Modeling the TDFD dissolution of Al–Fe–Mn–Si particles in an Al–4.5Zn–1Mg alloy

Eivani, A.R.; Ahmed, H.; Zhou, Jie; Duszczyk, J.

doi:10.1080/14786431003662580

Cited by 8 publications

(5 citation statements)

References 38 publications

(86 reference statements)

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“…However, the Mn concentration in the grain interior changes slightly as confirmed by the present EPMA analysis (Fig. 4) and also from modelling results, 27,28 mainly because of the low diffusion rate of Mn in the aluminium matrix. 29 As a result, the Mn concentration is too small in the grain interior to form the Mn containing dispersoids.…”

Section: Resultssupporting

confidence: 83%

“…As mentioned earlier, the Mn containing dispersoids only form at high temperatures (>510°C) and holding times longer than 4 h and only in the grain boundary regions. During homogenisation at high temperatures, these particles may dissolve in the microstructure, thus increasing the Mn concentration in the grain boundary regions 27,28 Figure 4. shows typical results of EPMA measurements of Mn concentration from a linescan across a grain in a sample homogenised at 550°C for 8 h. It is clear that the Mn concentration in the regions close to the Al 17 (Fe 3·2 ,Mn 0·8 )Si 2 particles increases, which is attributed to the dissolution of Al 17 (Fe 3·2 ,Mn 0·8 )Si 2 particles27,28 during homogenisation under this condition.…”

Section: Resultsmentioning

confidence: 99%

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Characterisation of different types of dispersoids present in homogenised Al–4·5Zn–1Mg alloy containing Zr, Cr and Mn

Eivani

Ahmed

Zhou

et al. 2011

Materials Science and Technology

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In the present paper, various types of dispersoids possibly formed during homogenisation of AA7020 alloy containing Cr, Zr and Mn are described. It shows that, in addition to the Zr containing dispersoids, three other types of dispersoids may be present in the homogenised microstructure of AA7020 aluminium alloy. These dispersoids are Cr and Mn containing ones and the one with a mixture of different elements. The Zr and Cr containing dispersoids are formed in the grain interior at all of the homogenisation conditions. However, the Mn containing ones form only in the grain boundary regions in the vicinity of Al17(Fe3·2,Mn0·8)Si2 particles at temperatures ⩾510°C and holding times longer than 4 h.

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Section: Resultssupporting

confidence: 83%

Section: Resultsmentioning

confidence: 99%

Characterisation of different types of dispersoids present in homogenised Al–4·5Zn–1Mg alloy containing Zr, Cr and Mn

Eivani

Ahmed

Zhou

et al. 2011

Materials Science and Technology

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“…Unexpectedly, an unusual phase composed of Al, Fe, Mn, and Si was observed. Al(Fe,Mn)Si phases have been reported in Al–Mg–Si alloys (6 xxx -series) (Lodgaard & Ryum, 2000; Buchanan et al, 2016) and Al–Zn alloys (7 xxx -series) (Eivani et al, 2010, 2011). However, to the best of our knowledge, reports on Al(Fe,Mn)Si phases in 2014Al alloys are scarce.…”

Section: Introductionmentioning

confidence: 99%

Microstructural Characterization and Phase Diagram Calculation of a Less Known Al–Fe–Mn–Si Phase in a SiC_p/2014Al Composite

Ouyang

Zhao

et al. 2019

Microsc Microanal

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A systematic characterization of a less known Al, Fe, Mn, and Si phase in a SiC particulate-reinforced 2014Al composite (SiCp/2014Al) was performed. In addition to the expected CuAl2 phase, the Al, Fe, Mn, and Si phase was formed as either an adhesion (>1 µm) onto SiC in the as-cast composite, or as a precipitate (<100 nm) in the matrix after hot extrusion. The structure of the phase was identified as cubic by both X-ray diffraction and selected area electron diffraction (SAED). The SAED pattern also indicated that the structure belongs to the Pm$\bar{3}$ space group instead of Im$\bar{3}$. The thermodynamic phase diagram was calculated, confirming the presence of an α-AlFeMn or α-AlFeSi phase in the Al–Fe–Mn and Al–Fe–Si ternary systems, respectively, within the Fe, Mn, and Si content range corresponding to 2014Al. Wavelength-dispersive spectroscopy analysis indicated that the composition of the phase is close to Al12(Fe, Mn)3Si2, in which the Mn/Fe ratio is in the range of 0.6–1.4. The determined Mn/Fe ratio corresponds to the nominal composition of Mn and Fe in the alloy.

