principale ou porte Nord (suivre le lien ci-dessous), un badge vous y sera remis. Demandez à l'accueil le Bât.520, ils vous renseigneront.
Les séminaires se déroulent au Bât. 520, pièce 109 (1er étage).
En cas de problème vous pouvez contacter le secrétariat au : 01 69 08 51 67


Formalities for entering the CEA Saclay site for SRMP seminars

To enter in CEA Saclay you need to send the following personal data to   (secretariat):

Informations utiles/Practical informations - Contact:

Informations:  Access to the CEA Saclay

 

Contact:

 

Last Name :

First Name :

Place and date of birth :

Nationality :

Employer Name :

These informations must be preferably sent at least two days before the seminar date.

 

When you come you must have a valid ID card or passport with you.

The entrance in CEA Saclay is through the main entrance or north entrance (see link below), a pass will be delivered. Ask at the “accueil” the path for the building 520. SRMP seminars take place in room 109 (first floor).

Any questions/troubles do not hesitate to contact our secretariat: 33 (0)1 01 69 08 51 67.


 

#38 - Last update : 11/02/2013

 

Retour en haut