Theoretical investigation of the Al–Cr–B orthorhombic ternary compounds

Nie, Li; Zhou, Wenbiao; Zhan, Yonghua

doi:10.1016/j.comptc.2013.07.035

Cited by 18 publications

(10 citation statements)

References 37 publications

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“…Figure A shows the band structure of Y 5 Si 2 B 8 . Similar to other transition metal borides, other MAB phases and MAX phases, valence and conduction bands overlap across the Fermi level, implying the presence of metallic bonding and metallic conductivity in Y 5 Si 2 B 8 . The finite states at Fermi level in the total density of states curve (Figure B) also indicate the presence of metallic bond in Y 5 Si 2 B 8 .…”

Section: Discussionmentioning

confidence: 71%

“…Polycrystalline bulk MoAlB was also prepared by Kota et al and relatively low hardness (10.6 GPa), good electrical and thermal conductivities, and excellent oxidation resistance were reported, which are very similar to those of MAX phases . Theoretically, metallic conductivity was predicted for Cr 2 AlB 2 , Cr 3 AlB 4 , Cr 4 AlB 6 and MoAlB . In addition, relatively low Yong's modulus was predicted for Cr 2 AlB 2 , Cr 3 AlB 4 , Cr 4 AlB 6 and MoAlB .…”

Section: Introductionmentioning

confidence: 90%

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Y₅Si₂B₈: A theoretically predicted new damage‐tolerant MAB phase with layered crystal structure

et al. 2018

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Layer structured MAB phases (M=transition metal, A=IIIA or IVA group element, B is boron) are promising ternary borides for high and ultrahigh‐temperature applications. Herein, a new MAB phase Y5Si2B8 consisting of alternative stacking of YB4 and Y3Si2 slabs along the [001] direction is investigated. Density functional theory (DFT) calculations on the electronic structure and chemical bonding reveal that this new MAB phase has diverse chemical bonding and properties similar to MAX phases. The strong covalent bonds in the two‐dimensional B network on (001) plane in the YB4 slab and between Si atoms on (002) plane in the Y3Si2‐slab warrant the high stiffness (Ex=288 GPa) of Y5Si2B8 in the ab plane and the weak Y2‐Si and Y1‐B2 bonds that connecting the YB4 and Y3Si2 slabs underpin the low Young's modulus in [001] direction (Ez=200 GPa). The low shear deformation resistance is due to the presence of the metallic bond and the weak bond within the B6 octahedral. The possible slip systems are {001}< 100> and {110}< 111> . Based on the low shear modulus (G = 104 GPa) and Pugh's ratio G/B, Y5Si2B8 is predicted as a damage tolerant MAB phase. Y5Si2B8 is also predicted electrically conductive and the conductivity is higher in directions parallel to ab plane. In addition, temperature‐dependent phonon and electron heat capacity are predicted based on the electron and phonon density of states analysis.

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Section: Discussionmentioning

confidence: 71%

Section: Introductionmentioning

confidence: 90%

Y₅Si₂B₈: A theoretically predicted new damage‐tolerant MAB phase with layered crystal structure

et al. 2018

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“…However, there are many correlations between Vickers hardness (H m ) and bulk, shear, Young's moduli, Poisson's ratio and G/B to obtain the value of micro-hardness parameter H, as following [51,52]:…”

Section: Tablementioning

confidence: 99%

Pressure effect on the structural, elastic, electronic and optical properties of the Zintl phase KAsSn, first principles study

Guechi

Merabet

Chegaar

et al. 2015

Journal of Alloys and Compounds

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“…It is reasonable to assume that the Cr–Al–B MAB phases would exhibit high oxidation resistance. Although some ground‐state properties including crystal structure, chemical bonding, hardness, and elastic properties were investigated in the previous work, no systematic study of these compounds has been reported. Density functional theory (DFT) is an efficient method to be used in ab initio electronic structure calculations of periodic systems .…”

Section: Introductionmentioning

confidence: 99%

Phase stability and weak metallic bonding within ternary‐layered borides CrAlB, Cr₂AlB₂, Cr₃AlB₄, and Cr₄AlB₆

Bai

et al. 2018

J Am Ceram Soc

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To explore the potential for use of the Cr–Al–B borides, Cr2AlB2, Cr3AlB4, and Cr4AlB6 as well as hypothetical CrAlB are investigated using density functional theory. In the CrAl(CrB2)n series strong covalent bonding is present between the B and Cr atoms with, significantly, much weaker metallic Cr–Al and B–Al bonds, suggesting similar unusual properties to the MAX phases. The relative stiffness of the weakest and strongest bonds hint at similar unusual properties to the MAX phases with superior damage tolerance expected for hypothetical CrAlB, as evidenced in the lowest Al1–Al2 bond stiffness. The layered nature and metallic bonding are expected to result in high fracture toughness and damage tolerance. Anisotropic compression is demonstrated, with the stiffest axes along the direction of the B–B zigzag‐/hexagonal‐chains and the softest axes determined by an interplay between the soft metallic interlayers and the rigid covalent bonds. In general the elastic moduli in CrAl(CrB2)n increase as a function of n, however, without the price of an increase in density.

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Theoretical investigation of the Al–Cr–B orthorhombic ternary compounds

Cited by 18 publications

References 37 publications

Y₅Si₂B₈: A theoretically predicted new damage‐tolerant MAB phase with layered crystal structure

Y₅Si₂B₈: A theoretically predicted new damage‐tolerant MAB phase with layered crystal structure

Pressure effect on the structural, elastic, electronic and optical properties of the Zintl phase KAsSn, first principles study

Phase stability and weak metallic bonding within ternary‐layered borides CrAlB, Cr₂AlB₂, Cr₃AlB₄, and Cr₄AlB₆

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Theoretical investigation of the Al–Cr–B orthorhombic ternary compounds

Cited by 18 publications

References 37 publications

Y5Si2B8: A theoretically predicted new damage‐tolerant MAB phase with layered crystal structure

Y5Si2B8: A theoretically predicted new damage‐tolerant MAB phase with layered crystal structure

Pressure effect on the structural, elastic, electronic and optical properties of the Zintl phase KAsSn, first principles study

Phase stability and weak metallic bonding within ternary‐layered borides CrAlB, Cr2AlB2, Cr3AlB4, and Cr4AlB6

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Y₅Si₂B₈: A theoretically predicted new damage‐tolerant MAB phase with layered crystal structure

Y₅Si₂B₈: A theoretically predicted new damage‐tolerant MAB phase with layered crystal structure

Phase stability and weak metallic bonding within ternary‐layered borides CrAlB, Cr₂AlB₂, Cr₃AlB₄, and Cr₄AlB₆