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“…Although homogenisation of compositional inhomogeneties (usually called 'coring') involve bulk diffusion of the alloying elements, dissolution of secondary phases involves complex interaction between diffusion, surface energy, shape and distribution of secondary phases. Hence, understanding the dissolution mechanism poses more challenging task to the researcher [21][22][23] . understanding the dissolution process of the low melting point secondary phases, such as eutectic and divorced eutectic MgZn 2 -base phases situated mainly at the inter-dendritic channels (IDC) is, therefore, of considerable interest.…”

Section: In-situ Scanning Electron Microscopymentioning

confidence: 99%

“…On the other hand, the dissolution of eutectic phase mixture (α-Al solid solution (dark) and Mg(Zn,Cu,Al) 2 -based η phase (bright)) follows the classical 'spheroidisation' mechanism 29 . Recently, a specific dissolution mechanism called 'Thinning, discontinuation, and full dissolution (TDfD) has been forwarded by Eivani [22][23] , et al to account for the dissolution mechanism of grain boundary phases in AlZn-Mg alloy. The dissolution mechanism of the grain boundary phases with its intermediate stages is schematically illustrated in fig.…”

Section: In-situ Scanning Electron Microscopymentioning

confidence: 99%

Structure-property Characterisation at Nanoscale using In-situ TEM and SEM

Sarkar¹,

Mondal²,

Kumar³

et al. 2016

Def. Sc. Jl.

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In-situ transmission Electron MicroscopyA powerful and unique approach has been developed by integrating the structural information of a material provided by TEM with the properties measured from the same material or with the conditions of structural changes by in-situ TEM 2-3 . This is also an ideal technique for understanding the propertystructure relationship of individual nanostructures. In-situ electron microscopy is an emerging technique for real time visualisation of micro-structural changes of a specimen under some applied constraints inside microscope. In this study, in-situ nanoindentation experimentation on a carbon nanocoil inside transmission electron microscope has been reported. The elastic modulus of the carbon nanocoil is found to be 177 GPa. Similar experiments are also carried out on carbon nanotubes, but force response of carbon nanotubes is beyond the limit of sensors presently available. The in-situ dissolution behaviour of the secondary phases of a 7xxx series aluminum alloy under high vacuum condition in scanning electron microscope (SEM) in the temperature range of 350 °C to 400 °C has been reported. We report for the first time using in-situ SEM technique that dissolution of the MgZn 2 -base phase present as eutectic and divorced eutectic forms could start at a temperature as low as 300 °C, although the usual homogenisation temperature of such alloys is always > 450 °C. Furthermore, the kinetics of dissolution of such phases, particularly when present in fine eutectic phase mixture, is significantly faster than what is observed under atmospheric pressure. It has been found that modification of surface composition under high vacuum condition plays a key role in the low temperature dissolution processes. It has further been found that the dissolution process does not start with the thinning of the inter-dendritic channels phase as proposed for Al-Zn-Mg-Cu alloys, rather it occurs by a combination of 'spheroidisation' and thinning process called 'the thinning, discontinuation, and full dissolution' mechanism. Results of the in-stu experiments under high vacuum are compared with the ex-situ dissolution experiments under normal atmospheric pressure.

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Modeling the TDFD dissolution of Al–Fe–Mn–Si particles in an Al–4.5Zn–1Mg alloy

Cited by 8 publications

References 38 publications

Characterisation of different types of dispersoids present in homogenised Al–4·5Zn–1Mg alloy containing Zr, Cr and Mn

Characterisation of different types of dispersoids present in homogenised Al–4·5Zn–1Mg alloy containing Zr, Cr and Mn

Microstructural Characterization and Phase Diagram Calculation of a Less Known Al–Fe–Mn–Si Phase in a SiC_p/2014Al Composite

Structure-property Characterisation at Nanoscale using In-situ TEM and SEM

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Modeling the TDFD dissolution of Al–Fe–Mn–Si particles in an Al–4.5Zn–1Mg alloy

Cited by 8 publications

References 38 publications

Characterisation of different types of dispersoids present in homogenised Al–4·5Zn–1Mg alloy containing Zr, Cr and Mn

Characterisation of different types of dispersoids present in homogenised Al–4·5Zn–1Mg alloy containing Zr, Cr and Mn

Microstructural Characterization and Phase Diagram Calculation of a Less Known Al–Fe–Mn–Si Phase in a SiCp/2014Al Composite

Structure-property Characterisation at Nanoscale using In-situ TEM and SEM

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Microstructural Characterization and Phase Diagram Calculation of a Less Known Al–Fe–Mn–Si Phase in a SiC_p/2014Al Composite