Microstructural design of hard coatings

Mayrhofer, P.H.; Mitterer, Christian; Hultman, Lars; Clemens, Helmut

doi:10.1016/j.pmatsci.2006.02.002

Cited by 869 publications

(423 citation statements)

References 276 publications

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“…Transition-metal (TM) nitride refractory ceramics possess outstanding physical and mechanical properties, including extreme hardness [1][2][3], high toughness [4][5][6], thermal stability [7,8], chemical inertness [9,10], and good electrical conductivity [2,11], which renders them important for a large variety of applications ranging from wear-resistant protective coatings on tools employed in industrial machining [12,13] to diffusion barrier in electronic devices [14,15].…”

Section: Introductionmentioning

confidence: 99%

Nonequilibrium ab initio molecular dynamics determination of Ti monovacancy migration rates in B1 TiN

et al. 2017

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We use the color diffusion (CD) algorithm in nonequilibrium (accelerated) ab initio molecular dynamics simulations to determine Ti monovacancy jump frequencies in NaCl-structure titanium nitride (TiN), at temperatures ranging from 2200 to 3000 K. Our results show that the CD method extended beyond the linear-fitting rate-versus-force regime [Sangiovanni et al., Phys. Rev. B 93, 094305 (2016)] can efficiently determine metal vacancy migration rates in TiN, despite the low mobilities of lattice defects in this type of ceramic compound. We propose a computational method based on gamma-distribution statistics, which provides unambiguous definition of nonequilibrium and equilibrium (extrapolated) vacancy jump rates with corresponding statistical uncertainties. The acceleration-factor achieved in our implementation of nonequilibrium molecular dynamics increases dramatically for decreasing temperatures from 500 for T close to the melting point T m , up to 33 000 for T ≈ 0.7 T m .

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Section: Introductionmentioning

confidence: 99%

Nonequilibrium ab initio molecular dynamics determination of Ti monovacancy migration rates in B1 TiN

et al. 2017

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“…It is well established that a thermal treatment, either postgrowth or upon the tool operation, strongly affects the coating film performance. For instance, one observes a formation of self-organized nanostructures [1][2][3][4] and modification of the films phase composition and microstructure at elevated temperature. The exposure of the transition-metal nitrides to high temperature and high pressure in technological applications can be either beneficial or detrimental, 5,6 underlying the importance of studies of their thermal stability, microstructure evolution, and hardness at conditions corresponding to operation conditions of cutting tools.…”

Section: Introductionmentioning

confidence: 99%

Temperature dependence of TiN elastic constants fromab initiomolecular dynamics simulations

et al. 2013

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Elastic properties of cubic TiN are studied theoretically in a wide temperature interval. First-principles simulations are based on ab initio molecular dynamics (AIMD). Computational efficiency of the method is greatly enhanced by a careful preparation of the initial state of the simulation cell that minimizes or completely removes a need for equilibration and therefore allows for parallel AIMD calculations. Elastic constants C 11 , C 12 , and C 44 are calculated. A strong dependence on the temperature is predicted, with C 11 decreasing by more than 29% at 1800 K as compared to its value obtained at T = 0 K. Furthermore, we analyze the effect of temperature on the elastic properties of polycrystalline TiN in terms of the bulk and shear moduli, the Young's modulus and Poisson ratio. We construct sound velocity anisotropy maps, investigate the temperature dependence of elastic anisotropy of TiN, and observe that the material becomes substantially more isotropic at high temperatures. Our results unambiguously demonstrate the importance of taking into account finite temperature effects in theoretical calculations of elastic properties of materials intended for high-temperature applications.

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“…Among these, TiN ranks as one of the most widely explored system due to its excellent performance as hard, wear-and corrosion-resistant coating. 1 An equally impressive scientific effort has been committed to TiN-based ternaries, primarily TiAlN, as the additional transition metals offer increased possibilities for fine-tuning mechanical and/or electrical properties by adjusting metal ratios. 2,3 For the same reasons, in recent years, quaternary compounds have received increasing attention in order to surpass the properties of TiAlN.…”

Section: Introductionmentioning

confidence: 99%

Electronic mechanism for toughness enhancement inTixM1−xN(M=M

2010

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Toughness, besides hardness, is one of the most important properties of wear-resistant coatings. We use ab initio density-functional theory calculations to investigate the mechanical properties of ternary metal nitrides Ti x M 1−x N, with M = Mo and W, for x = 0.5. Results show that Mo and W alloying significantly enhances the toughness of TiN. The electronic mechanism responsible for this improvement, as revealed by electronic structure calculations, stems from the changes in charge density induced by the additional transition-metal atom. This leads to the formation of a layered electronic arrangement, characterized by strong, respectively, weak, directional bonding, which enables a selective response to strain, respectively, shear, deformations of the structures and yields up to 60% decrease in C 44 values.

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Microstructural design of hard coatings

Cited by 869 publications

References 276 publications

Nonequilibrium ab initio molecular dynamics determination of Ti monovacancy migration rates in B1 TiN

Nonequilibrium ab initio molecular dynamics determination of Ti monovacancy migration rates in B1 TiN

Temperature dependence of TiN elastic constants fromab initiomolecular dynamics simulations

Electronic mechanism for toughness enhancement inTixM1−xN(M=M

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