EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

In the last decades, enormous progress has been made in understanding the physics of dendritic, cellular, eutectic and peritectic as well as columnar and equiaxed solidification of alloys. However, under productive conditions, melt convection and motion of crystals smear up local growth conditions such that for many cases predictions of the final microstructure might be unreliable. In this...

Abstract
Unidirectional solidification experiments were performed using a rotating magnetic field (RMF) to study the effect of the melt flow on the solidified micro-and mesostructure. In the case of one sample, the magnetic field changed between 5 and 35 mT. The experiments were performed with two temperature gradients (~10 K/mm and ~4 K/mm), and six different solid/liquid interface...

The experiments aimed to investigate the effect of stirring by Rotation Magnetic Field (RMF) on the solidified micro- and mesostructure of Al-12.6%Si alloy. The solidification experiments were performed in a Bridgman-type furnace in earth conditions at an average sample-movement velocity (vmov = 0.1 mm/s) and average temperature gradients (G = 6 K/mm) without stirring the melt as well as...

The formation of freckle defects in the presence of an external magnetic field is studied by combining in situ synchrotron imaging with numerical simulations. The formation, growth and motion of freckle channels during directional solidification are investigated in a Hele-Shaw cell for a low melting point Ga-In alloy. The solidification cell is placed in a permanent magnet system providing a...

Ductile cast iron is of increasing importance for transportation and renewable energy sectors. A critical factor for the mechanical characteristics of ductile iron castings is the morphology of the embedded graphite nodules which, under certain solidification conditions, degenerate and form irregular features, resulting in inferior mechanical properties. In situ time-resolved high-speed...

The standard types of graphite particles in cast iron are classified as spheroidal, compacted and lamellar graphite particles. The compacted graphite is considered as an intermediate shape between spheroidal and lamellar graphite. In spite of the many years of research, little is known about the physical phenomena leading to the evolution of compacted graphite (CG) within liquid melt during...

In-situ monitoring of solidification processes can provide key characteristics for solidification modeling when careful interpretation of the data is performed. X-radiography observation is a relatively fast method to collect data on nucleation, growth and solute field dynamics in thin binary alloys under varying gravity conditions. To get additional information on the three-dimensional...

Metallic melts can be undercooled significantly below their melting temperatures when containerless processed using electrostatic levitation. At these far from equilibrium conditions the system can exhibit dendritic growth.
Kobold et.al. [1] reported heat fronts of ten-fold symmetry for NiZr at high undercoolings. These fronts were in-situ observed by a high-speed camera, as locally released...

During metallurgical processes, gas bubbles can be observed to nucleate at different stages of the processing, and consequently interact with the microstructure. The present research on Al-Cu and Al-Ge alloys, showcases the interaction during solidification between these bubbles and the approaching solidification front through state of the art in situ X-radiography techniques and allows for...

By using of Al-20wt%Cu alloy, solidification experiments were performed by unidirectional solidification in our Bridgman-type furnace. A constant temperature gradient (~6 K/mm) and two different solid/liquid interface velocities (from 0,02 to 0,2 mm/s) was used. The sample movement velocity was suddenly increased during the solidification process.
The aim of our experiments was to...

Metallurgical technologies of the XXI century should possess the following characteristics simultaneously: (i) low cost and energy consumption, (ii) high strength, ductility and weldability of the manufactured product, (iii) commercial sustainability at low production volumes, (iv) flexibility of equipment for quick change to new product geometry and steel composition. The closest...

Flue gas recirculation (FGR) has been proposed as a process improvement for ferrosilicon production, with the aim of increasing the CO2 concentration in preparation for carbon capture and storage or use. By replacing cold ambient air with warm recirculated flue gas, the potential for energy recovery is also increased. Reducing the concentration of oxygen in the combustion air is also expected...

Due to climate change considerations and the rising costs for the emissions of carbon dioxide, the need for finding alternative reducing agents is becoming apparent. Hence, hydrogen is increasing-ly considered and is investigated in this paper. Through the use of hydrogen as a reducing agent for the production of metals, in this case secondary copper, inherent CO2 emissions associated to...

Aluminium machining swarfs constitute an economic ordeal for manufacturing companies. High volumes of swarfs are generated daily through machining and the companies need to pay for the removal and transport of this by-product. The swarfs are compacted in briquettes to reduce their volume and partially disposed of through large foundries or landfilled.
The main issues reported in literature...

Fe is a detrimental impurity element in secondary Al-Si cast alloys leading to the formation of primary, Fe-containing intermetallic particles, e.g. β-Al4.5FeSi, αh-Al7Fe2Si or αc-Al9(Mn,Fe)2Si1.8, which cause a decrease of castability and promote crack formation. The Fe content can principally be reduced by removal of the primary particles. Melt conditioning, i.e. melt treatments closely...

It is widely accepted that there is a need to create a digital twin of gas atomisation to aid development and increase the production and energy efficiency of the process. This talk will summarise research efforts to understand the gas flows in gas atomisation using experimentally validated computational fluid dynamics simulations. Such simulations are able to predict the profile of gas flow...

Ceramic particulate reinforced aluminium metal matrix nanocomposites (MMNCs) have been extensively developed for automotive and aerospace applications, due to their high-specific-strength. The ductility and toughness of the aluminium matrix combined with the strength and stiffness of the reinforcements manifests superior properties over the matrix. Both the ductility and toughness of the alloy...

The paper presents the results of research aimed at developing molding sand for manufacturing large-size iron castings using the Full Mold technology. Ultimately, the sand will be used to manufacture castings from a new type of ductile iron. Due to the specific properties of the castings, it was decided that the optimum sand should feature:
- appropriate shape and size of fresh sand/reclaim...

Thixomolding has emerged as environmental-friendly, technologically and economically competitive process for manufacturing lightweight components of magnesium alloys in consumer goods, sports, electronics and automotive industries. The beneficial process characteristics include comparatively low mold filling temperature and high injection pressure of the semisolid thixotropic metal slurry,...

Thermodynamic properties of phases and phase equilibria are the key to the analysis of pyrometallurgical processes and they enable to describe the limiting boundary conditions for metallurgical processes. The raw materials basis of non-ferrous metals needs an effective control of slag fluxing due to the unavoidable fact that the targeted metal values of, e.g., copper, nickel, lead and tin will...