Development of the as-cast microstructure in magnesium–aluminium alloys

Dahle, A. K.; Lee, Young C.; Nave, Mark; Schaffer, P. L.; StJohn, David H.

doi:10.1016/s1471-5317(00)00007-9

Cited by 408 publications

(178 citation statements)

References 14 publications

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“…12) A similar phenomenon was observed in a MgAl system, in which the maximum solid solubility of Al decreased from 12.6 to 2 mass% with cooling rate of 0.017 K/s. 13) From the non-equilibrium phase diagram shown in Fig. 3, eq.…”

Section: Resultsmentioning

confidence: 99%

Estimation of Maximum Solid Solubility in Mg–Hg Alloys by the Lever Rule

Wang

2013

Mater. Trans.

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The microstructures of MgHg alloys with 1.12.9 mass% Hg were investigated in this paper. Under the non-equilibrium solidification condition, the examined MgHg alloys had a two-phase structure consisting of a solid solution phase and a spheroidal-graphite iron-like divorced eutectic. Eutectic ¡-Mg and eutectic Mg 3 Hg formed separately, so the proportion of eutectic Mg 3 Hg could be accurately measured. A method was proposed to estimate the maximum solid solubility of Hg in Mg under the non-equilibrium solidification condition by measuring the area fraction of Mg 3 Hg in metallographes. The maximum solid solubility of Mg2.4 mass% Hg was 0.81 and 0.69 mass%, with cooling rates of 0.67 and 2.0 K/s, respectively. The maximum solid solubility decreased as the cooling rate increased and increased as the Hg content increased.

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Section: Resultsmentioning

confidence: 99%

Estimation of Maximum Solid Solubility in Mg–Hg Alloys by the Lever Rule

Wang

2013

Mater. Trans.

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“…1 5 N o . 1 J a n u a r y 2 0 1 8 Overseas Foundry morphology and distribution of the divorced Mg-Al eutectic remarkably affect the performance of die castings, particularly the ductility, corrosion resistance, high temperature strength and creep resistance [17,18] . In view of the above situation, indepth experimental studies have been conducted on the microstructure characteristics of the divorced eutectic of die cast magnesium alloy [19][20][21] .…”

Section: *Lin Huamentioning

confidence: 99%

Modeling studies on divorced eutectic formation of high pressure die cast magnesium alloy

Hua

Xiong

2018

China Foundry

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A s the lightest known structural metals, magnesium alloys have attracted much attention due to their superior properties such as low density, high specific strength, excellent castability, good machinability and recyclability [1,2] . Magnesium alloys have been widely used in automotive, aerospace and 3C (computer, communication and consumer electronics) industries to replace steel, cast iron and even aluminum alloy [3] . The high pressure die casting (HPDC) process is a netshape or near net-shape process with the advantages of high efficiency, considerable economic benefit and high precision of the product size. These remarkable advantages make the HPDC process particularly suitable for various complex productions with magnesium alloys, and generally, magnesium alloy parts are mainly formed by the HPDC process [4] .The performance of magnesium alloy die castings Abstract:The morphology and content of the divorced eutectic in the microstructure of high pressure die casting (HPDC) magnesium alloy have a great influence on the final performance of castings. Based on the previous work concerning simulation of the nucleation and dendritic growth of primary α-Mg during the solidification of magnesium alloy under HPDC process, an extension was made to the formerly established CA (Cellular Automaton) model with the purpose of modeling the nucleation and growth of Mg-Al eutectic. With a temperature field and solute field obtained during simulation of the primary α-Mg dendrites as the initial condition of the modified CA model, modeling of the Mg-Al eutectic with a divorced morphology was achieved. Moreover, the simulated results were in accordance with the experimental ones regarding the distribution and content of the divorced eutectic. Taking a "cover-plate" die casting with AM60 magnesium alloy as an example, the rapid solidification with a high cooling rate at the surface layer of the casting led to a fine and uniform grain size of primary α-Mg, while the divorced eutectic at the grain boundary revealed a more dispersed and granular morphology. Islands of divorced eutectic were observed at the central region of the casting, due to the existence of ESCs (Externally Solidified Crystals) which contributed to a coarse and non-uniform grain size of primary α-Mg. The volume percentage of the eutectic β-Mg 17 Al 12 phase is about 2%-6% in the die casting as a whole. The numerical model established in this study is of great significance to the study of the divorced eutectic in the microstructure of die cast magnesium alloy.

