Effect of Temperature on the Lattice Parameters of Magnesium Alloys

Busk, Robert S.

doi:10.1007/bf03397674

Cited by 13 publications

(7 citation statements)

References 4 publications

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“…These calculated values of a and c are matched with recorded values in JCPDS card no. 65-3365 for Mg matrix, and they agreed well with the values reported in the literature[39,41]. The separation of aluminum to form β-Mg 17 Al 12 phase may be held responsible for the alteration in the lattice parameter values.…”

supporting

confidence: 89%

“…Thus, the volume fraction of continuous precipitates grew as the aging time increased from 24 to 96 h, and that of discontinuous precipitation gradually reduced, resulting in lower hardness values. Earlier studies [39,40] declared that discontinuous precipitates were effectively inhibited as the continuous precipitates were formed. Dissimilar to the microstructure of the sample aged for 92 h (Figure 7c), plenty of lath-shaped precipitates occupied the whole sample, and no discontinuous precipitates were detected (Figure 7d).…”

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confidence: 99%

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Simulation and Prediction of the Vickers Hardness of AZ91 Magnesium Alloy Using Artificial Neural Network Model

et al. 2020

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In this study, an artificial neural network (ANN) model was used to simulate and predict the Vickers hardness of AZ91 magnesium alloy. The samples of AZ91 alloy were aged at different temperatures (Ta = 100 to 300 °C) for different durations (ta = 4 to 192 h) followed by water quenching at 25 °C. The age-hardening response of the samples was investigated by hardness measurements. The microstructure investigations showed that only discontinuous precipitates formed at low aging temperatures (100 and 150 °C), while continuous precipitates invaded all the samples at a high aging temperature (300 °C). Both discontinuous and continuous precipitates formed at the intermediate aging temperatures (200 and 250 °C). X-ray diffraction (XRD) analysis revealed that the microstructure comprised two phases: The α-Mg matrix and intermetallic β-Mg17Al12 phase. The alteration of the crystalline lattice parameters a, c, and c/a ratio with the aging time at various aging temperatures was also investigated. Both c and c/a ratio had the same behavior with aging time while a had an inverse trend. The observed variations of the lattice parameters were attributed to the mode of precipitation in AZ91 alloy. The ANN findings for the simulation and prediction perfectly conformed to the experimental data.

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confidence: 89%

Section: = ( − )mentioning

confidence: 99%

Simulation and Prediction of the Vickers Hardness of AZ91 Magnesium Alloy Using Artificial Neural Network Model

et al. 2020

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“…To determine the structural stability of flawless and nanotwinned Mg 2 Si, We calculated the elastic matrix elements (See Table S1 in the SM) and used the Voigt-Reuss-Hill relationship to calculate the B and G (Table. 1) [52]. We found that G = 32.4 GPa in nanotwinned Mg 2 Si is significantly lower (36%) than that (50.6 GPa) in the flawless crystal.…”

Section: Resultsmentioning

confidence: 65%

Dramatically reduced lattice thermal conductivity of Mg2Si thermoelectric material from nanotwinning

et al. 2019

Acta Materialia

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Dramatically reduced lattice thermal conductivity of Mg 2 Si thermoelectric material from nanotwinning, Acta Materialia, https://doi. Abstract:Tuning phonon transport to reduce the lattice thermal conductivity (κ L ) is crucial for advancing thermoelectrics (TEs). Traditional strategies on κ L reduction focus on introducing scattering sources such as point defects, dislocations, and grain boundaries, that may degrade the electrical conductivity and Seebeck coefficient. We suggest here, a novel twin boundary (TB) strategy that can decrease the κ L of Mg 2 Si by ~90%, but which may not degrade the electrical properties significantly. We validate this suggestion using density functional theory (DFT). We attribute the mechanism of TB induced κ L reduction to (i) the lower phonon velocities and larger Grüneisen parameter, (ii) "rattling" of the Mg−Mg pair induced soft acoustic and optical modes, (iii) shorter phonon lifetime and higher phonon scattering rate. We predict that the size of nanotwinned structure should be controlled between 3 nm and 100 nm in the Mg 2 Si matrix for the most effective κ L reduction. These results should be applicable for other TE or non TE energy materials with desired low thermal conductivity, suggesting rational designs of high-performance Mg 2 Si TE materials with low κ L for the energy conversion applications. Functional Theory 0.4 W m −1 K −1 and a zT of 1.5 at 1000 K [21]. In SnSe single crystals, The lattice anharmonicity leads to an exceptionally low κ L of 0.23 ± 0.03 W m −1 K −1 and an unprecedented zT of 2.6 ± 0.03 at 923 K [22,23]. In such TE materials as MgAgSb [24], Ag 5-δ Te 3 [25], and Ag 8 SnSe 6 [26], the complex crystal structure or weak chemical bonds leads to low heat capacity or low speed of sound, well explaining the low intrinsic κ L of < 0.5 W m −1 K [24-26]. Introducing phonon scattering sources such as point defects [27-29], dislocations [30-32], grain boundaries [33-35], can effectively shorten phonon relaxation time, giving rise to reduction in κ L . Multiple fillers inCoSb 3 can achieve broad-frequency phonon scattering, reducing κ L to the glass limit value of 0.2 W m −1 K −1 , and leading to an extremely high zT of 1.7 at 850 K [29]. Full-spectrum phonon scattering, which was achieved through grain boundary, dense dislocation arrays, and point defect,

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“…The lattice spacings of Mg-Cd alloys as a function of composition at 310°C (HUME-ROTHERY and RAYNOR, 1940).in Mg but not in Cd, for this would be expected to show a slight influence on the a spacing BUSK (1952). has examined the effect of temperature on the electron concentration at which the B overlap takes place in these alloys, with the result shown inFig.…”

mentioning

confidence: 99%

Structure Determination and Lattice Spacings in the Theory of Alloy Formation

Pearson¹

1958

A Handbook of Lattice Spacings and Structures of Metals and Alloys

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Effect of Temperature on the Lattice Parameters of Magnesium Alloys

Cited by 13 publications

References 4 publications

Simulation and Prediction of the Vickers Hardness of AZ91 Magnesium Alloy Using Artificial Neural Network Model

Simulation and Prediction of the Vickers Hardness of AZ91 Magnesium Alloy Using Artificial Neural Network Model

Dramatically reduced lattice thermal conductivity of Mg2Si thermoelectric material from nanotwinning

Structure Determination and Lattice Spacings in the Theory of Alloy Formation

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