Publications de Jean-Marie Drezet

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Advancements in analyzing iron archaeological artifacts are helpful in many applications, i.e., elucidating corrosion phenomena experienced by nuclear waste repositories and lifetime prediction of still-buried objects, such as pipelines. This paper investigates the corrosion state of iron-based archaeological objects through bimodal neutron and X-ray computed tomography, SEM-EDX analysis, and Raman spectroscopy. The nail BdC2, excavated from the archaeological site Bois de Châtel in Switzerland, is used as

The appearance of hot tears, a very severe defect in castings, is a major limitation to the production of foundry cast parts and to the productivity of continuous casting processes such as the direct chill casting of aluminum alloys. As an example, the casting speed of the direct chill casting of billets is limited for some aluminum alloys because of their high propensity to develop hot tears, which initiate at non-zero liquid fraction at the bottom of the sump. In order to predict the occurrence of hot tea

During solidification of metallic alloys, coalescence corresponds to the formation of solid bridges between grains when both solid and liquid phases are percolated. As such, it represents a key transition with respect to the mechanical behaviour of solidif ...

Hot tear is one of the most serious defect which a casting can suffer. It represents a major limitation to the production of foundry cast parts and to the productivity of continuous casting processes such as the direct chiil casting of aluminium alloys. As an exemple, the starting phase of the direct chili casting process remains particularly critical for some aluminium alloys because of their high propensity to develop either hot tears which initiate at non zero liquid fraction, or cold cracks which nuclea

Temperatures measurements during flame cutting of a thick steel plate and measurements of the extension of the fusion and heat affected zones and Vickers hardness after cutting have been performed. Additionally, a 3-D thermal model for simulation of flame- ...

Analysis of the deflection of a circular membrane under differential pressure (bulge test) is a well-known method of determining the elastic properties of thin films. However, analytical models always suffer from simplifying hypotheses. In this study we present a new approach, based on numerical modeling, to interpret pressure-deflection curves. By adjusting Young’s modulus and Poisson’s ratio in the simulation program, it is possible to reproduce the experimental curves faithfully. The method was successfu

The deformation and the temperature field evolution within direct chill (DC) and electromagnetic (EM) cast aluminum ingots have been measured in-situ using a simple experimental set-up. The deformation of the cross section of the cold ingots has also been characterized as a function of the casting speed, alloy composition and inoculation condition. The pull-in of the lateral rolling faces has been found to occur in two sequences for DC cast ingots whereas that associated with EMC was continuous. The pull-in

As a necessary step toward the quantitative prediction of hot tearing defects, a three-dimensional stress–strain simulation based on a combined finite element (FE)/discrete element method (DEM) has been developed that is capable of predicting the mechanica ...

In 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 who ...

The presence of thermally induced residual stresses, created during the industrial direct chill (DC) casting process of aluminum alloys, can cause both significant safety concerns and the formation of defects during downstream processing. Although numerica ...

Stress relief treatment before machining and sawing aluminium direct chill cast products is required to avoid uncontrolled distortion, crack formation and significant safety concerns due to the presence of thermally induced residual stresses created during ...

This paper is devoted to the experimental and numerical assessment of residual stresses created by welding in the region surrounding the weld toe of tubular K-shaped joints (i.e. region most sensitive to fatigue cracking). Neutron-diffraction measurements ...

In the current trend toward thicker aluminium plates, a major concern is the stress build-up during quenching which causes distortions during machining. Indeed, cooling rates are not high enough, especially at the core of such thick plates, to prevent any ...

