Investigation of MAFAPAS processing parameters for producing dense nanostructured FeAl

2003

Determination of Zircaloy -4 Radiocristallographic Elastic Constants from Room Temperature to 300°C

2000

A new experimental apparatus, allowing the determination of radiocristallographic elastic constants (REC) as a function of the temperature is presented. The material studied the zirconium alloy Zircaloy-4, showing low elastic anisotropy, an isotropic treatment of the problem is possible. As a consequence, the classical sin 2 ψ method is used to determine the REC from room temperature to 300°C.

Investigation of mechanically activated field-activated pressure-assisted synthesis processing parameters for producing dense nanostructured FeAl

2003

The parameters of the mechanically activated field-activated pressure-assisted synthesis (MAFAPAS) process, which were recently developed and patented for producing dense nanostructured materials, were studied in the case of the B2-FeAl intermetallic. Based on x-ray diffraction (XRD) experiments, residual stresses XRD analysis, relative density measurement, and secondary-electron microscopic observations, the optimal synthesis conditions (time, current intensity, and pressure) were studied. Fe + Al powders were comilled in a specially designed planetary mill to obtain a mixture of reactants at the nanoscale without the formation of any product. The milled mixtures were then subjected to a h…

Study of stress effects in the oxidation of Zircaloy-4

2001

Abstract The oxidation of zirconium alloy Zy-4 is due to an anionic diffusion of oxygen leading to the formation of an oxide layer of zirconia. According to the Pilling and Bedworth ratio of the Zr/ZrO 2 system, the oxide scale is under compressive stresses. This stress state may play an important role during the corrosion process, from the phases as well as from the kinetics point of view. In order to better understand the eventual relationship between oxide phases, oxidation kinetics and stresses, an experimental apparatus was developed in our laboratory. It allows the application of external tensile stresses, in situ oxidation of the sample in controlled environment and X-ray diffraction…

Determination of single crystal elastic constants in textured polycrystalline materials: inverse approach coupling x-ray diffraction and self consist…

2004

La diffraction des rayons X couplee a l'utilisation d'un modele polycristallin (modele auto-coherent) est utilisee pour determiner les constantes d'elasticite monocristallines d'un materiau polycristallin texture. En effet, la connaissance du tenseur de rigidite elastique cijkl d'un solide est fondamentale pour les etudes s'attachant a la comprehension des proprietes mecaniques de la matiere (approches theoriques ou experimentales). Si, d'autres techniques permettent de determiner le tenseur d'elasticite d'un materiau (ultrasons par exemple), elles necessitent souvent l'utilisation d'un monocristal. Ceci n'est pas toujours realisable, en particulier pour des alliages de concentrations varia…

Understanding and Predicting Plutonium Alloys Aging: A Coupled Experimental and Theoretical Approach

2003

Understanding plutonium aging is a real challenge that requires developing very ambitious modeling and experiments. Examples of the different techniques developed and the physical values that can be reached are presented here.