Thermodynamic modeling and diffusion kinetic experiments of binary Mg–Gd and Mg–Y systems

Das, Sourav; Kang, Youn‐Bae; Ha, Tae Kwon; Jung, In‐Ho

doi:10.1016/j.actamat.2014.02.029

Cited by 148 publications

(49 citation statements)

References 41 publications

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“…Figure 5 shows the calculated values of the grain boundary segregation energy (DG seg ) for Ni and Y from the present results as well as for Gd using the relative compositions reported in the literature for matrix and grain boundary regions. [9] Also shown are the lattice diffusion coefficients at 673 K (400°C) calculated in the case of Gd and Y from the data of Das et al [17] and estimated in the case of Ni, where no accurate measurements of diffusion coefficient in Mg are reported. The diffusion coefficient for Ni in Mg was estimated from the diffusion coefficient (D) of Ni in Al, for which measurements are available.…”

Section: Solute Drag Modelmentioning

confidence: 99%

“…For Y and Gd in Mg, D 0 and Q for bulk diffusion were given by Reference 17. The anisotropy in the diffusion coefficient (which is small at the temperatures of interest here [17] ) was ignored. There are no reported data for the impurity diffusion coefficient of Ni in Mg, and so this was taken from the values reported for Ni in Al; the justification for this is discussed later.…”

Section: Modelmentioning

confidence: 99%

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Grain Boundary Segregation of Rare-Earth Elements in Magnesium Alloys

Robson

Haigh

Davis³

et al. 2015

Metall Mater Trans A

124

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Small additions of rare-earth (RE) elements have been shown to have a powerful effect in modifying the texture of wrought magnesium alloys, giving a highly beneficial effect in improving their formability. Recent work has shown that segregation of RE atoms to grain boundaries is important in producing this texture change. In this work, two Mg-RE systems have been studied Mg-Y and Mg-Nd using high-resolution scanning transmission electron microscopy that permits both imaging and elemental analysis with a spatial resolution of better than 0.1 nm. The Mg-Y alloy, where the solubility and level of addition are relatively high, showed the RE texture change effect. This was accompanied by clustering of Y on the grain boundaries, consistent with previous studies of the Mg-Gd system. The Mg-Nd alloy, where the solubility and level of addition are relatively low, showed no texture change and no segregation. In this case, impurity elements binding the RE into insoluble particles, rendering it ineffective. The results are analyzed by modifying a previous model for the solute drag effect on boundaries expected due to the RE additions. This predicts that both Gd and Y will strongly inhibit boundary motion, with Gd being approximately twice as effective as Y.

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Section: Solute Drag Modelmentioning

confidence: 99%

Section: Modelmentioning

confidence: 99%

Grain Boundary Segregation of Rare-Earth Elements in Magnesium Alloys

Robson

Haigh

Davis³

et al. 2015

Metall Mater Trans A

124

View full text Add to dashboard Cite

show abstract

“…Magnesium alloys may substitute for aluminum and steel in aerospace and automotive industries with their higher specific strengths [9][10][11]. The growing interest in magnesium has driven experimental [12][13][14][15][16][17][18][19] and computational [20][21][22][23] studies of transport coefficients of the common Al and Zn solutes that improve strength and rare earth elements that improve ductility. Transport coefficients are fundamental inputs for models at the length and time scales of microstructure evolution.…”

mentioning

confidence: 99%

Exact Model of Vacancy-Mediated Solute Transport in Magnesium

Agarwal

Trinkle

2017

Phys. Rev. Lett.

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“…Accordingly, due to the low diffusion rates of these elements in magnesium, the RE elements may retard recrystallization so that higher temperatures are required for the onset of recrystallization in RE-containing Mg alloys. In this respect, the diffusion coefficients of Y and Gd in Mg are similar but they are almost one order of magnitude lower than for Al and Zn which are the conventional alloying elements in magnesium [38,39].…”

Section: Microstructural and Textural Evolution After Sptmentioning

confidence: 74%

Microstructural evolution during hot shear deformation of an extruded fine-grained Mg–Gd–Y–Zr alloy

et al. 2017

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Abstract:Mg-Gd-Y-Zr alloys are among recently developed Mg alloys having superior mechanical properties at elevated temperatures. Dynamic recrystallization (DRX) and rare earth (RE)-rich particles play important roles in enhancing the high temperature strength of these alloys. Accordingly, the microstructural evolution of a fine grained extruded Mg-5Gd-4Y-0.4Zr alloy was investigated after hot shear deformation in the temperature range of 350-450 °C using the shear punch testing (SPT) method. The results reveal the occurrence of partial dynamic recrystallization at the grain boundaries at 350 °C while the fraction of DRX grains increases with increasing deformation temperature. A fully-recrystallized microstructure was achieved after SPT at 450 °C. The Gd-rich and Y-rich cuboid particles, having typical sizes in the range of ~50 nm to ~3 m, show excellent stability and compatibility after hot shear deformation and these particles enhance the high temperature strength during hot deformation at elevated temperatures. The textural evolution, examined using electron backscattered diffraction (EBSD), revealed a non-fibrous basal DRX texture after SPT which is different from the conventional deformation texture.

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Thermodynamic modeling and diffusion kinetic experiments of binary Mg–Gd and Mg–Y systems

Cited by 148 publications

References 41 publications

Grain Boundary Segregation of Rare-Earth Elements in Magnesium Alloys

Grain Boundary Segregation of Rare-Earth Elements in Magnesium Alloys

Exact Model of Vacancy-Mediated Solute Transport in Magnesium

Microstructural evolution during hot shear deformation of an extruded fine-grained Mg–Gd–Y–Zr alloy

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