Effect of rare earth elements on the microstructure of Mg-Al alloys

• Autorzy: Rzychoń T. , Kiełbus A.
• Języki publikacji: EN

Abstrakty

EN

Purpose: The automotive use of magnesium is currently restricted to low-temperature structural components. Rare earth additions such as Ce, Nd, La and Pr are known to improve the creep performance. The aim of the research was to determine the effect of rare earths elements on the as-cast microstructure of magnesium alloys containing 4 wt% aluminum. Design/methodology/approach: The study was conducted on Mg-4Al-2RE (AE42) and a new Mg-4Al-4RE (AE44) alloys in the as-cast condition. The microstructure was characterized by optical microscopy (Olympus GX-70) and a scanning electron microscopy (Hitachi S3400) equipped with an X-radiation detector EDS (VOYAGER of NORAN INSTRUMENTS). The phase identification of these alloys was identified by X-ray diffraction (JDX-75). Findings: The microstructure of AE42 alloy consists of α-Mg solid solution with divorced eutectic Mg17Al12 + α-Mg, RE-rich phases and Mn-rich phase. The increase of RE contents from 2 wt% to 4 wt% leads to a change of microstructure of these alloys. In AE44 alloy was observed globular, lamellar and acicular precipitations of Al11RE3 and Al3RE phases. Moreover, there was found globular Mn-rich phase existence, but the Mg17Al12 phase was not observed. Research limitations/implications: The increase of RE content to 4 wt% caused the formation of new phases in the microstructure and prevented the formation Mg17Al12 phase. These factors can improve the creep resistance of the Mg-Al-RE alloys. The future research will contain creep tests and microstructural investigations of cast and die-cast alloys using TEM microscopy. Practical implications: The improvement of creep resistance of Mg-Al alloys can cause their application in automotive industry on the elevated-temperature structural components (above 150°C). Results of investigation may be useful for preparing die casting technology of the Mg-Al-RE alloys. Originality/value: paper includes the results of microstructural investigations of new AE44 magnesium alloy for die casting technology.

Słowa kluczowe

EN

metallic alloys; magnesium-aluminum-rare earth alloys; microstructure

PL

stopy metaliczne; stopy ziem rzadkich; mikrostruktura

• Wydawca: International OCSCO World Press
• Czasopismo: Journal of Achievements in Materials and Manufacturing Engineering
• Rocznik: 2006
• Tom: Vol. 17, nr 1-2
• Strony: 149--152
• Opis fizyczny: Bibliogr. 16 poz., rys., tab., wykr.

Twórcy

autor

Rzychoń T.

• Faculty of Materials Science and Metallurgy, Silesian University of Technology, ul. Krasińskiego 8, 40-019 Katowice. Poland

autor

Kiełbus A.

• Faculty of Materials Science and Metallurgy, Silesian University of Technology, ul. Krasińskiego 8, 40-019 Katowice. Poland

Bibliografia

• [1] B.L. Mordike, Development of highly creep resistant magnesium alloys, Journal of Material Processing Technology, 117, (2001), 391-394.
• [2] Z. Xiaoquin, W. Quodong, L. Yizhen, Z. Yanping, D. Wenjiang, Z. Yunhu, Influence of beryllium and rare earth additions on ignition-proof magnesium alloys, Journal of Material Processing Technology, 112, (2001), 17-23.
• [3] H. Friedrich, S. Schumann, Research for a “new age of magnesium” in the automotive industry, Journal of Material Processing Technology, 117, (2001), 276-281.
• [4] A. Kiełbus, T. Rzychoń, Microstructural characterization of Mg-Al magnesium alloys, Proceedings of the 13th scientific conference “New Technologies and Materials in Metallurgy and Materials Science and Engineering”, Katowice, 2005, 117-122 (in Polish)
• [5] M.O. Pekguleryuz, E. Baril, Creep resistant Magnesium Diecasting Alloys Based on Alkaline Earth Elements, Materials Transactions, Vol. 42, No. 7 (2001) 1258-1267.
• [6] S. Xue, Y.S. Sun, S.S. Ding, Q. Bai, J. Bai, Effects of calcium additions on microstructure and creep behavior of AE42 alloy, Materials Science and Technology, Vol. 21, No. 7, 2005, 847-853.
• [7] B.R. Powell, V. Rezhets, M.P. Balogh, R.A. Waldo, Microstructure and Creep Behavior in AE42 Magnesium Die-Casting Alloy, JOM, August 2002, 34-38.
• [8] AE alloys – the new family of creep resistant die casting alloys, Diecaster Bulletin, No. 11, October 2004.
• [9] P. Bakke, H. Westengen, The role of rare earth elements in structure and property control of magnesium die casting alloys, TMS, Magnesium Technology 2005, 291-296.
• [10] T. Rzychoń, A. Kiełbus: Microstructure of the die cast Mg-4Al with rare earth addition, Proceedings of the 23rdConference “Materials Science and Engineering School”, Krakow-Ustron, 2005, 149-154.
• [11] A.A. Luo, Recent magnesium alloy development for elevated temperature applications, International Materials Reviews, Vol. 49, No. 1, 2004, 13-32.
• [12] N.A. El-Mahallawy, M.A. Taha, E. Pokora, F. Klein, On the influence of process variables on the thermal conditions and properties of high pressure die-cast magnesium alloys, Journal of Material Processing Technology, 73, (1998), 125-138.
• [13] K. Davey, S. Bounds, Modelling the Pressure Die Casting Process using Boundary and Finite Elements Methods, Journal of Material Processing Technology, 63 (1997), 696-700.
• [14] M.M. Avedesian, H. Baker, ASM Spiecalty Handbook, Magnesium and Magnesium Alloys, 1999.
• [15] Y. Lü, Q. Wang, X. Zeng, W. Ding, C. Zhai, Y. Zhu, Effects of rare earths on the microstructure, properties and fracture behavior of Mg-Al alloys, Materials Science and Engineering A278 (2000) 66-76.
• [16] L.Y. Wei, G.L. Dunlop, H. Westengen, Development of microstructure in cast Mg-Al-rare earth alloys, Materials Science and Technology, Vol. 12, 1996, 741-750.