Impact of the temperature and chemistry condition on the dissolution of alumina raft in electrolysis cells

Jonathan ALARIE¹, László I. KISS¹, Lukas DION¹, Sébastien GUÉRARD², Jean-François BILODEAU²

¹ GRIPS, Université du Québec à Chicoutimi, 555 Bd de l'Université, Chicoutimi, QC G7H 2B1

² Centre de recherche et de développement Ardiva, Rio Tinto, 1955 Mellon Boulevard, Jonquière, QC, G7S 4K8

The injection of alumina powder in electrolysis cells leads to the formation of alumina rafts that limits the solid-liquid contact needed for the dissolution of the powder. Accordingly, the migration of the dissolved alumina to the zone of reaction under the anode is delayed, leading to undesired events, such as the anode effect. Knowing that raft formation is unavoidable, an improved knowledge of the chemical and thermal conditions that favor the dissolution of those rafts is the best available path to optimize the operations strategy in real-time following changes in the process conditions. Such knowledge was acquired by conducting a parametric study on non-porous sintered alumina discs. Accordingly, the dissolution behavior of those discs is described by the Reynolds, Schmidt, and Sherwood numbers to compare the influence of the input parameters. Results show that the chemical and thermal conditions modify the flow around the sample and the diffusion coefficient of the alumina. Namely, a correlation between the cryolite ratio and the activation energy required by diffusion has been found. Using these inputs, new opportunities for an improved control strategy are foreseen for the aluminum industry.

Experimental characterization of the resistance of open aluminium sections through the Overall Interaction Concept

Sahar DAHBOUL¹, Nicolas BOISSONNADE¹, Pampa DEY¹, Mario FAFARD¹, Liya LI¹, Prachi VERMA¹

¹ Department of Civil and Water Engineering, Laval University, 1065 Av. de la Médecine, Quebec, QC, G1V 0A6

A high strength-to-weight ratio, excellent durability and corrosion resistance, formability and recyclability make aluminium an excellent candidate for sustainable constructions. Regardless of these advantages, aluminium is yet to be widely accepted as a material of choice for structural members, mainly due to (i) the lack of knowledge towards its mechanical behavior under different loading conditions and to (ii) limitations in current design guidelines. This research is aimed at better understanding the structural resistance of aluminium sections and members and at developing a novel design approach based on the principles of the Overall Interaction Concept (O.I.C.), that will eventually lead to a more cost-effective design. In this respect, an extensive experimental program was performed to investigate the buckling behavior of aluminum extrusions with different section shapes subjected to compression. The present presentation will focus specifically on the response of I-sections. A non-linear finite element model was developed within ABAQUS, which was further validated against experimental data. These models were then used extensively to collect a large amount of reference results, and comparisons with resistance predictions from well-known design standards have been made. The performance of the newly developed, O.I.C.-based design method has been assessed based on the numerical and experimental observations.

Development of aluminum-based feedstock for 3D printing

Dorian DELBERGUE¹, Abdelberi CHANDOUL¹, Jacob BERNIER¹, Roger PELLETIER², Louis-Philippe LEFEBVRE², Yannig THOMAS², Vincent DEMERS¹

¹ Département génie mécanique, École de technologie supérieure, 1100 Rue Notre Dame O, Montréal, QC, H3C 1K3

² Conseil National de Recherche du Canada, 75 Boulevard de Mortagne, Boucherville, QC, J4B 6Y4

Material extrusion is an additive manufacturing process widely used with plastics, however it has been recently developed for metals. A mixture of sacrificial polymeric binder is highly-filled with metallic powder, similarly to those developed for metal injection molding, and then printed layer by layer to shape the green part. The printed part is then debound and sintered to remove the binder and densify the final metallic part. The quantity of defects, such as pores, can be minimized by controlling the viscosity of the powder-binder mixture, several factors of which come into play, namely the particle size distribution and the binder formulation. Although several steels and superalloys are already printable by laser powder bed fusion approaches, aluminum alloys are recognized to be difficult to manufacture with these approaches since they are highly reflective and subject to surface oxidation. This study presents the development of aluminum-based (AlSi10Mg) feedstocks for 3D printing by material extrusion.

Titre de la conférence: Degree of sophistication required for the dynamic modelling of steel-aluminium hybrid bridge with extruded aluminium deck

Influence of heat treatment on microstructure and mechanical properties of Al40Si fabricated by AM

An Fu¹, Satish Kumar Tumulu¹, Jaskaranpal Singh Dhillon¹, Mathieu Brochu¹

¹ Department of Mining and Materials Engineering, McGill University, Montreal, Quebec, H3A 0C5, Canada

Hypereutectic Al-Si alloys have wide industrial applications such as aircraft, automobile, electronic packaging, as driven by their high specific strength, desired wear and corrosion resistance, high thermal conductivity, low coefficient of thermal expansion and so on. The mechanical properties of hypereutectic Al-Si alloys can be considerably enhanced by Additive Manufacturing (AM), in which microstructure refinement, increased solid solubility of strengthening elements, desired grain morphology can be achieved by rapid solidification. Meanwhile, the microstructure and mechanical performance of hypereutectic Al-Si can be further modified by heat treatment. In this study, Al-40Si samples with different geometries are fabricated by Laser Powder Bed Fusion (LPBF) using optimized parameters, the as-built samples are heat treated at different temperatures and durations. A series of microstructure characterizations and mechanical tests are performed on as-built and heat-treated samples, in order to systematically investigate the effect of heat treatment on microstructure and mechanical properties of Al-40Si samples.