Chemical bonding and mechanical properties of M2AC (M = Ti, V, Cr, A = Al, Si, P, S) ceramics from first-principles investigations

MAX-phase carbides (M is an early transition metal, A is an A-group element) exhibit an interesting bonding characteristic of alternative stacking of strong M–C bonds and relatively weak M–A bonds in one direction. In the present first-principles total energy calculations, we establish the relationship between mechanical properties and electronic structure for ternary M2AC (M = Ti, V, Cr, A = Al, Si, P, S) carbides. By systematically tuning elements on the M and A sites, pronounced enhancements of bulk modulus, elastic stiffness, and ideal shear strength are achieved in V-containing V2AC (A = Al, Si, P, and S) carbides. It is suggested that tailoring on the A site is more efficient than on the M site in strengthening the mechanical properties of studied serial carbides. The results highlight a general trend for tailor-made mechanical properties of ternary M2AC carbides by control of chemical bonding.

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A first principles investigation on the structural, elastic, and mechanical properties of MAX phase M3AlC2 (M= Ta, Ti, V) as a function of pressure

Computational Condensed Matter ◽

10.1016/j.cocom.2021.e00638 ◽

2022 ◽

pp. e00638

Author(s):

Wutthigrai Sailuam ◽

Ittipon Fongkaew ◽

Sukit Limpijumnong ◽

Kanoknan Phacheerak

Keyword(s):

Mechanical Properties ◽

First Principles ◽

Max Phase

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Effects of Doped Elements (Si, Cr, W and Nb) on the Stability, Mechanical Properties and Electronic Structures of MoAlB Phase by the First-Principles Calculation

Materials ◽

10.3390/ma13194221 ◽

2020 ◽

Vol 13 (19) ◽

pp. 4221

Author(s):

Yongxin Jian ◽

Zhifu Huang ◽

Yu Wang ◽

Jiandong Xing

Keyword(s):

Mechanical Properties ◽

Chemical Bonding ◽

First Principles ◽

Electronic Structures ◽

Density Functional ◽

Formation Enthalpy ◽

First Principles Calculation ◽

Elemental Doping ◽

The Stability ◽

W Doping

First-principles calculations based on density functional theory (DFT) have been performed to explore the effects of Si, Cr, W, and Nb elements on the stability, mechanical properties, and electronic structures of MoAlB ternary boride. The five crystals, with the formulas of Mo4Al4B4, Mo4Al3SiB4, Mo3CrAl4B4, Mo3WAl4B4, and Mo3NbAl4B4, have been respectively established. All the calculated crystals are thermodynamically stable, according to the negative cohesive energy and formation enthalpy. By the calculation of elastic constants, the mechanical moduli and ductility evolutions of MoAlB with elemental doping can be further estimated, with the aid of B/G and Poisson’s ratios. Si and W doping cannot only enhance the Young’s modulus of MoAlB, but also improve the ductility to some degree. Simultaneously, the elastic moduli of MoAlB are supposed to become more isotropic after Si and W addition. However, Cr and Nb doping plays a negative role in ameliorating the mechanical properties. Through the analysis of electronic structures and chemical bonding, the evolutions of chemical bondings can be disclosed with the addition of dopant. The enhancement of B-B, Al/Si-B, and Al/Si-Mo bondings takes place after Si substitution, and W addition apparently intensifies the bonding with B and Al. In this case, the strengthening of chemical bonding after Si and W doping exactly accounts for the improvement of mechanical properties of MoAlB. Additionally, Si doping can also improve the Debye temperature and melting point of the MoAlB crystal. Overall, Si element is predicted to be the optimized dopant to ameliorate the mechanical properties of MoAlB.

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Dyeing and Mechanical Properties of Cotton Modified for Cationic Dyes with Hydrophobic and Acidic Groups

Textile Research Journal ◽

10.1177/004051759206200303 ◽

1992 ◽

Vol 62 (3) ◽

pp. 135-139 ◽

Cited By ~ 2

Author(s):

Kazuhiko Fukatsu

Keyword(s):

Mechanical Properties ◽

General Trend ◽

Breaking Load ◽

Cationic Dyes ◽

Superior Performance ◽

Chemically Modified ◽

Basic Studies ◽

The Relationship ◽

Sulfonic Acid Groups ◽

Selection Of

Basic studies define the relationship between dyeability for cationic dyes and mechanical properties of chemically modified cotton fabric. Introduction of benzoyl and sulfonic acid groups provides either satisfactory dyeability for cationic dyes or color-fastness, and mechanical properties are reported as a function of the benzoate degree of substitution value. The general trend is toward increased breaking load and bending stiffness and decreased wrinkle recovery for the chemically modified fabrics, but within this trend there is latitude for selection of the degree of substituent groups to provide superior performance.

