Nb4AlC3: A new compound belonging to the MAX phases

Hu, Chunfeng; Li, Fangzhi; Zhang, Jie; Wang, Jiemin; Wang, Jingyang; Zhou, Yanchun

doi:10.1016/j.scriptamat.2007.07.038

Cited by 156 publications

(113 citation statements)

References 20 publications

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“…Table 1. The calculated lattice parameters, a 0 and c 0 , and the internal structural parameters Z Nb1 , Z Nb2 and Z C , for Nb 4 AlC 3 , as determined from geometry at P=0 GPa, are given in Table 1 together with the available experimental and theoretical data. There is a good agreement between our results and the experimental ones [16]. The computed lattice constants a and c for Nb 4 AlC 3 deviate from the measured ones within 0.46 and 0.57%, respectively.…”

Section: Structural Propertiessupporting

confidence: 84%

“…For compounds with n=2, four members (the so-called 312 phases), were identified. When n is increased to 3, (the so-called 413 phases), four compounds were synthesized [13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

“…Recently Hu et al [16] reported that Nb 4 AlC 3 , a new compound belonging to the MAX phases, was discovered by annealing bulk Nb 2 AlC at 1700 • C. The crystal structure of Nb 4 AlC 3 was determined by combined X-ray diffraction and high-resolution transmission electron microscopy. It was reported that Nb 4 AlC 3 follows the Ti 4 AlN 3 -type crystal structure [17].…”

Section: Introductionmentioning

confidence: 99%

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First-principles study of structural, electronic and elastic properties of Nb4AlC3

Bouhemadou¹

2010

Braz. J. Phys.

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Using First-principles calculations, we have studied the structural, electronic and elastic properties of Nb 4 AlC 3 , a new compound belonging to the MAX phases. Geometrical optimization of the unit cell is in good agreement with the experimental data. The effect of high pressures, up to 20 GPa, on the lattice constants shows that the contractions are higher along the c-axis than along the a-axis. We have observed a quadratic dependence of the lattice parameters versus the applied pressure. The band structure shows that this compound is electrical conductor. The analysis of the site and momentum projected densities shows that bonding is due to Nb d-C p and Nb d-Al p hybridizations. The Nb d-C p bond is lower in energy and stiffer than Nb d-Al p bond. The elastic constants are calculated using the static finite strain technique. We derived the bulk and shear moduli, Young's modulus and Poisson's ratio for ideal polycrystalline Nb 4 AlC 3 aggregate. We estimated the Debye temperature of Nb 4 AlC 3 from the average sound velocity. This is the first quantitative theoretical prediction of the elastic properties of Nb 4 AlC 3 compound, and it still awaits experimental confirmation.

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Section: Structural Propertiessupporting

confidence: 84%

“…For compounds with n=2, four members (the so-called 312 phases), were identified. When n is increased to 3, (the so-called 413 phases), four compounds were synthesized [13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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First-principles study of structural, electronic and elastic properties of Nb4AlC3

Bouhemadou¹

2010

Braz. J. Phys.

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“…These results also indicate that the order of the MAX phase (211, 312, [241] can be synthesized in relatively phase-pure form by annealing of Ti 2 AlC, Ta 2 AlC, and Nb 2 AlC, respectively, at temperatures of 1400-1700 C, which leads to an inter-conversion to higher-order MAX phases.…”

Section: Temperature Ranges For Max-phase Synthesismentioning

confidence: 58%

“…and Hu et al [251,252]), Nb 4 AlC 3 (discovered by Hu et al [241]), the solid solution (V,Cr) 4 [47] have been reported.…”

Section: Ion Bombardment Effectsmentioning

confidence: 89%

The M+1AX phases: Materials science and thin-film processing

et al. 2010

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This article is a critical review of the M n+1 AX n phases ("MAX phases", where n =1, 2, or 3) from a materials science perspective. MAX phases are a class of hexagonal-structure ternary carbides and nitrides ("X") of a transition metal ("M") and an A-group element. The most well known are Ti 2 AlC, Ti 3 SiC 2 , and Ti 4 AlN 3 . There are ~60 MAX phases with at least 9 discovered in the last five years alone. What makes the MAX phases fascinating and potentially useful is their remarkable combination of chemical, physical, electrical, and mechanical properties, which in many ways combine the characteristics of metals and ceramics. For example, MAX phases are typically resistant to oxidation and corrosion, elastically stiff, but at the same time they exhibit high thermal and electrical conductivities and are machinable. These properties stem from an inherently nanolaminated crystal structure, with M n+1 X n slabs intercalated with pure A-element layers. The research on MAX phases has been accelerated by the introduction of thin-film processing methods.Magnetron sputtering and arc deposition have been employed to synthesize single-crystal material by epitaxial growth, which enables studies of fundamental materials properties. However, the surface-initiated decomposition of M n+1 AX n thin films into MX compounds at temperatures of 1000-1100 °C is much lower than the decomposition temperatures typically reported for the corresponding bulk material. We also review the prospects for low-temperature synthesis, which is essential for deposition of MAX phases onto technologically important substrates. While deposition of MAX phases from the archetypical Ti-Si-C and Ti-Al-N systems typically require synthesis temperatures of ~800 °C, recent results have demonstrated that V 2 GeC and Cr 2 AlC can be deposited at ~450 °C. Also, thermal spray of Ti 2 AlC powder has been used to produce thick coatings. We further treat progress in the use of first-principles calculations for predicting hypothetical MAX phases and their properties. Together with advances in processing and materials 3 analysis, this progress has led to recent discoveries of numerous new MAX phases such as Ti 4 SiC 3 , Ta 4 AlC 3 , and Ti 3 SnC 2 . Finally, important future research directions are discussed. These include charting the unknown regions in phase diagrams to discover new equilibrium and metastable phases, as well as research challenges in understanding their physical properties, such as the effects of anisotropy, impurities, and vacancies on the electrical properties, and unexplored properties such as superconductivity, magnetism, and optics. 4

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