Effects of Alloying Elements on Stacking Fault Energies and Electronic Structures of Binary Mg Alloys: A First-Principles Study

Wang, William Yi; Shang, Shun‐Li; Wang, Yi; Mei, Zhi-Gang; Darling, Kristopher A.; Kecskes, Laszlo J.; Mathaudhu, Suveen; Xian, Hui; Liu, Zhe

doi:10.1080/21663831.2013.858085

Cited by 102 publications

(45 citation statements)

References 57 publications

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“…Atomic-scale simulations, including molecular statics/ molecular dynamics (MS/MD) and ab initio DFT, have proved to be a valuable tool in recent decades for studying the character and stability of structural defects, and the energetic and kinetics aspects of defect nucleation, reactions and interactions [45][46][47][48][49][50]. MS/MD simulations use an empirical potential to model the interatomic forces, and have the capability of handling the motion of millions to billions of atoms on nanosecond timescales [51,52].…”

Section: Methodsmentioning

confidence: 99%

First-principles study of energy and atomic solubility of twinning-associated boundaries in hexagonal metals

2015

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Twinning-associated boundaries (TB), f1 0 1 ng coherent twin boundaries (CTB) and the coherent basal-prismatic (CBP) boundary in six hexagonal metals (Cd, Zn, Mg, Zr, Ti and Be) are studied using first-principles density function theory, with the focus on the structural character of TB and the solute's solubility at TB. Regarding the structure and energy of TB, the formation of TB is associated with the creation of an excess volume. All six metals show positive excess volume associated with ð1 0 1 1Þ and ð1 0 1 3Þ CTB, but the excess volume associated with ð1 0 12Þ CTB and CBP can be positive or negative, depending on the metal. The ð1 0 1 2Þ CTB has higher excess energy than ð1 0 1 1Þ and ð1 0 1 3Þ CTB for metals with c=a < ffiffiffiffiffiffiffi ffi 8=3 p , but lower for metals with c=a > ffiffiffiffiffiffiffi ffi 8=3 p . More interestingly, CBP has lower excess energy than ð1 0 1 2Þ CTB for all metals. This is consistent with the recent finding concerning the pure-shuffle nucleation mechanism of ð1 0 1 2Þ twins. To understand solubility at TB, the solubility of solute atoms in Mg, Ti and Zr is calculated for solute positions in bulk, ð1 0 1 2Þ CTB and CBP boundaries. In general, solute atoms have better solubility at CTB and CBP than in bulk. Interestingly, the solubility of solute atoms changes linearly with normal strain at CBP, increasing with normal strain for solute atoms with a greater metallic radius than the matrix, and decreasing with normal strain for solute atoms with a smaller metallic radius than the matrix. This suggests that the distribution of solute atoms in bulk, CTB and CPB boundaries varies with stress state and, in turn, affects the mobility of TB.

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Section: Methodsmentioning

confidence: 99%

First-principles study of energy and atomic solubility of twinning-associated boundaries in hexagonal metals

2015

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“…The prediction of material stability and mechanical properties is critical for rational design of heterointerfaces. Stacking energy [29][30][31] is a critical parameter in the assessment of mechanical and structural properties of materials. The generalized stacking energy (GSE) of SrO-and TiO 2 -terminated interfaces has been calculated for the g-surface projection 32 along o1004 and o1104 to assess the influence of the different chemical interactions in the different regions of the interface (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…1a,b) on the total energy and stability of the system. GSEs were computed using 30 Figure 3 illustrates the curves generated from GSE calculations for g-surface projections along o1004 and o1104 for both the SrO-and TiO 2 -terminated interfaces. In Fig.…”

Section: Resultsmentioning

confidence: 99%

Termination chemistry-driven dislocation structure at SrTiO3/MgO heterointerfaces

et al. 2014

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Exploiting the promise of nanocomposite oxides necessitates a detailed understanding of the dislocation structure at the interfaces, which governs diverse and technologically relevant properties. Here we report atomistic simulations demonstrating a strong dependence of the dislocation structure on the termination chemistry at the SrTiO 3 /MgO heterointerface. The SrO-and TiO 2 -terminated interfaces exhibit distinct nearest neighbour arrangements between cations and anions, leading to variations in local electrostatic interactions across the interface that ultimately dictate the dislocation structure. Networks of dislocations with different Burgers vectors and dislocation spacing characterize the two interfaces. These networks in turn influence the overall stability of and the behaviour of oxygen vacancies at the heterointerface, which will dictate vital properties such as mass transport at the interface. To date, the observed correlation between the dislocation structure and the termination chemistry at the interface has not been recognized, and offers novel avenues for fine-tuning oxide nanocomposites with enhanced functionalities.

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“…Compared with typical fcc-type chemical bonds, 37 it is noted that the rod-like directional bonds of the Mg matrix transform into fcc-type tetrahedrons with the formation of fault layers. 13,60,61 With the segregation of Gd atoms, bonding charge density of the basal plane increases significantly within the strong interaction region of Gd atoms, as highlighted by the blue dashed circles in Fig. 3.…”

Section: Resultsmentioning

confidence: 91%

Solid-Solution Hardening in Mg-Gd-TM (TM = Ag, Zn, and Zr) Alloys: An Integrated Density Functional Theory and Electron Work Function Study

Wang

Shang

Wang

et al. 2015

JOM

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The current work aims to reveal the effects of solute atoms (TM = Ag, Zn, and Zr) on the age hardening of Mg-Gd-based alloys via the density functional theory and electron work function (EWF) approaches. The 10H LPSO phases of Mg-Gd-TM alloys are selected as the model case due to the improved strength and ductility such long periodic stacking ordered precipitates (LPSOs) offer. The CALPHAD-modeling method is applied to predict the EWF in the ternary Mg-Gd-TM alloys. The obtained EWFs of these Mg alloys are shown to match well with previous experimental and theoretical results. Moreover, the variation of EWF in the ternary Mg-Gd-TM alloys is attributed to the structure contribution [i.e., the formation of face-centered cubic (fcc)-type fault layers] and the chemical effect of solute atoms (i.e., electron redistributions). With the knowledge of bonding charge density between the solute and solvent atoms, the present work provides insight into the correlations between the EWF and hardness of Mg-Gd-TM alloys.

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Effects of Alloying Elements on Stacking Fault Energies and Electronic Structures of Binary Mg Alloys: A First-Principles Study

Cited by 102 publications

References 57 publications

First-principles study of energy and atomic solubility of twinning-associated boundaries in hexagonal metals

First-principles study of energy and atomic solubility of twinning-associated boundaries in hexagonal metals

Termination chemistry-driven dislocation structure at SrTiO3/MgO heterointerfaces

Solid-Solution Hardening in Mg-Gd-TM (TM = Ag, Zn, and Zr) Alloys: An Integrated Density Functional Theory and Electron Work Function Study

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