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“…The microstructure refinement due to Ti alloying can be well explained considering the growth restriction factor (GRF) of a solute element, as proposed by Maxwell and Hell [13][14][15] :…”

Section: Microstructure Phase and Composition Of The Alloysmentioning

confidence: 99%

Improved tensile properties of Mg-8Sn-1Zn alloy induced by minor Ti addition

et al. 2016

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Owing to their good mechanical properties at room temperature, conventional Mg-Al and Mg-Zn based alloys have attracted great interest. Unfortunately, they have problems associated with lower creep and corrosion resistance, and cannot meet the requirements of key structural components due to the low thermal stability of the main secondary phase at elevated temperatures (>150 °C) [1][2] . Therefore, it is imperative to develop novel Mg alloys with excellent performance at high temperatures.Mg-Sn based alloys have received considerable attention as potential candidates for high performance casting and wrought magnesium alloys with enhanced thermal stability owing to the presence of high melting temperature (T m ≈ 770 °C) Mg 2 Sn particles in the microstructure [3][4] . However, the coarse Mg 2 Sn phase and the dendritic structure are often present in ascast binary Mg-Sn alloys, hindering their industrial application [5] . Consequently, the modification of the Abstract:In this study, the influence of minor titanium (Ti) addition on the microstructure and tensile properties of Mg-8Sn-1Zn based alloys were investigated by means of optical microscopy, X-ray diffraction, scanning electron microscopy, energy dispersive spectrometry, and tensile tests. The results showed that Ti can decrease the secondary dendrite arm spacing (SDAS). The tensile strength of the Mg-8Sn-1Zn-Ti alloys is initially increased by increasing the Ti content up to 0.09wt.%, but subsequently decreased for further increase of Ti content. The improved tensile properties are attributed to the decreased SDAS and refined Mg 2 Sn phases, as well as the increased fraction of tin (Sn) segregated regions. The tensile fracture surface of the studied alloys shows mixed characteristics of cleavage and quasi-cleavage fracture. Adding Ti does not significantly change the fracture mode of the studied alloys.Key words: Mg-8Sn-1Zn alloy; tensile properties; titanium; tin segregation Micro-alloying can ideally help achieve this goal. The element Ti has been widely used owing to its effectiveness in grain refinement of not only Al-based and Mg-Al alloys, but also of Al-free Mg alloys [6] . Choi et al. [7] reported that a proper control of trace amounts of Ti below the solubility limit has the potential to improve the corrosion resistance of cast Mg-Al alloys by decreasing the grain size and the volume fraction, as well as the size of lamellar (α+β) structures and the divorced eutectic β-phase, with the morphology being transformed from a continuous network structure to a semi-continuous one. Similarly, a study by Candan et al. [8] on AZ91 alloys containing 0.2-0.5wt.% Ti indicated that an improvement in tensile strength can be achieved by introducing Ti to modify the microstructure and refine the grain size. However, until now, only Yang et al. [9] have investigated the effects of minor Ti additions on the ascast microstructure and mechanical properties of Mg-Sn based alloys. The results showed that the addition of 0.1-0.3 wt.% Ti to the Mg-3Sn-2Sr alloy can simulta...

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Development of the as-cast microstructure in magnesium–aluminium alloys

Cited by 408 publications

References 14 publications

Estimation of Maximum Solid Solubility in Mg–Hg Alloys by the Lever Rule

Estimation of Maximum Solid Solubility in Mg–Hg Alloys by the Lever Rule

Modeling studies on divorced eutectic formation of high pressure die cast magnesium alloy

Improved tensile properties of Mg-8Sn-1Zn alloy induced by minor Ti addition

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Development of the as-cast microstructure in magnesium–aluminium alloys

Cited by 408 publications

References 14 publications

Estimation of Maximum Solid Solubility in Mg&ndash;Hg Alloys by the Lever Rule

Estimation of Maximum Solid Solubility in Mg&ndash;Hg Alloys by the Lever Rule

Modeling studies on divorced eutectic formation of high pressure die cast magnesium alloy

Improved tensile properties of Mg-8Sn-1Zn alloy induced by minor Ti addition

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Estimation of Maximum Solid Solubility in Mg–Hg Alloys by the Lever Rule

Estimation of Maximum Solid Solubility in Mg–Hg Alloys by the Lever Rule