Processing and characterization of Ti2AlC, Ti2AlN, and Ti2AlC0.5N0.5

Barsoum, Michel W.; El‐Raghy, T.; Ali, Mohammad

doi:10.1007/s11661-006-0243-3

Cited by 519 publications

(300 citation statements)

References 25 publications

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“…For example, bulk Ti 2 AlC 0.5 N 0.5 has been reported [74] to be significantly harder and stiffer than either of its end members Ti 2 AlC and Ti 2 AlN, and there may be other ratios of C and N with even better properties. A continues series of solid solutions, Ti 2 AlC 0.8-x N x , where x = 0-0.8, was reported by Pietzka and Schuster [75].…”

Section: Site Solid Solutionsmentioning

confidence: 99%

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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Section: Site Solid Solutionsmentioning

confidence: 99%

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

et al. 2010

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“…[19][20][21] The ideal tensile strengths change slightly and show no obvious difference between binary and ternary compounds. On the other hand, the ideal shear strength shows a similar trend with hardness.…”

Section: A Ideal Stress-strain Curvesmentioning

confidence: 99%

Deformation modes and ideal strengths of ternary layeredTi2AlCandTi2
Liao
¹
,
Wang
²
,
Zhou
³

2006
Phys. Rev. B

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Deformation and failure modes were studied for Ti 2 AlC and Ti 2 AlN by deforming the materials from elasticity to structural instability using the first-principles density functional calculations. We found that the TiC 0.5 / TiN 0.5 slabs remain structurally stable under deformations, whereas the weak Ti-Al bonds accommodate deformation by softening and breaking at large strains. The structural stability of the ternary compound is determined by the strength of Ti-Al bond, which is demonstrated to be less resistive to shear deformation than to tension. The ideal stress-strain relationships of ternary compounds are presented and compared with those of the binary materials, TiC and TiN, respectively. For Ti 2 AlC and Ti 2 AlN, their ideal tensile strengths are comparable to those of the binary counterparts, while the ideal shear strengths yield much smaller values. Based on electronic structure analyses, the low shear deformation resistance is well interpreted by the response of weak Ti-Al bonds to shear deformations. We propose that the low shear strengths of Ti 2 AlC and Ti 2 AlN originate from low slip resistance of Al atomic planes along the basal plane, and furthermore suggest that this is the mechanism for low hardness, damage tolerance, and intrinsic toughness of ternary layered carbides and nitrides.

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“…Like metals, they are electrically and thermally conductive, not susceptible to thermal shock, plastic at high temperature and exceptionally damage tolerant, and most readily machinable. Like ceramics, they are elastically rigid, lightweight, creep and fatigue resistant and maintain their strengths to high temperatures [2][3][4][5][6][7][8][9][10][11][12]. This makes them attractive for many applications such as structural materials at elevated temperature.…”

Section: Introductionmentioning

confidence: 99%

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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Processing and characterization of Ti2AlC, Ti2AlN, and Ti2AlC0.5N0.5

Cited by 519 publications

References 25 publications

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

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

Deformation modes and ideal strengths of ternary layeredTi2AlCandTi2
Liao
¹
,
Wang
²
,
Zhou
³

2006
Phys. Rev. B

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

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Processing and characterization of Ti2AlC, Ti2AlN, and Ti2AlC0.5N0.5

Cited by 519 publications

References 25 publications

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

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

Deformation modes and ideal strengths of ternary layeredTi2AlCandTi2Liao1, Wang2, Zhou3 2006Phys. Rev. B

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

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Deformation modes and ideal strengths of ternary layeredTi2AlCandTi2
Liao
¹
,
Wang
²
,
Zhou
³

2006
Phys. Rev. B