Atomic Scale Investigation on Precipitates and Defects of Mg–RE Alloys: A Review

Zhu, Chenyang; Chen, Bin

doi:10.1002/adem.201800734

Cited by 16 publications

(6 citation statements)

References 82 publications

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“…There are many precipitated phases existing in magnesium alloys, including Mg 17 Al 12 , MgZn 2 , Mg 2 Ca, Mg 5 Gd, Mg 12 Nd and Mg 24 Y 5 , etc., (Nie 2012;Zhu and Chen, 2019;Kaya, 2020;Shi et al, 2020). The crystallography of the precipitated phases determines the microstructure and property of magnesium alloys.…”

Section: Introductionmentioning

confidence: 99%

The Pilling-Bedworth Ratio of Oxides Formed From the Precipitated Phases in Magnesium Alloys

Liu

2021

Front. Mater.

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The Pilling-Bedworth ratio of oxides preferentially formed from the precipitated phases in magnesium alloys were calculated. The results showed that the PBR value of Nd2O3 preferentially formed from Mg12Nd was 1.0584, and the PBR value of Y2O3 preferentially formed from Mg24Y5 was 1.1923. Both the Nd2O3 and Y2O3 would provide a good protection to the Mg matrix. The Gd2O3 preferentially formed from Mg3Gd, whereas the MgO preferentially formed from MgNi2. The PBR value of these two oxides were both larger than 2. The corresponding oxides formed from the common precipitated phases Mg17Al12, MgZn2, MgCu2, Mg2Ca, Mg12Ce, and MgAg were all less than 1. The oxide films formed on surfaces of pure Mg and Mg-xY (x = 3, 5, 7 wt.%) alloys at high temperatures were analyzed. The results showed that the oxide films were composed of a Y2O3/MgO outer layer and an inner layer rich with Y2O3. The formation of Y2O3 was mainly caused by the oxidation of Mg24Y5. The more Y2O3 existed in the composite oxidation film, the better corrosion resistance of the Mg-Y samples.

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Section: Introductionmentioning

confidence: 99%

The Pilling-Bedworth Ratio of Oxides Formed From the Precipitated Phases in Magnesium Alloys

Liu

2021

Front. Mater.

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“…Magnesium alloys have received remarkable attention in applications where weight saving is of great importance due to their low density and high specific strength. [1][2][3] So far, adding rare earth (RE) elements into Mg matrix is one of the effective methods to improve the mechanical properties, [4][5][6][7][8][9] and thus many Mg-RE systems have been developed, such as the Mg-Y system, [10,11] Mg-Gd system, [12][13][14] Mg-Nd system, [15,16] Mg-Ce system, [17,18] etc. Among them, Mg-Gd-based alloys showed promising potential because the maximum solubility of Gd in Mg is really high (23.49 wt% at 548 C), [19] and it decreases rapidly with decreasing temperature.…”

Section: Introductionmentioning

confidence: 99%

“…Magnesium alloys have received remarkable attention in applications where weight saving is of great importance due to their low density and high specific strength . So far, adding rare earth (RE) elements into Mg matrix is one of the effective methods to improve the mechanical properties, and thus many Mg–RE systems have been developed, such as the Mg–Y system, Mg–Gd system, Mg–Nd system, Mg–Ce system, etc.…”

Section: Introductionmentioning

confidence: 99%

Substitution Effects of Gd with Nd on Microstructures and Mechanical Properties of Mg–10Gd–0.4Zr Alloys

et al. 2020

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The microstructures and mechanical properties, especially the contribution of individual strengthening mechanisms, of Mg–10Gd–0.4Zr alloy with the partial substitution of Gd with Nd are studied. The results show that Mg12Nd phases appear in the as‐cast alloys when substituting Gd with Nd, and the volume fraction of the secondary phase increases with increasing Nd content. After solution heat treatment, secondary phases fully dissolve into α(Mg) matrix except for Mg–5Gd–5Nd–0.4Zr alloy, which is attributed to a high Nd content in that alloy, beyond the maximum solubility of Nd in Mg. Age‐hardening curves indicate that substituting Gd with Nd shortens the incubation time and improves the peak hardness. The peak‐aged Mg–7Gd–3Nd–0.4Zr alloy shows improved mechanical properties with the yield strength, ultimate tensile strength, and elongation of 195 MPa, 294 MPa, and 3.9%, respectively, which is attributed to the dense β″ and β′ precipitates formed during aging. Furthermore, the contributions of individual strengthening mechanisms in Mg–Gd–Nd–Zr alloys after different heat treatments are calculated, and the results show that the substitution of Gd with Nd significantly enhances the contribution of precipitation strengthening, especially in peak‐aged Mg–7Gd–3Nd–0.4Zr alloy.

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“…Among Mg alloys, the Mg–Gd–Y system has been extensively studied recently because it offers high tensile strength and excellent creep resistance at temperatures reaching up to 250 °C, indicating potential applicability in the aerospace and aircraft industries. Relatively low shrinkage microporosity susceptibility of Mg–Gd–Y Mg alloys may benefit to the mechanical properties.…”

Section: Introductionmentioning

confidence: 99%

Prediction of Shrinkage Microporosity in Gravity‐Cast and Low‐Pressure Sand‐Cast Mg–6Gd–3Y–0.5Zr Magnesium Alloys

Zhou

Chen

et al. 2019

Adv Eng Mater

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The Niyama criterion and the dimensionless Niyama criterion are used to predict shrinkage microporosity in Mg–6Gd–3Y–0.5Zr magnesium plates processed by gravity casting and low‐pressure sand casting. Instead of the Niyama evaluation condition recommended by commercial ProCAST software and precious studies, the most appropriate Niyama evaluation condition is suggested as fraction solid of 0.7 for the investigated alloys. With consideration of the actual distribution of shrinkage microporosity and the definition of unsound samples (shrinkage microporosity volume fraction is higher than 1% based on the tensile test), the corresponding threshold Niyama values are qualitatively determined as 0.44 and 0.3 °C0.5 s0.5 mm−1 for gravity‐cast and low‐pressure sand‐cast plates, respectively. It indicates that exerting pressure contributes to the decrease in the threshold Niyama value. In addition, exerting pressure can reduce the amount of shrinkage microporosity. For the dimensionless Niyama criterion, it is capable to quantitatively predict the shrinkage microporosity volume fraction in low microporosity‐containing regions, but not in high microporosity‐containing regions.

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Atomic Scale Investigation on Precipitates and Defects of Mg–RE Alloys: A Review

Cited by 16 publications

References 82 publications

The Pilling-Bedworth Ratio of Oxides Formed From the Precipitated Phases in Magnesium Alloys

The Pilling-Bedworth Ratio of Oxides Formed From the Precipitated Phases in Magnesium Alloys

Substitution Effects of Gd with Nd on Microstructures and Mechanical Properties of Mg–10Gd–0.4Zr Alloys

Prediction of Shrinkage Microporosity in Gravity‐Cast and Low‐Pressure Sand‐Cast Mg–6Gd–3Y–0.5Zr Magnesium Alloys

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