Influence of a high magnetic field on the precipitation behavior of the primary Al3Fe phase during the solidification of a hypereutectic Al-3.31wt% Fe alloy

et al. 2014

J Appl Cryst

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Hypoeutectic Zn-4.45 wt% Al solidified under a high magnetic field was investigated crystallographically. With the field, the primary zinc-rich phase is distributed homogeneously and orients with the c axis perpendicular to the magnetic field direction. These results are attributed to the magnetic viscosity resistance force and the magnetocrystalline anisotropy of zinc, respectively. The orientation modification also leads to a preferential alignment of the flat-shaped primary dendrites. Furthermore, with the field, the eutectic phase shows an orientation character similar to that of the primary phase. This arises from its continuous growth with the primary phase. In addition, a specific crystallographic orientation relationship ({0001} || {111} , h1210i || h110i ) exists in some of the eutectics (between the eutectic zinc-rich and aluminium-rich phases). However, this orientation relationship is related to the distribution of primary dendrites, which originates from the independent nucleation of the pseudo-primary phase attached to the primary dendrites.

Section: Morphologymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Crystallographic effect of a high magnetic field on a solidified hypoeutectic Zn–Al alloy

et al. 2014

J Appl Cryst

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“…Crystals 2017, 7, 204 2 of 10 (usually negligible in conventional magnetic fields), thereby imposing more abundant effects on the structures of the alloys [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]. It has been found that the HMFs could orient and align the structures [13][14][15][16][17], increase the phase transformation temperature [19], enhance the magnetic coercivities [16], suppress the diffusion of solute elements [21], modify the orientation relationship between the eutectics [22], and change the solid-liquid interface morphologies [23]. Hexagonal close-packed zinc is characterized by large solid-liquid interfacial energy anisotropy [24,25] and magnetocrystalline anisotropy [13,14].…”

Section: Resultsmentioning

confidence: 99%

Morphological and Crystallographic Characterization of Primary Zinc-Rich Crystals in a Ternary Sn-Zn-Bi Alloy under a High Magnetic Field

Ban

et al. 2017

Crystals

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Due to the unique capacity for structural control, high magnetic fields (HMFs) have been widely applied to the solidification process of alloys. In zinc-based alloys, the primary zinc-rich crystals can be dendritic or needle-like in two dimensions. For the dendritic crystals, their growth pattern and orientation behaviors under HMFs have been investigated. However, the three-dimensional crystallographic growth pattern and the orientation behaviors of the needle-like primary zinc-rich crystals under a high magnetic field have not been studied. In this work, a ternary Sn-Zn-Bi alloy was solidified under different HMFs. The above-mentioned two aspects of the needle-like primary zinc-rich crystals were characterized using the Electron Backscattered Diffraction (EBSD) technique. The results show that the primary zinc-rich crystals are characterized by the plate-shaped faceted growth in three dimensions. They grow in the following manner: spreading rapidly in the {0001} basal plane with a gradual decrease in thickness at the edges. The application of HMFs has no effect on the growth form of the primary zinc-rich crystals, but induces their vertical alignment. Crystallographic analysis indicates that the vertically aligned primary zinc-rich crystals orient preferentially with the c-axis perpendicular to the direction of the magnetic field.

“…It has been proved during the solidification of some other alloys (Jin et al, 2008;Li et al, 2012) that the application of a high magnetic field can 'levitate' the primary crystals and homogenize their distribution in the sample as a result of the induced magnetic viscosity resistance force. However, in the present work, the density of crystalline Al 3 Zr is much higher than that of the Al melt, so the magnetic field is not sufficient to suppress their descent.…”

Section: Figurementioning

confidence: 99%

“…The surrounding liquid medium provides a free environment for these crystals to rotate. If a magnetic field is applied, they can be oriented and then generate a special alignment (Liu et al, 2009;Li et al, 2012). Recently, considerable attention has been paid to the study of aluminium alloys (Li et al, 2009a(Li et al, ,b, 2010.…”

Section: Introductionmentioning

confidence: 99%

A microstructural and crystallographic investigation of the precipitation behaviour of a primary Al₃Zr phase under a high magnetic field

Esling

et al. 2013

J Appl Cryst

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The effects of a high magnetic field on the precipitation behaviour of the primary Al3Zr phase are investigated. With and without the field, the primary Al3Zr crystals possess three morphologies – small tabular crystals in the deposit layer, long bars and dendritic crystals. The dendritic crystals are probably those surviving from the initial material. The tabular crystals in the deposit layer are those surviving from the heating stage, whereas the long bars are those formed during cooling. With the field, the tabular crystals in the deposit layer and the long bars tend to orient with the 〈110〉 direction parallel to the field direction, but the orientation of the dendritic crystals is less affected. The orientation of the crystals in the deposit layer arises from their magnetocrystalline anisotropy, but that of the long bars and dendritic crystals is disturbed by gravity and the formation of compound twins, respectively. Increased Zr content raises the precipitation amount of the primary Al3Zr crystals but weakens the alignment tendency of the tabular ones in the deposit layer. The weakness of the alignment arises from interaction between the crystals.