Hot tearing, a severe defect occurring during solidification, is the conjunction of tensile stresses which are transmitted to the mushy zone by the coherent solid underneath and of an insufficient liquid feeding to compensate for the volumetric change. In most recent hot tearing criteria, one of the critical issues is the definition of a coherency point which, in low-concentration alloys, corresponds to the bridging or coalescence of the primary phase. A coalescence model has been developed recently using t

The deformation and the temperature field evolution within direct chiil (DC) and electromagnetic (EM) cast aluminum ingots have been measured in-situ using a simple experimental set-up. The deformation of the cross section of the cold ingots bas also been characterized as a function of the casting speed, alloy composition and inoculation condition. The pull-in of the lateral rolling faces has been found to occur in two sequences for DC cast ingots whereas that associated with EMC was continuous. The pull-in

Hot tear formation has been observed during the solidification of a succinonitrile–acetone (SCN-acetone) alloy by pulling the columnar dendrites in the transverse direction with a stick. It is observed that the cracking of the mushy zone (hot tears) always occurs at grain boundaries. At low volume fraction of solid, the opening can be compensated for by leanersolute interdendritic liquid (i.e., “healed” hot tears). At higher volume fraction of solid, hot tears directly nucleate in the interdendritic liquid

In order to quantify the cooling conditions undergone by an ingot during direct-chill (DC) casting, thermocouples were immersed in the liquid pool and consequently entrapped in the solid, thus monitoring the temperature of the metal during its descent. Assuming steady-state thermal conditions, the time-dependent temperatures measured by these thermocouples were then converted into spacedependent temperature profiles. These values were the input of a Maximum A Posteriori (MAP) inverse method described by Rap

In the fabrication of heat-treatable aluminum parts such as AA2618 compressor impellers for turbochargers, solutionizing and quenching are key steps to obtain the required mechanical characteristics. Fast quenching is necessary to avoid coarse precipitatio ...

During solidification of metallic alloys, coalescence leads to the formation of solid bridges between grains or grain clusters when both solid and liquid phases are percolated. As such, it represents a key transition with respect to the mechanical behavior ...

Thermally-induced residual stresses, generated during the industrial Direct Chill casting process of aluminum alloys, can cause both significant safety concerns as well as the formation of defects during down-stream processing. Although these thermally ind ...

Jean-Marie Drezet

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Future from the Past: Long-Term Corrosion of Iron Analyzed Using Bimodal Neutron and X-ray CT

Prediction of Hot Tears in DC-Cast Aluminum Billets

In situ X-ray Diffraction during Casting: Study of Hot Tearing in Al-Zn alloys

Validation of a new hot tearing criterion using the ring mould test

Experimental and numerical characterisation of heat flow during flame cutting of thick steel plates

A new interpretation of bulge test measurements using numerical simulation

Thermomechanical Effects during Direct Chill and Electromagnetic Casting of Aluminum Alloys Part I : Experimental Investigation

Simulation of Semi-Solid Material Mechanical Behavior Using a Combined Discrete/Finite Element Method

Quench induced residual stress prediction in heat treatable 7xxx aluminium alloy thick plates using Gleeble interrupted quench tests

As-Cast Residual Stresses in an Aluminum Alloy AA6063 Billet: Neutron Diffraction Measurements and Finite Element Modeling

Stored elastic energy in aluminium alloy AA 6063 billets: residual stress measurements and thermomechanical modelling

Numerical modelling and experimental investigation on welding residual stresses in large-scale tubular K-joints

INTERNAL STRESS GENERATION DURING QUENCHING OF THICK HEAT TREATABLE ALUMINIUM ALLOYS

HOW DOES COALESCENCE OF DENDRITE ARMS OR GRAINS INFLUENCE HOT TEARING ?

Thermomechanical Effects during Direct Chill and Electromagnetic Casting of Aluminum Alloys. Part I : Experimental Investigation

Hot Tear formation and coalescence observations in organic alloys

Determination of thermophysical properties and boundary conditions of DC cast aluminum alloys using inverse methods

Quench-Induced Stresses in AA2618 Forgings for Impellers: A Multiphysics and Multiscale Problem

Measurement of Mechanical Coherency Temperature and Solid Volume Fraction in Al-Zn Alloys Using In Situ X-ray Diffraction During Casting

Residual Stresses in DC cast Aluminum Billet: Neutron Diffraction Measurements and Thermomechanical Modeling