a b s t r a c tIn this paper, a simple but realistic approach is presented to predict the as-quenched residual stress distribution in thick 7xxx aluminium alloy plates. Instead of modelling precipitation that occurs during quenching, a thermo-mechanical model is used whose parameters are identified using a limited number of tensile tests achieved after representative interrupted cooling paths in a Gleeble machine. The material behaviour law accounts for recovery at high temperature in a simple way and neglects the Bauschinger effect as suggested by a dedicated experiment. The results of this simple approach are compared to residual stress measurements in plates of different thicknesses for two different 7xxx alloys, AA7449 and AA7040.

This series of articles on hydride embrittlement effects in ZIRCALOYs consists of three parts. In Part II, the morphology of hydrides in two ZIRCALOYs has been examined at different magnifications and by different techniques (scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD)). The purpose is to establish the correlation between the hydride morphology and the microstructure of the ZIRCALOYs as a function of their pre-heat treatment and their hydrogen content. It was found that in these alloys microstructure has a very significant effect on the size, the stacking pattern, and the location of hydrides. The hydride morphology and its evolution with increasing hydrogen content was not the same in the stress-relieved annealed (SRA) and the recrystallized ZIRCALOYs. These observations were then correlated with the damage mechanisms of the hydrided ZIRCALOYs. Part I, concerned with the general influence of hydride on the mechanical properties of ZIRCALOYs and the damage and fracture mechanisms. Part III, on the other hand, discusses the mechanical properties of the hydrides themselves under the influence of several parameters.

This series of articles on hydride embrittlement effect in ZIRCALOYs consists of three parts. Part I is concerned with the general influence of hydride on the mechanical properties of ZIRCALOYs at two temperatures (20 ЊC and 300 ЊC) and for hydrogen content up to 4500 ppm. The damage and fracture mechanisms were investigated by scanning electron microscopy (SEM) fracture surfaces and profiles observations. Special attention was paid to better understanding the ductile-brittle transition as a function of the hydrogen content at two temperatures. The macroscopical behavior of the hydrided ZIRCALOYs was then correlated to the damage and fracture mechanisms. In Part II, the morphology and crystallographic structure of hydrides in two ZIRCALOYs is examined at different magnifications and by different techniques (SEM, transmission electron microscopy (TEM), and X-ray diffraction) as a function of their pre-heat treatment and their hydrogen content. Part III, on the other hand, discusses the mechanical properties of the hydrides under the influence of several parameters based mainly on the SEM in-situ observations and the mechanical modeling.

This series of articles on the hydride embrittlement effect in ZIRCALOYs consists of three parts. Part III deals with the mechanical properties of some hydrides in some ZIRCALOYs at two temperatures (20 ЊC and 300 ЊC). The damage and fracture mechanisms were investigated by SEM in-situ testing. Based on the scanning electron microscopy (SEM) in-situ observations and the mechanical modeling, the mechanical behavior of hydrides confined within a matrix was determined. The hydrides can undergo significant plastic deformation under certain conditions. They have higher strength than the surrounding ZIRCALOY matrix. The radiation effect on hydrided ZIRCALOYs and the combined effect were also discussed. Part I is concerned with the general influence of hydrides on the mechanical properties and damage and fracture mechanisms of ZIRCALOYs at two temperatures (20 ЊC and 300 ЊC) and for hydrogen content up to 4500 ppm. In Part II, the morphology and crystallographic structure of hydrides in two ZIRCALOYs are examined at different magnifications and by different techniques (SEM, transmission electron microscopy (TEM), and X-ray diffraction) as a function of their pre-heat treatment and their hydrogen content.

International audienceDuring the machining of thick, large and complex aluminium parts, the redistribution of initial residual stresses is the main reason for machining errors such as dimensional variations and the post-machining distortions. These errors can lead to the rejection of the parts or to additional conforming operations increasing production costs. It is therefore a requirement to predict potential geometrical and dimensional errors resulting from a given machining process plan and in taking into consideration the redistribution of the residual stresses. A specific finite element tool which allows to predict the behaviour of the workpiece during machining due to its changing geometry and to fixture-workpiece contacts has been developed. This numerical tool uses a material removal approach which enables to simulate the machining of parts with complex geometries. In order to deal with industrial problems this numerical tool has been developed for parallel computing, allowing the study of parts with large dimensions. In this paper, the approach developed to predict the machining quality is presented. First, the layer removal method used to determine the initial residual stress profiles of an AIRWAREⓇ 2050-T84 alloy rolled plate is introduced. Experimental results obtained are analysed and the same layer removal method is simulated to validate the residual stress profiles and to test the accuracy of the developed numerical tool. The machining of a part taken from this rolled plate is then performed (experimentally and numerically). The machining quality obtained is compared, showing a good agreement, thus validating the numerical tool and the developed approach. This study also demonstrates the importance of taking into account the mechanical behaviour of the workpiece due to the redistribution of the initial residual stresses during machining when defining a machining process plan