Solidification of Cast Magnesium Alloys

StJohn, David H.; Dahle, A. K.; Abbott, Trevor B.; Nave, Mark; Qian, Ma

doi:10.1002/9781118859803.ch32

Cited by 10 publications

(20 citation statements)

References 16 publications

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“…The theoretical fractions of constituent phases, based on the lever rule and listed in Table 1 were dispersed at the grain boundaries of the eutectic b-Mg 17 Al 12 [27]. However, as clearly seen in the microstructures of the as-cast AZ91ÀxSn alloys, such as that of AZ91À3Sn in Fig.…”

Section: As Suggested By Anmentioning

confidence: 99%

Refined microstructure and improved mechanical properties of high-ratio extruded AZ91−xSn magnesium alloy

Yeh

Chang

2015

Materials Chemistry and Physics

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Section: As Suggested By Anmentioning

confidence: 99%

Refined microstructure and improved mechanical properties of high-ratio extruded AZ91−xSn magnesium alloy

Yeh

Chang

2015

Materials Chemistry and Physics

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“…This is dictated by ecology and reduced energy consumption. It also results in a growing interest in low-density materials, mainly magnesium and its alloys [1][2][3].…”

Section: Introductionmentioning

confidence: 99%

“…A French chemist Antoine Bussy, on the other hand, developed another method of producing metallic magnesium. He published in Mémoire sur le Radical métallique de la Magnésie (1831) the process of obtaining magnesium which involves heating magnesium chloride (MgCl 2 ) and potassium (K) in the retort [1,3,4].…”

Section: Introductionmentioning

confidence: 99%

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Introductory Chapter: Magnesium Alloys

Tański¹,

Król²

2018

Magnesium Alloys - Selected Issue

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“…The basic process summarised above has been verified by several researchers [47][48][49]. Particularly, the presence of the characteristic Zr-rich coring, and a cen- Fig.…”

Section: Mechanism Of Grain Refinement By Zirconiummentioning

confidence: 56%

Melting, Alloying and Refining

Magnesium Technology

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With the automotive, electronic and consumer goods industries embracing magnesium in their applications, magnesium alloys that do not contain zirconium have gained a higher market share than alloys which do. The zirconium-free alloys include important alloy classes such as Mg-Al, Mg-Al-Zn, Mg-Al-Si, Mg-Al-(Rare-Earths), Mg-Al-(Alkaline Earths), Mg-Li and alloys that contain a number of rare alloying elements such as combinations of rare earths, alkaline earths and lanthanides. While Mg-Al, Mg-Al-Zn and Mg-Al-Si are commercial, the other alloy systems are either semi-commercial or being developed. Mg-Al, Mg-Al-Zn, and Mg-Al-Si AlloysThe main alloying elements in these alloys are two or more of the elements from the following list: Al, Zn, Mn, Be, Si.Addition of Al, Zn, and Si are straightforward [1] while Mn and Be require more control. Magnesium can be melted and alloyed to produce Mg-Al based alloys using electric resistance, gas-fired and induction furnaces with mild steel crucibles.As in all magnesium alloys, Mg-Al based alloy melts must be protected against oxidation and burning during melting, alloying and casting. The Mg-Al alloy-melt forms a porous MgO-Al 2 O 3 surface layer, which does not offer resistance to oxidation and burning. Fluxes (employing molten salt mixtures) or fluxless-melting techniques (using protective gas mixtures, such as SO 2 , or SF 6 mixed with CO 2 , dry air or N 2 ) can be used depending on alloy compositions and processing conditions. Flux Melting and RefiningFlux melting, alloying and refining of Mg-Al based alloys has had a long historical development. This can be found in detail in Emley's classic book on magnesium technology [1, pp. 72-73]. Early fluxes consisted of MgCl 2 , which would solidify above the melting point of Mg. This led to chloride inclusions in the melt (Fig. 4.1).In order to solve these problems a number of methods were developed. Flux compositions were usually adjusted to melt below the melting point of the alloys CHAPTER 1 so that they spread-out and protect the solid metal from oxidation prior to melting. Alkaline earth metal chlorides such as BaCl 2 were added to adjust the melting point.Another early method involved the addition of porous substances such as MgO to absorb the chlorides. These techniques did not provide the optimum solution but added to the overall knowledge base on flux melting of Mg.BaCl 2 was also commonly part of the composition of early fluxes due to its high density, which would encourage the flux and the flux-oxide particulates to settle to the bottom. The elimination of BaCl 2 due to environmental regulations prompted wider use of inspissated (thick) flux to promote separation by agglomeration due to the surface tension or tacky character of the salt phase. Between 1922 and 1938, the development of thickened (inspissated fluxes) consisting of MgCl 2 and thickening agents such as MgO and MgF 2 were developed. The flux could provide a thin viscous protective layer on the melt surface and avoided the risk of chloride inclusions arising...

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Solidification of Cast Magnesium Alloys

Cited by 10 publications

References 16 publications

Refined microstructure and improved mechanical properties of high-ratio extruded AZ91−xSn magnesium alloy

Refined microstructure and improved mechanical properties of high-ratio extruded AZ91−xSn magnesium alloy

Introductory Chapter: Magnesium Alloys

Melting, Alloying and Refining

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