Effect of Al3Ni and Mg2Si Eutectic Phases on Casting Properties and Hardening of an Al-7% Zn-3% Mg Alloy

Belov, Nikolay A.; Cheverikin, V.V.; Eskin, Dmitry G.; Turchin, A.N.

doi:10.4028/www.scientific.net/MSF.519-521.413

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Thermal Stability of Rapidly Solidified Alloys of Aluminium with Transition Metals
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Microstructure and Phase Composition of Al-Ce-Cu Alloys in the Al-Rich Corner
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The Effect of Heat Treatment and Mn, Cu and Cr Additions on the Structure of Ingots of Al-Mg-Si-Fe Alloys
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Through Thickness Microstructural Gradients in 7475 and 2022 Creep - Ageformed Bend Coupons
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Effect of Al₃Ni and Mg₂Si Eutectic Phases on Casting Properties and Hardening of an Al-7% Zn-3% Mg Alloy
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Mechanical Properties of Dispersion-Hardened P/M Al-Mn-Cu-Mg-Zn Alloys at Elevated Temperature
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Effects of a Small Addition of Cu or Ge on the Microstructure and Mechanical Property of an Al-Si Alloy
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Quantitative Correlation between Strength, Ductility and Precipitate Microstructures with PFZ in Al-Zn-Mg(-Ag, Cu) Alloys
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Home Materials Science Forum Aluminium Alloys 2006 - ICAA10Effect of Al3Ni and Mg2Si Eutectic Phases on...

Effect of Al₃Ni and Mg₂Si Eutectic Phases on Casting Properties and Hardening of an Al-7% Zn-3% Mg Alloy

Abstract:

The formation of eutectics in Al–Zn–Mg–Ni and Al–Zn–Mg–Si systems is studied by means of metallography, DSC, EPMA, X-ray spectroscopy and thermodynamical calculations. Polythermal sections of the corresponding phase diagrams are constructed. The concentrations and temperatures of binary eutectic reactions L → (Al) + Al3Ni and L → (Al) + Mg2Si in quaternary alloys are determined. Nonequilibrium solidification in Al–7% Zn–3% Mg-based alloys ceases at approximately 480 °C. The alloys close by composition to binary eutectics have considerably improved casting properties as compared to the base Al–7% Zn–3% Mg composition. In particular, hot tearing susceptibility is much less in alloys with Al3Ni or Mg2Si. These results are corroborated by measurements of thermal contraction during solidification. The alloys containing binary eutectics exhibit much lower temperatures of contraction onset and less thermal strain is accumulated in the solidification range. Fine eutectic morphology enables fragmentation and spheroidization of intermetallic particles during annealing. The presence of Al3Ni and Mg2Si particles does not decrease the precipitation hardening effect associated with precipitation of the T′ (AlMgZn) phase. Improved casting properties and good mechanical properties of castings allow the application of Al–Zn–Mg alloys with binary eutectics formed by Al3Ni or Mg2Si as foundry alloys.

Info:

Periodical:

Materials Science Forum (Volumes 519-521)

Main Theme:

Aluminium Alloys 2006 - ICAA10

Edited by:

W.J. Poole, M.A. Wells and D.J. Lloyd

Pages:

413-418

DOI:

https://doi.org/10.4028/www.scientific.net/MSF.519-521.413

Citation:

N. A. Belov et al., "Effect of Al₃Ni and Mg₂Si Eutectic Phases on Casting Properties and Hardening of an Al-7% Zn-3% Mg Alloy", Materials Science Forum, Vols. 519-521, pp. 413-418, 2006

Online since:

July 2006

Authors:

Nikolay A. Belov, V.V. Cheverikin, Dmitry G. Eskin, A.N. Turchin

Keywords:

Eutectic Phases, Hot Tearing, Phase Diagram, Thermal Contraction

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References

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[7] N.A. Belov, D.G. Eskin, A.A. Aksenov: Multicomponent Phase Diagrams: Applications for Commercial Aluminum Alloys (Elsevier, Amsterdam/Boston, 2005).

[8] I.I. Novikov: Hot Shortness of Non-Ferrous Metals and Alloys (Nauka, Moscow, 1966) (in Russian).

[9] D.G. Eskin, Suyitno, L. Katgerman: Progr. Mater. Sci. Vol. 49 (2004), p.629.

[10] D.G. Eskin, Suyitno, J.F. Mooney, L. Katgerman: Metall. Mater. Trans. A Vol. 35A (2004), p.1325.

[11] V.S. Zolotorevskii, N.A. Belov: Physical Metallurgy of Foundry Aluminium Alloys (MISiS, Moscow, 2005) (in Russian).

