Cooling curve and microchemical phase analysis of rapidly quenched magnesium AM60B and AE44 alloys

• Autorzy: Gesing A.J. , Sokołowski J. H. , Marchwica P.C. , Blawert C. , Jekl J. , Kozdras M. , Kasprzak M. , Wood J.
• Języki publikacji: EN

Abstrakty

EN

Purpose: Development of the understanding of the effect of the solidification rate with the alloy microstructures for the structural AM60B and the creep resistant AE44 Mg casting alloys. Design/methodology/approach: Tubular macro test samples of magnesium alloys AM60B and AE44 were melted and quenched at maximum instantaneous cooling rates ranging from -5°C/s to -500°C/s in the Universal Metallurgical Simulator and Analyzer (UMSA) Technology Platform while recording the temperature-time traces. Such rapid cooling rates are typical in water-cooled dies used in high pressure die casting (HPDC). Characteristic reactions on these curves corresponding to the formation of individual phases during solidification were quantified based on cooling curve analysis combined with metallographic and micro-chemical analysis, with the aid of literature data. Findings: The results indicate that these phases, their size and location in the microstructure, their chemistry and their relative proportions all change in response to the increase in the cooling rate. The results are drastically different for the two alloy systems studied. Solidification of AM60B alloy yields small, equiaxed α-Mg rosettes whose size is mostly independent of the cooling rate. These rosettes nucleate heterogeneously on Al8Mn5 phases that are first to form, and are surrounded by the eutectic structure of Mg and Mg17Al12. In contrast, the AE44 has very large α-Mg grains at all cooling rates. These grains are filled with Al11RE3 platelets or dendrites. Results suggest that the Al11Re3 phase is completely ineffective in heterogeneous nucleation of α-Mg grains. Originality/value: In this research the authors significantly extended the thermal analysis methodology. The specific results obtained on the structural and creep-resistant Mg casting alloys are of significant value to the development of automotive light metal structures and power train components as well as further development of solidification codes for the commercial HPDC process.

Słowa kluczowe

EN

AM60; AE44; magnesium; thermal analysis; micro-chemical analysis

PL

magnez; analiza termiczna; analiza mikrochemiczna

• Wydawca: International OCSCO World Press
• Czasopismo: Journal of Achievements in Materials and Manufacturing Engineering
• Rocznik: 2013
• Tom: Vol. 58, nr 2
• Strony: 59--73
• Opis fizyczny: Bibliogr. 11 poz., rys., tab.

Twórcy

autor

Gesing A.J.

• Gesing Consultants Inc., Tecumseh, ON, Canada

autor

Sokołowski J. H.

• University of Windsor, Windsor, ON, Canada

autor

Marchwica P.C.

• University of Windsor, Windsor, ON, Canada

autor

Blawert C.

• Helmholtz-Zentrum Geesthacht Zentrum für Material und Küstenforschung GmbH, Geesthacht, Germany

autor

Jekl J.

• Meridian Lightweight Technologies Inc., Strathroy, ON. Canada

autor

Kozdras M.

• Canmet MATERIALS-Materials Technology Lab, Natural Resources Canada, Hamilton, ON, Canada

autor

Kasprzak M.

• Silesian University of Technology, Gliwice, Poland

autor

Wood J.

• University of Western Ontario, London, ON, Canada

Bibliografia

• [1] A. Kiełbus, Microstructure of AE44 magnesium alloy before and after hot-chamber die casting, Journal of Achievements in Materials and Manufacturing Engineering 20/1-2 (2007) 459-462.
• [2] T. Rzychoń, A. Kiełbus, J. Cwajna, J. Mizera, Microstructural stability and creep properties of die casting Mg–4Al-4RE magnesium alloy, Materials Characterization 60 (2009) 1107-1113.
• [3] J.P. Weiler, J.T. Wood, R.J. Klassen, R. Berkmortel, G. Wang, Variability of skin thickness in an AM60B magnesium alloy die-casting, Materials Science and Engineering 419 (2006) 297-305.
• [4] T. Rzychoń, A. Kiełbus, The influence of wall thickness on the microstructure of HPDC AE44 alloy, Archives of Materials Science and Engineering 28/8 (2007) 471-474.
• [5] W. Huanga, B. Hou, Y. Pang, Z. Zhou, Fretting wear behaviour of AZ91D and AM60B magnesium alloys, Wear 260 (2006) 1173-1178.
• [6] E.W. Jarfors, K.-U. Kainer, M.-J. Tan, J. Yong, Recent developments in the manufacturing of components from aluminium-, magnesium- and titanium-based alloys, COSMOS 5/1 (2009) 23-58.
• [7] J. Gesing, N.D. Reade, J.H. Sokolowski, C. Blawert, Solidification behaviour of recyclable Mg alloys-AZ91 and AZC1231, magnesium technology, The Minerals, Metals & Materials Society (2009) 117-128.
• [8] D. Mirković, R. Schmid-Fetzer, Solidication curves for commercial Mg alloys determined from differential scanning calorimetry with improved heat-transfer modeling, Metallurgical and Materials Transactions A 38A (2007) 2575-2592.
• [9] J. Zhang, K. Liu, D. Fang, X. Qiu, D. Tang, J. Meng, Microstructure, tensile properties, and creep behaviour of high-pressure die-cast Mg-4Al-4RE-0.4Mn (RE = La, Ce) alloys, Journal of Materials Science 44/8 (2009) 2046-2054.
• [10] NIST Chemistry WebBook, http://webbook.nist.gov/chemistry//.
• [11] A.J. Gesing, P. Marchwica, S. Lackie, J. Sokolowski, Quantitative X-ray fluorescence determination of elemental composition of micro-constituents smaller than the electron probe volume, Proceedings of the Characterization of Minerals, Metals and Materials Symposium TMS’2013, San Antonio, 2013, 79-90.