OS0115 Effects of Solute Atoms on Twin Boundaries and Surfaces of Mg Alloys by First-principles Calculations

2014 ◽  
Vol 2014 (0) ◽  
pp. _OS0115-1_-_OS0115-2_
Author(s):  
Daisuke MATSUNAKA ◽  
Yoji MATSUNAKA
Keyword(s):  
First Principles ◽  
Mg Alloys ◽  
First Principles Calculations ◽  
Twin Boundaries ◽  
Solute Atoms

Grain Refining Behavior of Zr, Al2Y and Al4C3 Particles in Magnesium Alloys by the First-Principles Calculations

2015 ◽  
Vol 816 ◽  
pp. 370-374
Author(s):  
Jun Ling Pan ◽  
Qiu Ming Peng ◽  
Jian Xin Guo ◽  
Hui Li
Keyword(s):  
Mechanical Properties ◽  
Structural Optimization ◽  
Magnesium Alloys ◽  
Density Of States ◽  
Adsorption Energy ◽  
First Principles ◽  
Adsorption Process ◽  
Mg Alloys ◽  
Grain Refining ◽  
First Principles Calculations

Grain refining is one of the most important issues in the applications of Mg alloys, which directly determines mechanical properties and deformability. Therefore the understanding of grain refining mechanism during solidification will be benefit to develop new grain refiners. Herein refining role was elucidated by the first principles calculations based on adsorption behavior of a Mg atom on the closest-packed planes of grain refiners (Zr (001), Al2Y(311) and Al4C3(102)). Taking into account different sites, the site with the maximum adsorption energy value generally corresponded to the most possible location. The adsorption energy results show that the possible refining turn follows Al4C3(102)>Zr (001)>Al2Y(311). Meanwhile, the structural optimization confirmed that the Mg atom connected with two C atoms on the top of zig-zag plane of Al4C3(102), three Zr atoms at the hcp position on Zr (001), and two Y atoms and one Al atom at the bottom of zig-zag plane of Al2Y(311). The density of states revealed that the variation of d-orbital electrons of Mg atom became apparent during adsorption process. The values of Mulliken charges were 0.898 e in Al4C3(102), 0.410 e in Zr (001) and 0.245 e in Al2Y(311), respectively. This tendency agrees well with the previous experimental results. It indicates the adsorption energy on the closest-packed planes can be regarded as a prerequisite to select new grain refiners for Mg alloys in future.

Origin of dramatic oxygen solute strengthening effect in titanium

Science ◽  
2015 ◽  
Vol 347 (6222) ◽  
pp. 635-639 ◽  
Author(s):  
Qian Yu ◽  
Liang Qi ◽  
Tomohito Tsuru ◽  
Rachel Traylor ◽  
David Rugg ◽  
...  
Keyword(s):  
First Principles ◽  
Dislocation Core ◽  
Strengthening Effect ◽  
First Principles Calculations ◽  
Screw Dislocations ◽  
Elastic Fields ◽  
Transmission Electron ◽  
Short Range Repulsion ◽  
Solute Atoms ◽  
Solute Strengthening

Structural alloys are often strengthened through the addition of solute atoms. However, given that solute atoms interact weakly with the elastic fields of screw dislocations, it has long been accepted that solution hardening is only marginally effective in materials with mobile screw dislocations. By using transmission electron microscopy and nanomechanical characterization, we report that the intense hardening effect of dilute oxygen solutes in pure α-Ti is due to the interaction between oxygen and the core of screw dislocations that mainly glide on prismatic planes. First-principles calculations reveal that distortion of the interstitial sites at the screw dislocation core creates a very strong but short-range repulsion for oxygen that is consistent with experimental observations. These results establish a highly effective mechanism for strengthening by interstitial solutes.

scholarly journals Unusual solute segregation phenomenon in coherent twin boundaries

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Cong He ◽  
Zhiqiao Li ◽  
Houwen Chen ◽  
Nick Wilson ◽  
Jian-Feng Nie
Keyword(s):  
Twin Boundary ◽  
Chemical Bonding ◽  
Electronic Configuration ◽  
Solute Segregation ◽  
Mg Alloys ◽  
Coherent Twin Boundary ◽  
Twin Boundaries ◽  
Segregation Phenomenon ◽  
Solute Atoms ◽  
Engineering Alloys

AbstractInterface segregation of solute atoms has a profound effect on properties of engineering alloys. The occurrence of solute segregation in coherent twin boundaries (CTBs) in Mg alloys is commonly considered to be induced by atomic size effect where solute atoms larger than Mg take extension sites and those smaller ones take compression sites in CTBs. Here we report an unusual solute segregation phenomenon in a group of Mg alloys—solute atoms larger than Mg unexpectedly segregate to compression sites of {10$$\overline 1$$ 1 ¯ 1} fully coherent twin boundary and do not segregate to the extension or compression site of {10$$\overline 1$$ 1 ¯ 2} fully coherent twin boundary. We propose that such segregation is dominated by chemical bonding (coordination and solute electronic configuration) rather than elastic strain minimization. We further demonstrate that the chemical bonding factor can also predict the solute segregation phenomena reported previously. Our findings advance the atomic-level understanding of the role of electronic structure in solute segregation in fully coherent twin boundaries, and more broadly grain boundaries, in Mg alloys. They are likely to provide insights into interface boundaries in other metals and alloys of different structures.

Effects of distributions of Al, Zn and Al+Zn atoms on the strengthening potency of Mg alloys: A first-principles calculations

2015 ◽  
Vol 104 ◽  
pp. 23-28 ◽  
Author(s):  
Cheng Wang ◽  
Tian-Long Huang ◽  
Hui-Yuan Wang ◽  
Xue-Na Xue ◽  
Qi-Chuan Jiang
Keyword(s):  
First Principles ◽  
Mg Alloys ◽  
First Principles Calculations

A DFT study of the adsorption of short peptides on Mg and Mg-based alloy surfaces

2018 ◽  
Vol 20 (5) ◽  
pp. 3602-3607 ◽  
Author(s):  
Zhe Fang ◽  
Jianfeng Wang ◽  
Shijie Zhu ◽  
Xiaofan Yang ◽  
Yu Jia ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
First Principles ◽  
Density Functional ◽  
Van Der Waals ◽  
Mg Alloys ◽  
Dft Study ◽  
Short Peptides ◽  
First Principles Calculations ◽  
Functional Theory ◽  
P Adsorption

Adsorption of short peptides, including three dipeptides: Arg–Gly, Gly–Asp, Arg–Asp, and one tripeptide RGD, on the surfaces of Mg and Mg alloys (Mg–Zn, Mg–Y, and Mg–Nd), was studied using first-principles calculations based on density functional theory (DFT), considering van der Waals (vdW) correction.

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