Marie Bedel

Ecole Nationale Supérieure d'Arts et Métiers | ENSAM · Laboratoire Mécanique, Surfaces, Matériaux et Procédés (MSMP)

In aluminum low-pressure sand casting process, filling oscillations are observed when the metal front reaches a section change in a part. The effect of geometry on the filling oscillations is primary considered experimentally, including both mold cavity and filling system geometries. To highlight the geometric parameters impacting the oscillations,...

The molten metal flow under low-pressure filling was investigated both experimentally and numerically inside sand molds with different cross sections and different pressure ramps. The proposed fluid dynamics simulation predicts quantitatively the observed filling oscillations. An analytical model is developed to link the over-height with the geomet...

The sand mold 3D printing technologies enable the manufacturing of molds with great dimensional accuracy. However, the roughness of as-cast components is higher when cast in a 3D printed mold rather than in a traditional sand mold. Coating the inner cavity is an efficient solution but can be costly and, in the narrowest cavities, not achievable. Fi...

The macroscopic multiphase flow and the growth of the solidification microstructures in the mushy zone of a direct chill (DC) casting are closely coupled. These couplings are the key to the understanding of the formation of the macrosegregation and of the non-uniform microstructure of the casting. In the present paper we use a multiphase and multis...

Prediction of solidification defects, such as macrosegregation and inhomogeneous microstructures constitutes a key issue for the industry. The development of models of casting processes needs to account for several imbricated length scales and different physical phenomena. For example, the kinetics of the growth of microstructures needs to be coupl...

The impulse atomization process developed at the University of Alberta (Canada) enables metallic powders to be solidified with controlled process parameters and improved properties. In order to investigate the microstructure morphologies in droplets of Al- 4.5wt.%Cu alloys, three-dimensional reconstructions of several droplets are obtained by using...

The phenomena responsible for the formation of macrosegregations, and grain structures during solidification are closely intertwined. We present a model study of the formation of macrosegregation and grain structure in an industrial sized (350 mm thick) direct chill (DC) cast aluminum alloy slab. The modeling of these phenomena in DC casting is a c...

The microstructure morphology of Al-4.5wt.%Cu droplets formed by the Impulse Atomization technique is investigated. Three-dimensional reconstructions by synchrotron X- ray micro-tomography of several droplets reveal different morphologies in droplets of similar diameter and produced in the same batch. Moreover, microstructural features also indicat...

This paper reports on rapid solidification of Al-Cu alloys. A heterogeneous nucleation/growth model coupled with a thermal model of a falling droplet through a stagnant gas was developed. The primary undercooling as well as the number of nucleation points was compared with Al-Cu alloy droplets produced by Impulse Atomization (IA). Based on experime...

The mechanical properties of an alloy being related to its microstructure, the understanding of the mechanisms responsible for the grain structure formation in direct chill casting is crucial. However, the grain size prediction by modelling is difficult since a variety of multi-scale coupled phenomena have to be considered. Nucleation and growth of...

We investigate the impact of the convective transport of inoculant particles on the distribution of the final microstructure (grain size) in grain-refined aluminum-alloy castings. We carry out numerical simulations of a casting experiment, considering the solidification of an Al–22 wt.%Cu alloy inoculated with Al–Ti–B in a side-cooled 76 × 76 × 254...

The impulse atomization process developed at the University of Alberta (Canada) enables metallic powders to be solidified with well controlled process parameters. The inner microstructure of several droplets of Al–4.5 wt.%Cu alloy produced by this technique has been investigated by using both synchrotron X-ray micro-tomography and electron backscat...

The phenomena responsible for the formation of macrosegregations, and grain structures during solidification are closely intertwined. We present a model study of the formation of macrosegregation and grain structure in an industrial sized (350 mm thick) direct chill (DC) cast aluminum alloy extrusion ingot. The modeling of these phenomena in DC cas...

We investigate the impact of the nucleation law for nucleation on Al-Ti-B inoculant particles, of the motion of inoculant particles and of the motion of grains on the predicted macrosegregation and microstructure in a grain-refined Al-22 wt.% Cu alloy casting. We conduct the study by numerical simulations of a casting experiment in a side-cooled 76...

We study the effect of solidification kinetics, driven by local limited diffusion in the liquid, on macrosegregation. If the diffusion in the liquid surrounding a growing grain is slow, the local average liquid concentration is lower than the thermodynamic equilibrium concentration at the interface. The redistribution of solute by the flow of inter...

The phenomena responsible for the formation of macrosegregations, and grain structures during solidification are closely related. We present a model study of macrosegregation formation in an industrial sized (350 mm thick) direct chill (DC) cast aluminum alloy extrusion ingot. The modeling of these phenomena in DC casting is a challenging problem m...

The phenomena responsible for the formation of macrosegregations, and grain structures during solidification are closely intertwined. We present a model study of the formation of macrosegregation and grain structure in an industrial sized (350 mm thick) direct chill (DC) cast aluminum alloy extrusion ingot. The modeling of these phenomena in DC cas...

The grain structure formation in direct chill (DC) casting is directly linked to nucleation, which is generally promoted by inoculation. Inoculation prevents defects, but also modifies the physical properties by changing the microstructure. We studied the coupling of the nucleation on inoculant particles and the grain growth in the presence of melt...

We study the effect of solidification kinetics, driven by local limited diffusion in the liquid, on macrosegregation. If the diffusion in the liquid surrounding a growing grain is slow, the local average liquid concentration is lower than the thermodynamic equilibrium concentration at the interface. The redistribution of solute by the flow of inter...

The phenomena responsible for the formation of macrosegregations and grain structures during solidification are closely related. We present a model study of macrosegregation formation in an industrial sized (350 mm thick) direct chill (DC) cast aluminum alloy slab. The modeling of these phenomena in DC casting is a challenging problem mainly due to...

The phenomena responsible for the formation of macrosegregations, and grain structures during solidification are closely intertwined. We present a model study of the formation of macrosegregation and grain structure in an industrial sized (350 mm thick) direct chill (DC) cast aluminum alloy slab. The modeling of these phenomena in DC casting is a c...