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Vacancy-induced elastic properties and hardness of CrB4: A DFT calculation

International Journal of Modern Physics B ◽

10.1142/s0217979217500965 ◽

2017 ◽

Vol 31 (13) ◽

pp. 1750096 ◽

Cited By ~ 1

Author(s):

Yong Pan ◽

Song Chen ◽

Yuanhua Lin

Keyword(s):

Mechanical Properties ◽

Dft Calculation ◽

Covalent Bond ◽

Elastic Stiffness ◽

First Principle ◽

Triangular Pyramid ◽

First Principle Calculations ◽

3D Network ◽

Metal Borides ◽

The Relationship

Vacancy plays a crucial role in mechanical properties of transition metal borides (TMBs). However, the influence of vacancy on hardness of TMBs is unknown. In this paper, the relationship between boron vacancy and mechanical properties of CrB4 is investigated by first-principle calculations. Two different vacancies including boron monovacancy (MV) and boron bivacancy (BV) are considered. We find that CrB4 with boron MV is more stable than that of boron BV. The removed atom weakens the deformation resistances, and reduces the elastic stiffness and hardness. The calculated shear modulus, Young’s modulus and theoretical hardness of boron MV are larger than that of boron BV. The reason is that the removed atom weakens the localized hybridization between B and B atoms, and damages the 3D-network B–B covalent bond. However, the bulk modulus of B[Formula: see text] is slightly larger than that of perfect CrB4. This reason is attributed to the formation of triangular pyramid bonding in B[Formula: see text] vacancy.

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Electronic structure and elastic properties of AgZn under pressure from first-principles calculations

Canadian Journal of Physics ◽

10.1139/cjp-2015-0684 ◽

2016 ◽

Vol 94 (3) ◽

pp. 328-333

Author(s):

Yasemin Ö. Çiftci

Keyword(s):

Density Of States ◽

First Principles ◽

Density Functional ◽

Elastic Stiffness ◽

Distribution Analysis ◽

First Principles Calculations ◽

Generalized Gradient ◽

Functional Theory ◽

B2 Structure ◽

Bonding Characteristic

In this study, the structural, elastic, electronic, and bonding nature of AgZn in B2 structure under pressure have been investigated by performing first principles calculations using density functional theory. The exchange-correlation potentials were treated within the generalized gradient approximation. The calculated quantities agree well with the available results. The electronic properties, such as band structure and density of states reveal that AgZn is metallic in nature with a large overlap at the Fermi level. The single-crystal elastic stiffness constants of AgZn are investigated using the stress–strain method. Present results for elastic constants show that AgZn is mechanically stable. The chemical bonding is interpreted by calculating the density of states and electron density distribution analysis. AgZn has ionic bonding characteristic.

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Mechanical properties and chemical bonding of the Os–B system: A first-principles study

Acta Materialia ◽

10.1016/j.actamat.2012.04.015 ◽

2012 ◽

Vol 60 (10) ◽

pp. 4208-4217 ◽

Cited By ~ 28

Author(s):

Zong-Wei Ji ◽

Chao-Hao Hu ◽

Dian-Hui Wang ◽

Yan Zhong ◽

Jiong Yang ◽

...

Keyword(s):

Mechanical Properties ◽

Chemical Bonding ◽

First Principles ◽

First Principles Study ◽

System A

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Phase stability, chemical bonding and mechanical properties of titanium nitrides: a first-principles study

Physical Chemistry Chemical Physics ◽

10.1039/c5cp00156k ◽

2015 ◽

Vol 17 (17) ◽

pp. 11763-11769 ◽

Cited By ~ 61

Author(s):

Shuyin Yu ◽

Qingfeng Zeng ◽

Artem R. Oganov ◽

Gilles Frapper ◽

Litong Zhang

Keyword(s):

Mechanical Properties ◽

Crystal Structures ◽

Phase Stability ◽

Chemical Bonding ◽

First Principles ◽

Titanium Nitrides ◽

First Principles Study ◽

N Compounds

New crystal structures of Ti–N compounds: (a) Immm-Ti3N2 at 0 GPa, (b) C2/m-Ti4N3 at 0 GPa, (c) C2/m-Ti6N5 at 0 GPa, and (d) Cmcm-Ti2N at 60 GPa.

