Structural and optical properties of the recently synthesized (Zr3−x Ti x )AlC2 MAX phases

Hadi, M. A.; Panayiotatos, Y.; Chroneos, Alexander

doi:10.1007/s10854-016-5933-z

Cited by 27 publications

(11 citation statements)

References 57 publications

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“…On the other hand, (Zr 1-x ,Ti x ) 3 AlC 2 MAX phases were recently claimed to have been successfully synthesized, but the results of that study have not yet been published. 13 Solid solutions reported to contain Ti, Zr, Al and C include: (Ti,M) 2 AlC with M = V, Nb, Ta, Cr, [14][15][16][17] (Nb,Zr) 2 AlC, 15,18 (Ti,V) 3 AlC 2 , 18 (Ti,Nb) 4 AlC 3 , 19 and (Nb,Zr) 4 AlC 3 . 20,21 In this study, Ti was added to the Zr-Al-C system in an attempt to synthesize (Zr 1-x ,Ti x ) 3 AlC 2 (ZT312) and (Zr 1-x ,Ti x ) 2 AlC (ZT211) MAX phase solid solutions.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of MAX Phases in the Zr-Ti-Al-C System

et al. 2017

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This study reports on the synthesis and characterization of MAX phases in the (Zr,Ti)AlC system. The MAX phases were synthesized by reactive hot pressing and pressureless sintering in the 1350-1700 °C temperature range. The produced ceramics contained large fractions of 211 and 312 (n = 1, 2) MAX phases, while strong evidence of a 413 (n = 3) stacking was found. Moreover, (Zr,Ti)C, ZrAl, ZrAl, and ZrAl were present as secondary phases. In general, the lattice parameters of the hexagonal 211 and 312 phases followed Vegard's law over the complete Zr-Ti solid solution range, but the 312 phase showed a non-negligible deviation from Vegard's law around the (Zr,Ti)AlC stoichiometry. High-resolution scanning transmission electron microscopy combined with X-ray diffraction demonstrated ordering of the Zr and Ti atoms in the 312 phase, whereby Zr atoms occupied preferentially the central position in the close-packed MX octahedral layers. The same ordering was also observed in 413 stackings present within the 312 phase. The decomposition of the secondary (Zr,Ti)C phase was attributed to the miscibility gap in the ZrC-TiC system.

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Section: Introductionmentioning

confidence: 99%

Synthesis of MAX Phases in the Zr-Ti-Al-C System

et al. 2017

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“…The recent discovery of a magnetic MAX phase has extended the list of interesting properties of MAX family [7]. To date, a large number of MAX phase compounds have been synthesized [8][9][10][11][12][13][14][15][16][17] and their physical properties have also been studied [18][19][20][21][22][23][24][25][26][27]. Very recently, Lapauw et al has synthesized Hf 3 AlC 2 [28], which is the first member of 312 MAX phases in the Hf-Al-C system.…”

Section: Introductionmentioning

confidence: 99%

First hafnium-based MAX phase in the 312 family, Hf3AlC2: A first-principles study

Roknuzzaman

Hadi

Ali

et al. 2017

Journal of Alloys and Compounds

119

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The ground state physical properties of the newly synthesized 312 MAX compound, Hf 3 AlC 2 have been investigated using the first-principles density functional theory (DFT). The optimized unit cell parameters show good agreement with the experimental values. The calculated elastic constants and phonon dispersion confirm the mechanical and dynamical stabilities of this new compound. High bulk modulus, combined with low shear resistance and low Vickers hardness, indicates good machinability of Hf 3 AlC 2 , as expected for a metallic compound. On the other hand, significant stiffness due to large Young's modulus as well as the brittle nature according to the calculated Pugh's and Poison's ratios and Cauchy pressure are comparable to that of a ceramic. The present calculations show that Hf 3 AlC 2 is elastically and optically anisotropic. The chemical bonding in Hf 3 AlC 2 consists of a mixture of metallic, covalent and ionic contributions. The calculated Fermi surface contains quasi-twodimensional topology, which indicates possible superconductivity of Hf 3 AlC 2 . The new phase Hf 3 AlC 2 may also be a promising thermal barrier coating (TBC) material. The calculated enthalpy and entropy are found to increase with temperature above 100 K though a decrease is observed for the free energy.

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“…The strain can affect the imaginary part of the dielectric function and further affect the optical properties of semiconductor materials. [42][43][44][45][46] For example, Cakir et al [8] thought that strain has a significant effect on the optical properties and can tune the optical band gap of monolayer black phosphorus from 0.38 eV to 2.07 eV. Yang et al [30] found that strain greatly changed the optical properties of ReSe 2 .…”

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confidence: 99%

Strain‐tunable electronic properties and optical properties of Hf₂CO₂ MXene

Zhang

et al. 2020

Int J of Quantum Chemistry

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Two-dimensional materials have been extensively applied because of their unusual electronic, mechanical, and optical properties. In this paper, the electronic structure and optical properties of Hf 2 CO 2 MXene under biaxial and uniaxial strains are investigated by the Heys-Scuseria-Ernzerhof (HSE06) method. Monolayer Hf 2 CO 2 can sustain stress up to 6.453 N/M for biaxial strain and 3.072 N/M for uniaxial strain. Monolayer Hf 2 CO 2 undergoes the transition from semiconductor to metal under −12% strain whether it is under biaxial or uniaxial strain. With the increasing biaxial compressive strain, the blue shift of Hf-d, O-p, and C-p orbitals in valence band maximum results in the metallization of monolayer Hf 2 CO 2 , while the red shift of Hf-d and O-p orbitals in conduction band minimum results in the metallization of monolayer Hf 2 CO 2 with increasing uniaxial compressive strain. The analysis of optical properties indicates that uniaxial strain weakens the reflectivity and refractive index of monolayer Hf 2 CO 2 in the visible-light range. In addition, the effective mass and the charge distribution under biaxial and uniaxial strains are also explored.

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Structural and optical properties of the recently synthesized (Zr3−x Ti x )AlC2 MAX phases

Cited by 27 publications

References 57 publications

Synthesis of MAX Phases in the Zr-Ti-Al-C System

Synthesis of MAX Phases in the Zr-Ti-Al-C System

First hafnium-based MAX phase in the 312 family, Hf3AlC2: A first-principles study

Strain‐tunable electronic properties and optical properties of Hf₂CO₂ MXene

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Structural and optical properties of the recently synthesized (Zr3−x Ti x )AlC2 MAX phases

Cited by 27 publications

References 57 publications

Synthesis of MAX Phases in the Zr-Ti-Al-C System

Synthesis of MAX Phases in the Zr-Ti-Al-C System

First hafnium-based MAX phase in the 312 family, Hf3AlC2: A first-principles study

Strain‐tunable electronic properties and optical properties of Hf2CO2 MXene

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Strain‐tunable electronic properties and optical properties of Hf₂CO₂ MXene