Biomimetic hard and tough nanoceramic Ti–Al–N film with self-assembled six-level hierarchy

Meindlhumer, Michael; Zálešák, Jakub; Pitonak, Reinhard; Todt, Juraj; Sartory, Bernhard; Burghammer, Manfred; Stark, Andreas; Schell, Norbert; Daniel, Rostislav; Keckes, J.; Lessiak, Mario; Köpf, Arno; Weißenbacher, Ronald

doi:10.1039/c8nr10339a

Cited by 27 publications

(12 citation statements)

References 61 publications

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“…Existing literature based on this approach includes the incorporation of ductile phases into the ceramic matrix to hinder crack propagation [46,[68][69][70][71], ductile phases at nanocolumn boundaries [72], multilayer and nanocomposite structures to control crack propagation by deflection [63,[73][74][75][76][77][78][79][80][81], phase transformations [82][83][84][85], and carbon-nanotubes [86][87][88]. Other toughening methods include the introduction of compressive stresses to inhibit crack growth [63,[89][90][91], hierarchical nano/microstructures [92], crack deflection toughening using tilted interfaces [93], and grainboundary sliding [52,94,95]. However, most of these approaches [64,65] were developed for bulk materials and are not optimal for use in coatings, often leading to film delamination or a reduction in hardness [96].…”

Section: Introductionmentioning

confidence: 99%

A review of the intrinsic ductility and toughness of hard transition-metal nitride alloy thin films

et al. 2019

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Over the past decades, enormous effort has been dedicated to enhancing the hardness of refractory ceramic materials. Typically, however, an increase in hardness is accompanied by an increase in brittleness, which can result in intergranular decohesion when materials are exposed to high stresses. In order to avoid brittle failure, in addition to providing high strength, films should also be ductile, i.e., tough. However, fundamental progress in obtaining hard-yet-ductile ceramics has been slow since most toughening approaches are based on empirical trial-and-error methods focusing on increasing the strength and ductility extrinsically, with a limited focus on understanding thin-film toughness as an inherent physical property of the material. Thus, electronic structure investigations focusing on the origins of ductility vs. brittleness are essential in understanding the physics behind obtaining both high strength and high plastic strain in ceramics films. Here, we review recent progress in experimental validation of density functional theory predictions on toughness enhancement in hard ceramic films, by increasing the valence electron concentration, using examples from the V1-xWxN and V1-xMoxN alloy systems.

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Section: Introductionmentioning

confidence: 99%

A review of the intrinsic ductility and toughness of hard transition-metal nitride alloy thin films

et al. 2019

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“…Natural materials are evolutionary optimized materials that frequently feature hierarchical structures. They play an important role in bionanotechnology and composite materials [ 1 , 2 , 3 , 4 , 5 , 6 , 7 ]. Diatom biosilica is one of these biological materials, mainly from two sources: diatomaceous earth and living diatoms.…”

Section: Introductionmentioning

confidence: 99%

Morphology and Mechanical Properties of Fossil Diatom Frustules from Genera of Ellerbeckia and Melosira

Gluch

Liao

et al. 2021

Nanomaterials

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Fossil frustules of Ellerbeckia and Melosira were studied using laboratory-based nano X-ray tomography (nano-XCT), transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDS). Three-dimensional (3D) morphology characterization using nondestructive nano-XCT reveals the continuous connection of fultoportulae, tube processes and protrusions. The study confirms that Ellerbeckia is different from Melosira. Both genera reveal heavily silicified frustules with valve faces linking together and forming cylindrical chains. For this cylindrical architecture of both genera, valve face thickness, mantle wall thickness and copulae thickness change with the cylindrical diameter. Furthermore, EDS reveals that these fossil frustules contain Si and O only, with no other elements in the percentage concentration range. Nanopores with a diameter of approximately 15 nm were detected inside the biosilica of both genera using TEM. In situ micromechanical experiments with uniaxial loading were carried out within the nano-XCT on these fossil frustules to determine the maximal loading force under compression and to describe the fracture behavior. The fracture force of both genera is correlated to the dimension of the fossil frustules. The results from in situ mechanical tests show that the crack initiation starts either at very thin features or at linking structures of the frustules.

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“…The motivation of this work is to further extend the possibilities of in-situ XRD characterization, which will be used to obtain a complex picture of the multistage decomposition routes and also microstructure/strain changes in AlCrN-based thin films during thermal cycling. We use a newly developed in-situ high-temperature high-energy grazing incidence transmission synchrotron X-ray diffraction (HT-HE-GIT-XRD) 22 to simultaneously characterize temperature evolution of (i) phases, (ii) residual stresses, (iii) thermal strains, (iv) CTEs, (v) domain sizes and (vi) texture up to 1100 °C. Primarily, the onset temperature of the decomposition of metastable c-AlCrN into stable c-Cr(Al)N and w-Al(Cr)N phases has been investigated as a function of the as-deposited residual stress state and microstructure, intentionally predefined by the applied deposition conditions.…”

Section: Introductionmentioning

confidence: 99%

Stress-controlled decomposition routes in cubic AlCrN films assessed by in-situ high-temperature high-energy grazing incidence transmission X-ray diffraction

Meindlhumer

Klima

Jäger

et al. 2019

Sci Rep

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The dependence of decomposition routes on intrinsic microstructure and stress in nanocrystalline transition metal nitrides is not yet fully understood. In this contribution, three Al0.7Cr0.3N thin films with residual stress magnitudes of −3510, −4660 and −5930 MPa in the as-deposited state were in-situ characterized in the range of 25–1100 °C using in-situ synchrotron high-temperature high-energy grazing-incidence-transmission X-ray diffraction and temperature evolutions of phases, coefficients of thermal expansion, structural defects, texture as well as residual, thermal and intrinsic stresses were evaluated. The multi-parameter experimental data indicate a complex intrinsic stress and phase changes governed by a microstructure recovery and phase transformations taking place above the deposition temperature. Though the decomposition temperatures of metastable cubic Al0.7Cr0.3N phase in the range of 698–914 °C are inversely proportional to the magnitudes of deposition temperatures, the decomposition process itself starts at the same stress level of ~−4300 MPa in all three films. This phenomenon indicates that the particular compressive stress level functions as an energy threshold at which the diffusion driven formation of hexagonal Al(Cr)N phase is initiated, provided sufficient temperature is applied. In summary, the unique synchrotron experimental setup indicated that residual stresses play a decisive role in the decomposition routes of nanocrystalline transition metal nitrides.

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Biomimetic hard and tough nanoceramic Ti–Al–N film with self-assembled six-level hierarchy

Abstract: We demonstrate a biomimetic synthesis strategy, based on self-assembly from two variants of gaseous precursors.

Cited by 27 publications

References 61 publications

A review of the intrinsic ductility and toughness of hard transition-metal nitride alloy thin films

A review of the intrinsic ductility and toughness of hard transition-metal nitride alloy thin films

Morphology and Mechanical Properties of Fossil Diatom Frustules from Genera of Ellerbeckia and Melosira

Stress-controlled decomposition routes in cubic AlCrN films assessed by in-situ high-temperature high-energy grazing incidence transmission X-ray diffraction

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