Production of π-AlMgSiFe Crystals
-
Christian J. Simensen
Abstract
Large crystals of π-AlMgSiFe have been grown in a molten aluminium alloy of Al-17.6 wt.% Si-7.6 wt.% Mg-1.0 wt.% Fe on the basis of information obtained through thermodynamic calculations, differential thermal analysis and micro-structure investigations. The π-crystals have been separated from the metal matrix by dissolving the alloy in butanol. X-ray diffraction and microprobe analysis of the phase reveal that it is hexagonal with lattice parameters a = 0.6623 nm and c = 0.7928 nm and has the composition 49.1 at.% Al-27.7 at.% Si-17.6 at.% Mg-5.6 at.% Fe. Differential thermal analysis of the above alloy shows that the π-AlMgSiFe is formed during cooling at 641 °C with a heat of formation of about 940 kJ/kg. Then α-Si starts forming at 612 °C and Mg2Si at 576 °C. Finally, the metal is solidified as eutectics in two reactions at 558 °C and 549.5 °C. The combined heat of fusion of the two eutectics is ca. 525 kJ/kg, and the phases formed are α-Al, α-Si, Mg2Si and π-AlMg-SiFe.
Abstract
Mit Hilfe von thermodynamischen Berechnungen, DTA-Analysen und Untersuchungen des Gefüges konnten aus einer Al-17.6 Gew.-% Si-7.6 Gew.-% Mg-1.0 Gew.-% Fe Aluminiumschmelze große π-AlMgSiFe-Kristalle gezogen werden. Die π-AlMgSiFe-Kristalle haben ein hexagonales Gitter mit den Parametern a = 0.6623 nm und c = 0.7928 nm. Die chemische Zusammensetzung, 49.1 At.-% Al-27.7 At.-% Si-17.5 At.-% Mg-5.6 At.-% Fe, wurde mit Mikrosondenanalysen ermittelt. Eine DTA-Analyse der Legierung zeigt, daß die Keimbildung der π-AlMgSiFe bei 641 °C beginnt und eine Bildungsenthalpie von ca. 940 kJ/kg hat. Die Ausscheidung von α-Si erfolgt bei 612 °C und die von Mg2Si bei 576 °C. Die Legierung erstarrt zwischen 558 °C und 549.5 °C. Das Eutektikum besteht aus α-Al, α-Si, Mg2Si und π-AlMgSiFe. Die Erstärrungswärme liegt bei ca. 525 kJ/kg.
Literature
1 Mondolfo, L. F.: Aluminium Alloys: Structure and Properties, Butterworths, London (1976) 601–615.Search in Google Scholar
2 Simensen, C. J.; Knudsen, D. A.: Prakt. Metallographie 21 (1984) 55–67.10.1515/pm-1984-210202Search in Google Scholar
3 Perlitz, H.; Westgren, A.: Arkiv för Kemi, Mineralogi og Geologi 16B (1942) 1–16.Search in Google Scholar
4 Kolby, P.; Seiersten, M.; Simensen, C. J.; Tibballs, J. E.: Proceedings of 3rd Int. Conf. on Aluminium Alloys 2 (1992) 26–31.Search in Google Scholar
5 Barlock, J. G.; Mondolfo, L. F.: Z. Metallkd. 66 (1975) 605–611.Search in Google Scholar
6 Cunningham, A. D.; Wilburn, F. W.: in: R. C. Mackenzie (ed.), Differential Thermal Analysis, Academic Press, London (1970) 32–62.Search in Google Scholar
7 Simensen, C. J.; Fartum P.; Andersen, A.: Fresenius Z. Anal. Chemie 319 (1984) 286–292.10.1007/BF00487273Search in Google Scholar
8 Joint Committee on Powder Diffraction Standards 1975 – 1085 (JCPDF-1085) (1975).Search in Google Scholar
9 Phragmén, G.: J. Inst. Metals 77 (1950) 489.Search in Google Scholar
10 Tibballs, J. E.; Davis, R. L.; Parker, B. A.: J. Mater. Sc. 24 (1989) 2177 –2182.10.1007/BF02385438Search in Google Scholar
11 Smithells, C. J.: Metals Reference book 1 Butterworths, London, (1967) 224–226.Search in Google Scholar
12 Tamminen J.: Thermal Analysis for Investigation of Solidification Mechanisms in Metals and Alloys, Chemical Communications No. 2 University of Stockholm (1988).Search in Google Scholar
© 1997 Carl Hanser Verlag, München
Articles in the same Issue
- Frontmatter
- Aufsätze
- Application of the Tomographic Atom Probe to Selected Problems in Materials Science
- Precipitation During Tempering of Chromium-rich Iron-based Martensite Alloyed with Carbon and Nitrogen
- Preparation, Structure and Physical Properties of Fe-, Co- and Ni-rich Melt-quenched Ribbons Containing Zr or Hf
- Phase Formation Kinetics of Titanium Aluminides Produced from Elemental Powder Mixtures
- Hydroxyapatite Coatings on TiNi Shape Memory Alloys
- Thermomechanical Tube Spinning of AA 2014 Aluminum Alloy
- Production of π-AlMgSiFe Crystals
- Gefügeausbildung bei der Umformung im Zweiphasengebiet
- Thermodynamic Evaluation of the Ti–Al–O Ternary System
- Thermodynamic Assessment of the Ag–Mg Binary System
- A Study of Thermal Properties for Fe–Ni –P–B Amorphous Nanosize Powders Prepared by Chemical Reduction
- Determination of Phase Equilibria in the Sm–Fe –Ti System at 600 °C
- Mitteilungen der Deutschen Gesellschaft für Materialkunde e.V.
- Personen
- Tagung
- Fortbildungspraktikum
- Buchbesprechung
- Terminkalender
Articles in the same Issue
- Frontmatter
- Aufsätze
- Application of the Tomographic Atom Probe to Selected Problems in Materials Science
- Precipitation During Tempering of Chromium-rich Iron-based Martensite Alloyed with Carbon and Nitrogen
- Preparation, Structure and Physical Properties of Fe-, Co- and Ni-rich Melt-quenched Ribbons Containing Zr or Hf
- Phase Formation Kinetics of Titanium Aluminides Produced from Elemental Powder Mixtures
- Hydroxyapatite Coatings on TiNi Shape Memory Alloys
- Thermomechanical Tube Spinning of AA 2014 Aluminum Alloy
- Production of π-AlMgSiFe Crystals
- Gefügeausbildung bei der Umformung im Zweiphasengebiet
- Thermodynamic Evaluation of the Ti–Al–O Ternary System
- Thermodynamic Assessment of the Ag–Mg Binary System
- A Study of Thermal Properties for Fe–Ni –P–B Amorphous Nanosize Powders Prepared by Chemical Reduction
- Determination of Phase Equilibria in the Sm–Fe –Ti System at 600 °C
- Mitteilungen der Deutschen Gesellschaft für Materialkunde e.V.
- Personen
- Tagung
- Fortbildungspraktikum
- Buchbesprechung
- Terminkalender
