Site Preference and Elastic Properties of 3d Transition Metals Alloying Addition in Ductility YAg Alloys

2012 ◽  
Vol 535-537 ◽  
pp. 1000-1004
Author(s):  
Yu Rong Wu ◽  
Wang Yu Hu ◽  
Long Shan Xu

First-principles supercell calculations based on density functional theory were performed to study the site preference behavior and elastic properties of 3d (Ti-Cu) transition-metal elements in B2 ductility YAg alloy. It is found that Ti occupies the Y sublattice, while V, Cr, Co, Fe, Ni and Cu tend to substitute for Ag site. All alloying elements can decrease the lattice parameters of Y8Ag8, among which Y7Ag8Ti shows the largest change. Furthermore, the calculated elastic constants show that Cr, Fe, Co and Cu can improve the ductility of YAg alloy, and Y8Ag7Fe presents the most ductility among these alloy, while Ti and Ni alloying elements reduce the ductility of YAg alloy, especially, V transforms ductile into brittle for YAg alloy. In addition, both V and Ni can increase the hardness of YAg alloy, and Y8Ag7V is harder than Y8Ag7Ni.

2012 ◽  
Vol 472-475 ◽  
pp. 1397-1401
Author(s):  
Yu Rong Wu ◽  
Wang Yu Hu ◽  
Long Shan Xu

First-principles supercell calculations, which are based on density functional theory, were performed to study the site preference behavior and elastic properties of 5d (Hf-Au) transition-metal elements in B2 ductility YAg alloy. It is found that all alloying elements Hf, Ta, W, Re, Os, Ir, Pt and Au occupy the Y sub-lattice. Micro-alloying transition metals W, Re, Os, Ir and Pt decrease the lattice parameters of Y8Ag8 except Hf, Ta and Au, among which Y8Ag7Hf shows the largest variance. Furthermore, the calculated elastic constants show that Hf, Ta, W, Re, Os, Pt and Au improve the ductility of YAg alloy, and Y8Ag7Hf presents the most ductility among these alloy, while Ir transforms ductile into brittle for YAg alloy. In addition, Os alloying element increases the hardness of YAg alloy.


2008 ◽  
Vol 19 (08) ◽  
pp. 1269-1275 ◽  
Author(s):  
YANLING LI ◽  
ZHI ZENG

The elastic properties of rutile transition metal dioxides XO2 ( X = Ru , Rh , Os , and Ir ) are investigated using first-principles calculations based on density functional theory. Elastic constants, bulk modulus, shear modulus, and Young's modulus as well as Possion ratio are given. OsO 2 and IrO 2 show strong incompressibility. The hardness estimated for these dioxides shows that they are not superhard solids. The obtained Debye temperatures are comparative to those of transition metal dinitrides or diborides.


Nanoscale ◽  
2020 ◽  
Author(s):  
Shashikant Kumar ◽  
David Codony ◽  
Irene Arias ◽  
Phanish Suryanarayana

We study the flexoelectric effect in fifty-four select atomic monolayers using ab initio Density Functional Theory (DFT). Specifically, considering representative materials from each of Group III monochalcogenides, transition metal dichalcogenides...


Author(s):  
Yogeshwaran Krishnan ◽  
Sateesh Bandaru ◽  
Niall J. English

A series of transition-metal-doped Fe1−xMxCo(PO4)4(010) and Fe3Co1−xMx(PO4)4(010) electro-catalyst surfaces (with M = Mn, Os, Ru, Rh and Ir) have been modelled via density-functional theory (DFT) to gauge their oxygen-evolution reactions (OER).


2019 ◽  
Vol 21 (45) ◽  
pp. 25397-25405
Author(s):  
Shukai Yao ◽  
Pilsun Yoo ◽  
Peilin Liao

First principles density functional theory calculations were performed to identify transition metal perovskites CaFeO3, SrFeO3, BaFeO3 and SmMnO3 as promising candidates with large band gap opening upon hydrogen doping.


2010 ◽  
Vol 25 (12) ◽  
pp. 2317-2324 ◽  
Author(s):  
Hui-Yuan Wang ◽  
Wen-Ping Si ◽  
Shi-Long Li ◽  
Nan Zhang ◽  
Qi-Chuan Jiang

The formation enthalpy, electronic structures, and elastic moduli of the intermetallic compound Ti5Si3 with substitutions Zr, V, Nb, and Cr are investigated by using first-principles methods based on the density-functional theory. Our calculation shows that the site occupancy behaviors of alloying elements in Ti5Si3, determined by their atom radius, are consistent with the available experimental observations. Furthermore, using the Voigt–Reuss–Hill (VRH) approximation method, we obtained the bulk modulus B, shear modulus G, and the Young’s modulus E. Among these four substitutions, the V, Nb, and Cr substitutions can improve the ductility of Ti5Si3 effectively, while Zr substitution has little effect on the elastic properties of Ti5Si3. The elastic property variations of Ti5Si3 due to different substitutions are found to be correlated with the Me4d–Me4d antibonding and the strengthened Me4d–Si bonding in the solids.


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