Paper TitlePages

An Analysis of the Development and Applications of Current and New Mg-Al Based Elevated Temperature Magnesium Alloys

Authors: Ming Bo Yang, Fu Sheng Pan, Jing Zhang, Jin Zhang

Abstract: The current status of research and application in the AZ(Mg-Al-Zn), AS(Mg-Al-Si), AE(Mg-Al-RE), AX(Mg-Al-Ca), ACM or MRI（Mg-Al-Ca-RE）and AJ（Mg-Al-Sr）series elevated temperature magnesium alloys are reviewed, will special attention paid to the effects of alloying elements and the control of second phases. The existing problems on the development of elevated temperature magnesium alloys are discussed.

923

Effect of Magnesium and Artificial Aging on the Microstructure and Mechanical Properties of Al-Si-Mn-Mg Alloys

Authors: S.G. Shabestari, M.M. Hejazi, M. Bahramifar

Abstract: The effect of magnesium addition up to 0.9 wt.% on the microstructure and mechanical properties of Al-9Si-0.35Mn alloy has been investigated in both as-cast and heat treated conditions. Generally, Mg addition increases the heat treatability and strength of the alloys at the expense of the lower ductility. High levels of magnesium addition, causes the formation of large and brittle intermetallics, a slight increase in porosity and hence, a decrease in ultimate tensile strength and ductility of the cast alloys. T6 heat treatment increases the strength of the alloys up to 80 percent compared to as-cast samples. Among the studied compositions, heat treated Al-9Si-0.35Mn-0.25Mg alloy, has the maximum value of quality index and can be regarded as a promising material with the optimum mechanical properties for industrial applications.

415

The Microstructure of Rapidly Solidified Al-Zn-Mg-Cu Alloys with Zr Addition

Authors: Lidia Lityńska-Dobrzyńska, Patrick Ochin, Anna Góral, Marek Faryna, Jan Dutkiewicz

Abstract: The effect of rapid solidification on the microstructure of Al-Zn-Mg-Cu alloys with 8 wt.% Zn-2 wt.% Mg-2.3 wt.% Cu and 0.2 or 0.5 wt.% of Zr additions were investigated using X-ray diffraction measurements (XRD), scanning (SEM) and transmission electron microscopy (TEM) combined with energy dispersive X-ray (EDX) microanalysis. Rapidly solidified ribbons with thickness of 70-100 m were performed by melt spinning technique. The mould cast alloys as well as the melt spun ribbons revealed dendritic microstructure of (Al) solid solution and η Mg(Zn,Cu)2 phase in interdendritic areas. The refinement of the microstructure and reduction of the volume fraction of the η phase up to 1.7%, as compared to 4% in the mould cast alloys was observed in the ribbons. Copper dissolution up to about 20 wt % in the η phase causes a decrease of the lattice parameters. The Al3Zr primary precipitates were observed in the mould cast alloy containing 0.5 wt % of Zr while in the ribbons all zirconium dissolved in the aluminium solid solution.

Comparison of Different Content of Cd and Sb Element on the Microstructure, Mechanical Properties of As-Cast AZ31 Magnesium Alloy

Authors: Xiao Ping Luo, Lan Ting Xia, Ming Gang Zhang

Abstract: The effect of Cd and Sb addition on the microstructural and mechanical properties of as-cast AZ31 alloys was investigated and compared. The results indicate that the difference of Sb and Cd in the microstructure and mechanical properties of as-cast AZ31 magnesium alloy is significant. Addition of 0.15%Sb (mass fraction) to AZ31 alloy can refine the matrix and β-Mg₁₇Al₁₂ phase but not form a new phase Mg₃Sb₂. Oppositely, by addition of 0.3-0.7% Cd to AZ31 alloy, Cd was dissolved into the AZ31 alloy, the phase composition did not change but was refined also. Accordingly, the Cd-refined AZ31 alloy exhibits higher tensile and impact toughness and Brinell hardness properties than the Sb- refined one. The difference of Sb and Cd in the mechanical properties is possibly related to the solid solution of Cd into the matrix and formation of Mg₃Sb₂ which has the same close-packed hexagonal structure as α-Mg.

197

Investigation on the Microstructure and Mechanical Properties of New Al-Si Piston Alloys

Authors: S.G. Shabestari, R. Gholizadeh

Abstract: Dense precipitation of various intermetallic compounds is a common feature in the microstructure of Al-Si piston alloys. In this investigation, microstructure of LM13 alloy and three high Cu-containing Al-Si piston alloys with different amounts of Ni, Fe, and Mn were studied by means of optical microscopy (OM) and scanning electron microscopy (SEM). Chemical composition of the phases was determined by using energy dispersive X-ray analysis (EDX). The precipitation of the phases was studied through thermal analysis of the solidifying samples. Also, tensile properties and hardness of the samples were measured. The results showed that the various intermetallics such as Al₁₂(FeMn)₃Si₂, Al₃Ni, Al₉FeNi, and Al₃CuNi precipitated during the solidification. The high Cu-containing alloy with optimum levels of Ni (1.8 wt.%), Fe (0.75 wt.%), and Mn (0.3 wt.%) has the highest tensile strength (250 MPa) and hardness (110 BHN) among the other alloys.

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