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The Mechanical Properties and Elastic Anisotropy of η’-Cu6Sn5 and Cu3Sn Intermetallic Compounds

Crystals ◽

10.3390/cryst11121562 ◽

2021 ◽

Vol 11 (12) ◽

pp. 1562

Author(s):

Chao Ding ◽

Jian Wang ◽

Tianhan Liu ◽

Hongbo Qin ◽

Daoguo Yang ◽

...

Keyword(s):

Mechanical Properties ◽

High Temperature ◽

Intermetallic Compound ◽

Intermetallic Compounds ◽

First Principles ◽

Elastic Anisotropy ◽

First Principles Calculations ◽

Anisotropic Behavior ◽

Ductile Materials ◽

The Relationship

Full intermetallic compound (IMC) solder joints present fascinating advantages in high-temperature applications. In this study, the mechanical properties and elastic anisotropy of η’-Cu6Sn5 and Cu3Sn intermetallic compounds were investigated using first-principles calculations. The values of single-crystal elastic constants, the elastic (E), shear (G), and bulk (B) moduli, and Poisson’s ratio (ν) were identified. In addition, the two values of G/B and ν indicated that the two IMCs were ductile materials. The elastic anisotropy of η’-Cu6Sn5 was found to be higher than Cu3Sn by calculating the universal anisotropic index. Furthermore, an interesting discovery was that the above two types of monocrystalline IMC exhibited mechanical anisotropic behavior. Specifically, the anisotropic degree of E and B complied with the following relationship: η’-Cu6Sn5 > Cu3Sn; however, the relationship was Cu3Sn > η’-Cu6Sn5 for the G. It is noted that the anisotropic degree of E and G was similar for the two IMCs. In addition, the anisotropy of the B was higher than the G and E, respectively, for η’-Cu6Sn5; however, in the case of Cu3Sn, the anisotropic degree of B, G, and E was similar.

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An Investigation on Substitution of Ag Atoms for Al or Ti Atoms in the Ti2AlC MAX Phase Ceramic Based on First-Principles Calculations

Materials ◽

10.3390/ma14227068 ◽

2021 ◽

Vol 14 (22) ◽

pp. 7068

Author(s):

Guochao Wang ◽

Jiahe Zhou ◽

Weijian Chen ◽

Jianguo Yang ◽

Jie Zhang ◽

...

Keyword(s):

Electrical Conductivity ◽

Fermi Level ◽

First Principles ◽

First Principles Calculation ◽

Max Phase ◽

Lattice Stability ◽

Substitution Ratio ◽

New Perspective ◽

The Stability ◽

Bonding Characteristic

The present work introduced first-principles calculation to explore the substitution behavior of Ag atoms for Al or Ti atoms in the Ti2AlC MAX phase ceramic. The effect of Ag substitution on supercell parameter, bonding characteristic, and stability of the Ti2AlC was investigated. The results show that for the substitution of Ag for Al, the Al-Ti bond was replaced by a weaker Ti-Ag bond, decreasing the stability of the Ti2AlC. However, the electrical conductivity of the Ti2AlC was enhanced after the substitution because of the contribution of Ag 4d orbital electrons toward the density of states (DOS) at the Fermi level coupled with the filling of Ti d orbital electrons. For the substitution of Ag for Ti, new bonds, such as Ag-Al bond, Ag-C bond, Al-Al bond, Ti-Ti anti-bond, and C-C anti-bond were generated in the Ti2AlC. The Ti-Ti anti-bond was strengthened as well as the number of C-C anti-bond was increased with increasing the substitution ratio of Ag for Ti. Similar to the substitution of Ag for Al, the stability of the Ti2AlC also decreased because the original Al-Ti bond became weaker as well as the Ti-Ti and C-C anti-bonds were generated during the substitution of Ag for Ti. Comparing with the loss of Ti d orbital electrons, Ag 4d orbits contributed more electrons to the DOS at the Fermi level, improving the electrical conductivity of the Ti2AlC after substitution. Based on the calculation, the substitution limit of Ag for Al or Ti was determined. At last, the substitution behavior of Ag for Al or Ti was compared to discriminate that Ag atoms would tend to preferentially substitute for Ti atoms in Ti2AlC. The current work provides a new perspective to understand intrinsic structural characteristic and lattice stability of the Ti2AlC MAX phase ceramic.

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