Influence of cooling rates on temperatures phase transitions and on microstructure of aluminium alloy EN AW‐5083

Abstract

The casting of different forms and dimensions of aluminium alloy EN WA-5083 test samples and the usage of different types of mould materials resulted in achieving different cooling rates of samples. The methods used were simple thermal analysis, using casting into a measuring cell made by the Croning process and using casting into a cone-shaped measuring cell, as well as simultaneous thermal analysis using the method of differential scanning calorimetry. Significant temperature phase transitions and times of solidification were determined, and the dependence model of the solidification time on the sample cooling rate was obtained. Determining the mean number of grains per unit area on samples after having performed the simple thermal analysis and differential scanning calorimetry makes it possible to develop a dependence model of the mean number of grains per unit area on the cooling rate. These models are the basis for carrying out numerical simulations of solidification and microstructure development in the cone-shaped measuring cell, and the comparison of the distribution of the mean number of grains per unit area obtained by simulation with the one obtained experimentally. The obtained results represent a part of the preliminary tests of the microstructure development of industrially cast ingots of EN AW-5083 alloy depending on the local ingot cooling rate.Keywords: EN AW-5083 aluminium alloy / numerical simulation / thermal analysis methods / mean number of grains per unit area / Beim Gießen verschiedener Versuchsmuster mit unterschiedlichen Formen und Größen der Aluminiumlegierung EN WA-5083 und Verwenden verschiedener Formstofftypen, wurden unterschiedliche Abkühlgeschwindigkeiten festgestellt. Dabei wurde die Methode der einfachen Thermalanalyse angewendet, die beim Gießen in eine Messzelle einmal mit dem Croning-Verfahren hergestellt wurde und einmal in eine kegelförmige Messzelle gegossen wurde, samt gleichzeitiger Thermalanalyse mit der Methode der differenzierten Wärmemessung. Dabei wurden die Temperaturphasenübergänge und Zeiten bis zur Erstarrung ermittelt sowie das Zeit-Modell in Abhängigkeit der Abkühlgeschwindigkeit bis zur Erstarrung der Versuchsprobe ermittelt. Durch die Bestimmung des Mittelwertes der Anzahl der Körner pro Fläche auf der Versuchsprobe nach der durchgeführten einfachen Thermalanalyse und der Methode der differenzierten Wärmemessung, kann ein Abhängigkeitsmodell des Mittelwertes der Anzahl der Körner pro Fläche über die Abkühlgeschwindigkeit erstellt werden. Diese Modelle sind die Basis, um die numerische Simulation des Festwerdens und die Mikrostruktur-Entwicklung in der kegelförmigen messenden Zelle, samt der Simulation des Vergleichs der Verbreitung des Mittelwertes der Anzahl von Körnern pro Fläche zu erlangen. Die erhaltenen Ergebnisse repräsentieren einen Teil der Forschung der Mikrostruktur-Entwicklung beim industriellen Gießen von Blöcken der Legierung EN AW-5083 in Abhängigkeit der lokalen Abkühlgeschwindigkeit der Blöcke.Schlüsselwörter: EN AW-5083 Aluminiumlegierung /...

Galvanic corrosion of aluminum wrought alloys in integral hybrid components with carbon fiber reinforced plastics (CFRP) and titanium

“…Additionally, irregular intermetallic phases (2) with a size up to 5 μm were found. Equilibrium solidification of EN AW‐5083 proceeds from α‐aluminum to Al 6 Mn and Mg 2 Si, Al 8 Mg 5 , and Al 3 Fe precipitate under the solidus . Thus, the observed precipitations inside the grains are mainly due to Al 6 Mn.…”

“…Thus, the observed precipitations inside the grains are mainly due to Al 6 Mn. The pearl‐string‐like patterns of particles at the grain boundaries are probably due to Al 8 Mg 5 , which is known to precipitate preferentially at the grain boundaries …”

“…It finds applications in ship building, automobile and aircraft structures, tank containers, unfired welded pressure vessels, cryogenic applications, transmission towers, drilling rigs, transportation equipment, missile components, and armor plates. In many of these applications, the welded structures are exposed to aqueous environments throughout their lifetimes …”

Scanning Electrochemical Microscopy (SECM) Investigation of 3D Printed Parts Produced by CMT Welding Technology

“…AlMg4.5Mn0.7 (5083 aluminium) alloy is a popular commodity in different industrial applications owing to its favourable properties: excellent corrosion resistance behaviour, the highest strength among non‐heat treatable Al alloys, high ductility and good weldability . Several papers and PhD theses were written in the theme of corrosion of this material .…”

“…The cooling rate of alloys can strongly affect the size of crystals, grains and phases of intermetallic compounds formed during solidification. In case of faster cooling rate smaller ones with finer distribution or smaller quantity are formed .…”